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Green Street

A virtual street map to zero-carbon urban energy.

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Experience the greening of Green Street

The lowest cost heat decarbonisation pathway is in your hands.

The greening of Green Street augmented reality experience conceptualises and brings to life Kensa’s vision for the decarbonisation of heat in a real-life urban community in Glasgow, called Green Street!

Discover how an integrated approach using networked ground source heat pumps can deliver community-wide sustainable heating and cooling. A ‘green print’ for every street in the UK to accelerate progress on climate change through the lowest carbon, cost and electrical grid impact solution.

Securing a comfortable future

The electrification of heat will allow consumers to enjoy the same comfort levels and warmth as traditional heating systems, whilst being kind to the planet, and their pocket.

Achieving net zero at the lowest cost

By installing and funding the deployment of networked heat pumps via an infrastructure that mimics the gas network, net-zero carbon can be achieved for the lowest societal cost and significantly less investment than you think.

Connecting real communities to COP26

Modelled on the real Green Street just 2.5 miles from the COP26 host venue, Kensa’s Green Street experience provides a demonstrable local solution to deliver Scotland’s heat decarbonisation ambitions in line with COP26 goals, and a ‘street map’ for others to follow; any street, can be a Green Street.

Why is Green Street significant?

“To achieve our carbon reduction commitments, all of us, across society and the economy, must be connected to this united goal. Green Street connects the community, the commitment and the COP26 conversation.”

With heat pumps high on the agenda (600,000 a year by 2028 as per the 10 point plan for the UKs green industrial revolution), and the need to decarbonise heat being one of the most pressing and troublesome concerns to achieve our carbon objectives, the solution unveiled in Green Street is a concensed projection of how any street, anywhere, can achieve net zero at the lowest cost.

To meet the UK’s NDC requires a full switchover to low carbon heating.

The way we heat our homes has to change to secure our future.

By 2025, new homes will need to be built differently.

The energy efficiency of homes needs to improve to reduce fuel poverty.

Energy infrastructure and grid capacity must be enhanced.

A network of skilled heat pump installers will be needed.

How the UK transitions to net zero in homes and buildings is one of the biggest challenges on the climate agenda.

It is certain that heat pumps have an important role to play in the solution to this problem. The Sixth Carbon Budget by the Climate Change Committee states that the “Balanced Pathway” to meet the Sixth Carbon Budget will require over 1m heat pump installs per year from 2030, growing to 1.5m per year by 2050. It reads:

“The actions required to meet the budget and NDC (Nationally Determined Contribution), including full decarbonisation of the power sector, full switchover to electric vehicle sales and installation of low-carbon heating, and roll-out of carbon capture and storage, would go beyond those required from the world on average, in line with the UK’s responsibility as a richer nation with larger historical emissions. The timing of these actions would align to that required from other climate leaders.” 

Green Street is a model for how to achieve a full switchover to low-carbon heating, overcoming current barriers to the widescale adoption of heat pumps.

As we continually find – and as responses to Government policy over the last two decades have demonstrated – it is one thing to make low-carbon heating technologies available (heat pumps have been available since the 1800s), but it is entirely a different matter to achieve their installation in homes and their adoption for use on a mass scale. 

Green Street will show you how

Our world as we know it is changing rapidly. We have to embrace change to save the planet

The last few decades have seen major technological changes that are now intrinsic and commonplace to every day life. Consider the launch of the first modern smart phone, digital streaming platforms transforming how we view media (remember Blockbuster anyone?), and Uber revolutionising taxi’s. In the next decade, every car will switch to being an electric vehicle.

In contrast, the way we heat our homes has roughly been as it is today for about half a century – with the majority having natural gas piped into them for use with a condensing gas boiler.

Over the next few years, heat pumps will completely change how we heat our homes; but unlike the aforementioned advancements, this is not new technology (Kensa has been manufacturing ground source heat pumps since 1999, and the tech has been around since the 1800s). In this technological revolution, we are simply replacing one heating network (the gas grid and boilers) with another (ambient loops and networked heat pumps).

The impact of this change will be radical; heat is the single biggest factor in UK domestic energy consumption, contributing one-third of greenhouse gas emissions – ground source heat pumps emit no point of use emissions nor air pollution. As more renewable power feeds into the electricity grid, the same heat pump in your home will become even greener.

Now, new boilers are set to be banned by 2035, and the UK Government has committed to installing 600,000 heat pumps every year by 2028.

Switching to low carbon heating

In order for the UK to deal with the threat of climate change, the way we heat our homes has to change.

Based on a real-life urban community in Glasgow, ‘Green Street’ explores what the switch to low carbon, ground source heat pumps will be like.

What appliance will you have in your home and how will it be installed? How will the heat pump keep your home warm and comfortable, and affordable? How will this interact with other new technology in your life, such as an electric vehicle? How will low carbon heating secure a safer future for you and your family?

Green Street will show you how

If every home built is low carbon, there will be determined progress across the whole system.

The 2019 report by the Committee on Climate Change (CCC) ‘UK Housing: Fit for the future’ states that there are 29m homes in the UK and that the Government is committed to building an additional 1.5m by 2022. Thus, approximately 1.5% of all homes are new homes each year. By ensuring that all new homes are low carbon, we can address emissions in over 25% of UK homes over the next three decades.

Builders and developers of new homes are motivated to build high quality homes and sell them efficiently. New homes cost an enormous amount of money, which cannot sit tied up in unsold or part-built homes. There is, therefore, tension between building high quality, affordable homes quickly, versus changing the way homes are built and using technologies that builders and developers are unfamiliar with.

Connecting homes from the outset = less cost

Green Street demonstrates how new homes can be built with a similar cost model to previous methods; effectively, efficiently and low carbon.

‘Low carbon’ in homes is governed by ‘Part L’ and ‘Part F’ of the building regulations*. ‘The Future Homes Standard’ will come into effect in 2025, and in its 2021 consultation response, the Government confirmed that all new homes will be required to be equipped with low-carbon heating and be zero carbon ready by 2025.

If you are a builder – it is clear that within the next few years you are going to be building homes in a different way –

Green Street will show you how

More than 80% of homes will still be in use in 2050.

Most homes are not energy efficient (71% homes EPC E, F, G), and this leads to fuel poverty and accentuates social deprivation.

The need to decarbonise is not directly connected to the need to resolve social deprivation, and the causes of fuel poverty are not the same as the causes of global warming. However, there is strong overlap and the potential for ‘joined-up thinking’ in bringing solutions.

Eliminating the carbon emissions from an existing building will leave it more comfortable and more cost-effective to run.

Housing providers and Local Authorities are driven to provide quality and affordable to run housing. The social rented sector consists of 4 million households in England (18% of all households).

Financing the transition

The vision of Green Street is to separate the cost of the heat pump unit from that of the ground array, with external funders owning and operating a nationwide heat pump infrastructure.

As the housing provider upgrades properties in normal lifecycle management, it is simple to switch the heating appliance to an efficient, low carbon networked ground source heat pump for a similar cost to upgrading a boiler.

A lot of housing stock will require upgrading regardless of which type of low carbon heating is adopted. Networked heat pumps offer a whole life lowest cost option.

Green Street will show you how

Energy companies have two main obligations: to serve shareholders and customers.

Both of these core objectives are challenged by the transition to net-zero.

Energy companies need to determine how they will continue to generate consistent returns to shareholders, when some of the fundamentals of their business and the legislation around it, is being completely overhauled.

‘Keeping the lights on’ is more complex than most people begin to appreciate. The National Grid Infrastructure and the Electricity System Operator oversee and balance supply and demand with a complex array of engineering systems on the grandest of scales to ensure that the consumer is protected and that adequate power supply is maintained.

The electrification of transport and heat present changes to these systems unlike any that have been experienced over the last half-century.

Grid-friendly heat pumps and phased infrastructure upgrades

Understanding how much power will be required each year between now and 2050, and scaling up to meet the required capacity and ensuring that there is sufficient grid infrastructure is a huge challenge. Clearly, adding hundreds of thousands of electrically powered heat pumps to the grid – even with load-shifting initiatives – will require additional capacity, as will the widespread roll-out of electric vehicles.

Green Street sets out a blueprint for switching to low carbon heating street-by-street. This provides a manageable long-term plan for a phased increase of grid capacity, based on specific localities with favourable geology or immediate social drivers such as fuel poverty.

Separating the cost of the heat pump unit from that of the ground array, with external funders, such as energy or water companies, owning and operating a nationwide heat pump infrastructure in return for income via a long-term modest connection fee, is an attractive prospect and an excellent opportunity to establish a relationship with the householder.

Green Street will show you how

Plumbers qualifying today are learning skills that will be obsolete within a decade.

To pass an apprenticeship as a heating and plumbing technician, apprentices are required to demonstrate experience in the installation of gas boilers. In order to work in people’s homes, plumbers must be Gas Safe registered.

The Government has made it clear that fossil fuel boilers will not be installed in new homes from 2025, and that no new gas boilers will be installed from 2035 onwards.

The government has also made it clear that the future of home heating is low carbon energy-efficient heat pumps, a technology that at this present time, plumbers and heating engineers do not need to formally understand in order to be qualified in their role.

Bridging the skills gap

The certification and governance around the installation of heat pump technology (Microgeneration Certification Scheme) is relatively new and is working hard across the sector to support and encourage the uptake of good governance and quality standards with installers.

Unlocking the widespread adoption of heat pumps at a scale required to deliver the government’s target of 600,000 installations a year – and eventually enabling every street to transition to a ‘Green Street’ – requires the wholescale upskilling of plumbers and heating engineers to the different nuances of renewable heating devices.

Kensa’s products and installation methodologies have been designed with this transition in mind and we have worked to make the installation and the human interfaces as similar to boilers as possible and provide bespoke training opportunities.

There is a commercial opportunity here for savvy installers – everyone has a role to play in the transition to a low carbon future.  Now is the time to start upskilling in renewable heating technology.

Green Street will show you how

Behind the scenes at Green Street

Dig deeper into Green Street’s visionary journey and uncover how the ground beneath our feet can transform how we heat and power our homes and businesses, and provide a ‘ready-to-go’ solution for reducing emissions and tackling the climate crisis.

The 21st century 'gas grid': Networked heat pumps
Your journey through Green Street begins, ends, and starts over again, with our ambient heat network.
How a networked ground source heat pump works
Networked ground source heat pumps are proven to be the most energy-efficient heating technology available, resulting cheaper energy bills and a smaller carbon footprint.
ambient heat network infrastructure
Shared ground loop arrays with ambient loops are unobtrusive, scalable and should be regarded as the 21st century equivalent to the gas network
Load-shifting = grid-balancing
Heat can account for over 50% of a property’s energy consumption and this means that significant cost and carbon savings can be made by running heat pumps at off-peak times.
less power stations
The methods used to decarbonise and electrify heat will have profound implications for supply and demand, and will influence factors such as how many power stations we need.
Heating, cooling & waste heat
Shared Ground Loop Arrays with ambient loops act as a heating and cooling thermal energy supply grid all year round.
getting even greener
As the grid decarbonises, the carbon savings of electricity and therefore ground source heat pumps, become even greater.
The 21st century 'gas grid': Networked heat pumps

Where it all begins

The greening of Green Street is achieved primarily through the installation of an ambient temperature loop circulating low-grade heat energy to every building, ready to feed naturally occurring heat energy to a ground source heat pump to provide low cost and low carbon heating, cooling, and hot water.

Pre-installation of the ambient loop infrastructure means whole communities at Green Street, such as tower blocks, can switch to individual networked heat pumps simultaneously, as well as enabling individual households to easily and affordably make the transition from their gas boiler to a heat pump when they’re ready to change, with minimal disruption.

Free energy

The ambient loop connects every ground source heat pump to a communal, free heating or cooling source; we call these networked heat pumps.

The ambient loop harnesses sources of heat or cooling through shared ground loop arrays. These are often a series of boreholes, drilled up to 300m deep and no wider than a dinner plate. Other sources of heat also include aquifers, mine water, and available waste heat (such as excess heat from data centres and supermarkets).

The boreholes feed the low-grade heat from their source to the ambient loop – we call this the ambient loop because the temperature in the distribution pipework fluctuates to that dependent on the heat source, from anywhere between -5°C to 20°C, ready for the heat pump to upgrade or downgrade for heating or cooling.

The new 'gas grid'

The configuration at Green Street is much like the current gas grid system, but instead of the separately owned and maintained gas pipework in the ground feeding energy to individual gas boilers, we have separately owned and maintained ambient loop pipework feeding energy to individual ground source heat pumps.

The big difference is the former distributes highly flammable, highly explosive hydrocarbon fuel throughout our society; worse: when we burn it, we poison our local air supply with NOX and SOX, as well as the addition of green house gasses to the ozone layer. The later, our ambient loop and networked heat pumps, distributes an inert, water based, liquid for natural and safe heat exchange between homes and properties and the ground – no carbon emissions, no air pollution, no energy supply volatility.

utility model

We are all used to services paid for by the community, and used in the home using individual appliances. We do this currently with gas, water, electricity, data, and even roads and waste disposal. At Green Street the networked heat pump system is no different to the gas grid model – we call this Split Ownership; the underground infrastructure is funded, owned and maintained by an energy company, water company, local authority or private investor, removing the cost from the residents of Green Street. The utility owner recoups their investment via a standing charge similar to the gas network standing charge.

Delivering at scale across neighbourhoods offers significant cost reductions, whilst the end user is able to shop around for the best ground source heat pump and energy tariff much like they would when replacing their gas boiler and energy supplier contract.

Most importantly, for the residents and business at Green Street, the ambient loop and networked heat pumps provide the lowest running costs and carbon emissions than any other heating choice.

what heat sources can be used?

Networked Ground Source Heat Pumps exchange heat with an “Ambient Loop” – a submerged closed loop of pipework containing a mild temperature fluid.  At around 5 to 25 degrees, there are no concerns of heat loss between the pipe and the ground.

The heat pumps can either heat the building – cooling the loop a little – or cool the building – warming the loop a little.  When the heat pump cools the Ambient Loop renewable sources maintain the temperature of the loop.

These renewable sources may be conventional Ground Arrays, or waste heat from a variety of sources may be used, such as cooling, data centres, supermarket refrigeration, even tube lines or cooling electricity transformers.



  • Boreholes –Deep holes are drilled to depths of 100m to 250m and loops of pipe inserted to collect the heat from the surrounding geology. This is particularly useful where large areas of exposed ground are not available. Boreholes are the most common ground array for Shared Ground Loop Arrays and despite their great depth, are only the size of a dinner plate in diameter.
  • Slinkies (Horizontal coiled collector pipes) – Burying slinkies in trenches (1 – 2m below ground) is a cost-effective and easy-to-install means of collecting heat without any specialist equipment. However, a large area of exposed land is required.

water source systems

The technology can also extract heat from water sources as well. Water source systems make for extremely efficient heat transfer, as water is an excellent conductor of heat.

  • Surface water, closed-loop – This is an ideal option for developments next to rivers or lakes, where pond mats can be positioned in the body of water to extract the heat.
  • Seawater, open-loop – Seawater is pumped from the sea and the heat is extracted via a land-based heat exchanger.
  • Aquifer or mine water – Heat energy can be absorbed from the groundwater within an underground aquifer or mine. This can produce super-efficient systems, as mine water temperatures are typically around 15°C to 18°C.
How a networked ground source heat pump works

the physics of ground source

Ground source heat pumps are electrically-powered devices that have no point-of-use emissions, are non-combustion devices and emit no pollutants, hence are key in achieving the UK’s net-zero ambitions and helping to reduce a household’s carbon footprint. But how do they work?

Heat naturally flows from warmer to cooler places. A ground source heat pump exploits this physics by circulating a cold fluid through array pipework buried in the ground or submerged in water. It absorbs low-grade heat energy from external heat sources, such as rock, soil, lakes and streams, or waste heat.

The ground source heat pump then compresses and condenses this energy, upgrading it to a higher temperature, and transfers it to the property’s heating and hot water system. Having surrendered the absorbed energy from the ground to the heat pump, the fluid continues its circuit back to the submerged pipework to commence the cycle all over again.

Sustainable & reliable heat sources

The readily available ambient heat energy used by a ground source heat pump is predominantly stored solar energy, which is naturally replenished through direct sunlight and indirectly through rainfall.  The temperature below the surface of the ground is unaffected by changes in the outside air temperature and remains constant 24/7 365 days a year. Stored solar energy is different from deep geothermal heat, which is absorbed from the earth’s core by digging much deeper into the ground.

Networked ground source heat pumps also make use of the abundance of waste heat sources available in the built environment.  Typically, waste heat has been – well, wasted – and dumped to air, warming the environment around us, and warming the planet.  An ambient heat network can utilise this wasted heat to improve heating and cooling efficiencies.

This means networked heat pumps provide sustainable heating, cooling and hot water all year round without any loss of efficiency, keeping homes comfortable no matter what the season.

Higher efficiency = lower running costs

Networked heat pumps deliver the best low-carbon heating, producing more than a 77% saving on emissions versus gas. They are a highly efficient eco-friendly alternative to fossil fuels, which produce harmful carbon emissions. The current carbon intensity for networked ground source heat pumps is 50-100 g/kWh – compare this to the best gas boilers at 220-250 g/kWh.

A networked ground source heat pump is powered through electricity, delivering 3 to 5kW of renewable energy for every 1kW of electrical power it consumes. This efficiency makes networked heat pumps the most energy-efficient heating technology available, resulting in reduced running costs, cheaper energy bills and a lower carbon footprint. While modern condensing boilers can be over 90% efficient, a networked heat pump can achieve efficiencies of 550%. Compared to oil or LPG, you can expect to save over 30-50% on fuel run costs.

Heat pump differences

Networked ground source heat pumps are housed within the home – air source heat pumps by their very nature are housed outside the home.

Networked ground source heat pumps are naturally much more energy efficient than air source heat pumps. Sourced from a maintained, elevated ambient temperature network held at 15 to 20 degrees C, COPs – and annual SPFs – are kept above 5; whereas air source heat pumps will have SPFs around 3 and lower than 2 at colder times.

Further, at cold and damp times – a lot of the UK winter! – air source heat pumps are subject to icing up, and therefore required to put sporadic additional stress on the energy supply, which adds an additional efficiency performance factor.

Comparison Key facts


  • Implementing the networked ground source heat pump (NHP) solution for Green Street requires 45% less energy (2,000kWh) than an equivalent air source heat pump (ASHP) solution (3,500kWh.
  • NHPs generate less than 10% of the carbon of gas boilers today (0.26 tonnes versus 2.6 tonnes), and by 2050, when the grid is decarbonised, there will be no emissions. There is also no flue, and no local emissions polluting the air in Green Street.
  • NHPs generate approximately half the carbon emissions of ASHPs (0.26 versus 0.47 tonnes).
  • NHPs cost a lot less to run than an ASHP. The whole life cost of NHPs over 40 years is 35% less than ASHPs (£35,000 versus £53,000), and this does not include the additional infrastructure requirements that the electricity grid will require to operate ASHPs.
  • With split ownership, a utility company installs the ambient heat network. The cost to install the NHP is then no more than an ASHP.

Networked heat pumps in your home

Networked heat pumps emit a lower, more constant heat than a boiler, which provides intense bursts of high-temperature heat. This low flow temperature lends itself to underfloor heating or modern, larger surface area radiators designed for lower flow temperatures.

A networked heat pump uses heat from outside of your property. However, the heat pump itself is installed safely inside the property – in the same way as a traditional boiler. No louder than a kitchen appliance such as a dishwasher, they are quiet enough to be run any time of day or night.

A networked heat pump is easy to install in an airing cupboard or kitchen cabinet by any heating and plumbing installer. They are simple to control and can integrate with standard existing home heating controls, as well as other renewable technologies like solar PV and solar thermal.


Another benefit is that networked heat pumps have no annual servicing requirements, need minimal maintenance, and remove the hassle of fuel deliveries.

Compared to traditional gas boilers, oil or LPG systems, networked heat pump systems aren’t vulnerable to fuel price increases or energy security threats. They also use a non-combustion fuel source, so there is no fire risk.

ambient heat network infrastructure

Shared ground loop arrays

Kensa estimate the benefit of installing in a street by street manner brings as much as a 28% saving through volume economies of scale.

Shared ground loop arrays are unobtrusive, scalable and perfectly suited to large domestic developments, encompassing streets of houses to tower blocks.

Multiple properties benefit from the same borehole infrastructure and ground array installation costs can be reduced significantly the more properties that are added to the network.

It is an investment that will last for decades, as shared borehole ground arrays have a lifetime of up to 100 years.

low-carbon, low-cost gas grid alternative

As such, Kensa believes that the ambient loop should be regarded as the 21st century equivalent to the gas network, creating a renewable heat infrastructure that effectively mimics the existing mains gas model and allows the householder to have a ‘white box’ ground source heat pump inside the property that mimics a boiler.

Householders are understandably wary of heat networks (traditional district heating), where being locked into lengthy contracts with energy suppliers offer them with no choice and deliver heat at extortionate prices. Ambient loops are different, householders have independent control over the heating appliance in their own home (the networked heat pump) and the flexibility to switch suppliers and contracts as they wish. This also means no split-billing or metering requirements for landlords to worry about in tenanted properties either.

Many suppliers are launching heat pump centric tariffs which focus operation when electricity is lower cost (and lower carbon) so the running costs are also competitive with gas.

Street-by-street installation

Government suggests ‘local authority zoning’ as the most efficient route to widespread heat pump deployment, involving the “identification of areas which can be readily connected to a low-carbon heat network.”

Kensa agrees that a phased approach is the most sensible way to roll-out networked ground source technology, beginning with the areas with the most suitable geology, surface features, or sources of waste heat, as these are most conducive to lower-cost installations.

With careful planning and zoning, this “managed retreat” approach from the gas grid would involve disconnecting gas in key areas such as those with the highest air quality problems or the best geological conditions.

You would achieve higher carbon savings, lower running costs and then be left with a single, low maintenance, long life appliance and the ground array infrastructure would be in place for a century or more leaving a highly beneficial long-term legacy.


Kensa proposes separating the cost of the ground source heat pump unit from that of the ambient loop infrastructure, with external funders, such as energy or water companies, owning and operating a nationwide heat pump infrastructure that mimics the existing gas network. This is called split-ownership.

In a retrofit scenario, a householder or landlord could pay a small annual connection fee, much like the current gas arrangement, for a low carbon ground source heat pump to replace a gas boiler. This is even simpler in a new-build scenario where a single decision-maker can ensure every household is connected from the outset, and also means less cost for the housebuilder.

We recognise that many householders will need subsidy support to make the switch to ground source heat pumps, but this coupled with the long-term benefits of low running costs, increased efficiency, reliability and durability of the units, plus the freedom to independently control their heating and switch energy supplier to take advantage of flexible tariffs, should provide suitable incentive.

If this infrastructure is already provided, then plumbing and heating engineers could install ground source heat pumps on a neighbourhood scale, without involvement with the ambient loop infrastructure, just as they have no involvement in the supply of the gas network.

Load-shifting = grid-balancing

Smart controls & dynamic tariffs

Unlike traditional heat networks, the networked heat pumps installed across a community like Green Street allows the householders to have complete control over their own heating and hot water. This means they are free to switch energy suppliers and move from a flat rate tariff to a dynamic tariff if they wish.

Dynamic electricity tariffs offer cheap energy when electricity demand is low and renewable energy from wind or solar is plentiful (so low carbon); the price increases when the demand for electricity peaks.

Smart controls (think advanced thermostats) can cleverly synchronise with these flexible tariffs to automatically switch a heat pump on when electricity is cheap and switch it off to avoid the peak times when it is the highest cost, accommodating daily fluctuations. This is called load-shifting.

Grid Balancing – or rather – the benefit of using intelligent and smart controls to enable demand side flexibility to grid, has been conservatively estimated to offer savings to the consumer in the order of magnitude of 35%.

Lowest grid impact, maximum comfort

The carbon intensity of electricity roughly correlates with the cost, as electricity is cheapest when wind and solar generation is high. This means that load shifting of heating immediately reduces its carbon intensity.

This doesn’t mean that householders have to compromise on their comfort, however. These controls are so smart that they can learn user preferences ensuring that occupants have homes that are cosy and warm, with plenty of hot water, but for the lowest cost possible.

Smart controls can tell the ground source heat pump to subtly raise the temperature of the home to above optimum when electricity is cheap, for example, allowing the heat pump to turn off when electricity is most expensive, giving time for the building temperature to slowly cool to the preferred comfort level for when the occupant arrives home.

Dynamic duos

Networked ground source heat pumps are perfectly placed to participate in load shifting initiatives, as the ground is a very stable temperature heat source regardless of time of year or weather conditions. This means the heat pump can be run at the same efficiency any time of day or even overnight, when the grid generally has the most excess capacity without loss of efficiency.

If properly synchronised with dynamic tariffs, smart control of millions of devices such as networked heat pumps and electric vehicles will have a positive stabilising effect on the grid, turning on when there is overgeneration and turning off when the grid is under strain. Combined with the low electricity consumption of networked heat pumps, this will save billions of pounds of capital investment in future generating capacity.

Networked heat pumps produce more heat than the electric that they consume – for every 1kW of electricity used, 3 – 5.5kW heat are generated, and therefore they impose a reduced load on the grid. When using networked heat pumps in particular, this strain is further reduced because they are typically 20-25% more efficient than air source heat pumps, due to the stable heat source.

Driving down carbon

As all vehicles become electric vehicles (EVs), with the ban on new diesel and petrol cars in 2030, it will be critical for the grid to employ flexibility to allow for the charging of the EV as well as the powering of the heating system, and all other household energy needs. The integrated nature of networked heat pumps are optimally suited to engage with and create flexibility in the system.

There are two systems to enable balanced EV charging and heat pump operation:

1. Flexible electricity consumption in individual dwellings:

Charging times of the EV is integrated with the operation timings for the heat pump. Your plugged-in EV car only charges when the smart controls/learning algorithms deem it should, and not when your heat pump is operating/when you need heat, but in time to ensure the car is charged when needed. Both the EV’s charging and heat pump’s operation are anti-correlated with when you use other electrical consuming devices in the home, further lessening the electricity load and costs.

2. Cloud-based balancing:

For new developments and properties without driveways or the ability to have their own private EV charge point, we recommend coinciding the infrastructure work for the EV and heat pump; install the EV infrastructure with the ambient loop, and upgrade the power supply with underground cables. The heat pump then works together with the communal EV charger in a cloud-based system.

less power stations

Stable ground temperatures

Adding hundreds of thousands of heat pumps to the electrical grid will clearly increase electrical demand. By electrifying the grid using networked ground source heat pumps, as opposed to air source heat pumps or hybrid heat pumps, the required overall investment in electrical generation and supply (power stations and network upgrades) will be significantly reduced.

This is because the energy source for the networked heat pumps – the ground and waste heat – is stable 24 hours a day, all year round. This is extremely useful as networked heat pumps can therefore be run at any time of day or night when they have the least impact on the electricity grid, without losing efficiency. This is called ‘load-shifting’, as explained in the previous scene.

With the proper synchronization and smart control of thousands of networked ground source heat pumps, as well as other devices like electric vehicles, the grid can function effectively without the need for overgeneration. Less power stations on the horizon!

Networked ground source vs air source

Any heat pump roll-out programme featuring large numbers of air source heat pumps will require far more backup generation and storage capacity than ground source. This is because the efficiency of air source heat pumps is hugely compromised in cold weather when the air temperature drops, which coincides with when heat demand is at its peak.

Hypothetically, if all homes across the UK were installed with air source heat pumps, on the coldest day of the year the air source units would require additional power grid capacity equivalent to 2,400 x 10MW wind turbines or 8 x 3GW nuclear power stations versus the same homes heated with networked ground source heat pumps.

Networked heat pumps avoid the need to build the equivalent of eight Hinkley Point nuclear power stations!


Heat pumps run four times more efficiently than gas and networked ground source solutions drastically reduce the overall amount of electricity required, with one study stating ground source heat pumps could save the UK around £1bn a year to 2050:

“Not all electric heating is equal: technologies like network ground source heat pumps and thermal batteries can provide greater efficiency and flexibility, and in scenarios with greater deployment of these technologies we expect energy system costs to be lower by around £1bn a year on average to 2050, which is roughly 2% of total system costs.”

Aurora Energy Research Decarbonisation of Heat report.

Heating, cooling & waste heat

Shared Ground Loops transfer heat

Networked ground source heat pumps on Ambient Heat Networks get even cheaper with scale – introduce waste heat and cooling capabilities into the equation, and the installation costs get even lower. The additional benefit of the Ambient Loop – specifically the benefit brought by the use of waste heat – brings a 50% uplift to the performance of the heat pumps.

Warmer summers, improved insulation and larger windows are increasing the need for cooling in modern buildings. If a cooling system expels heat taken from a building into the surrounding air, this can raise the local air temperature, actually exacerbating the need for more cooling. And, any systems that produce carbon emissions are ultimately unhelpful in the fight against climate change.

Networked heat pump technology can provide low cost and low carbon cooling, as well as heating, reducing overheating without contributing to air pollution or climate change.

Cooling & waste heat

The by-product of extracting heat from the ground during the winter months is a large area of pre-chilled ground which is conveniently piped to the heat pump in each property to provide low-cost passive cooling during the summer.

For properties that need even more cooling, it is simple to reverse the heat pump so that it actively cools the property and sends the waste heat into the ground, effectively re-charging it for more efficient heating the following winter.

The ambient loop also offers the flexibility to integrate waste heat to act as an energy booster.  Instead of being wasted to the atmosphere, the ambient loop can recycle this waste heat, improving the efficiency of the system and reducing the cost of the ground array. When ambient loops incorporate heat from waste heat sources, the load profile for the heating may not match that for the cooling requirement; the ground array, therefore, acts as a natural ‘heat store’ allowing for inter-seasonal heat storage.

Waste heat opportunities

There is an abundance of waste heat in society which ambient heat loops and networked heat pumps can harness.

City centre urban environments particularly provide plenty of waste heat sources, such as the cooling of data centres,  supermarkets with refrigeration, heat from underground transport tunnels, and commercial air conditioning; 10% of all electricity generated in the UK is used in air conditioning.

The movement of electrical power in the electricity grid also creates waste heat (approx. 1/3 of it’s energy), and using the ambient loop to cool it not only improves the efficiency of heating, it improves the efficiency of moving the electricity also. There are a number of schemes where distribution step down transformers are being cooled to the heat network, having an effect to improve the efficiency of the heat network, whilst reducing the losses in the electricity grid.

A networked heat pump solution offers the opportunity to improve the efficiency of cooling, whilst also bringing benefit to the heating system.

getting even greener

Grand green ambitions

Over the coming decades, electricity will become increasingly important to the energy market, as fossil fuels are phased out.

The government has ambitions to increase the number of annual heat pump installations from around 30,000 to 600,000 by 2028, which amounts to a 20-fold increase.

In fact, the Committee on Climate Change (CCC) recommended that nearly 1 million annual heat pump installations will be needed to match the Sixth Carbon Budget.

Networked ground source heat pumps give the lowest running costs, and coupled with grid decarbonisation, offer the most compelling low-carbon case and net-zero solution.

The greening of the grid

Within the Progress in reducing emissions – 2021 Report to Parliament, the CCC highlighted that the decarbonisation of the energy sector in the UK has scaled up rapidly, producing 29% of the country’s electricity in 2020. This is being aided by the continuing falls in the prices of clean energy technologies.

With increasing contributions of sustainable power from wind, solar, wave, marine, the country’s electricity grid is decarbonising rapidly.

And as the UK grid becomes increasingly decarbonised, the carbon savings of electricity, and therefore the networked ground source heat pumps in Green Street, become even greater.

The carbon footprint per kWh of heat delivered by ground source heat pumps has actually dropped by 50% in the last 8 years.

The Real Green Street

Kensa’s ground-breaking ‘green-print’ for an integrated urban energy system is modelled on real flats, houses and buildings in a real community in and around a real Green Street, in central Glasgow (G40).

With Kensa’s experience of designing, installing and operating networked heat pump solutions at scale, we have considered the practical implications of bringing this solution to a real community.


Exploring the locality


Understanding property types


Determining current needs & future impact


Presenting the options & outcomes


We looked at every property, building and dwelling in Green Street. We considered access for installation of utility pipework, and spaces for Ground Arrays – we found that there is plenty of space within the public recreation areas.


We then considered the surrounding area, the adjoining streets and any significant local features that might require a higher heat load, or provide a consistent source of waste heat from cooling, air conditioning or refrigeration. We found suitable local schools, sports centres, commercial and municipal buildings.


We then looked to the surrounding postcode areas and found that Green Street is adjacent to Glasgow Green and the River Clyde; a potentially excellent source of renewable heat.

We also found that the G40 postcode is close to the Climate Neutral Innovation District. The proposed Innovation District could link to a Green Street ambient heat network and extend the benefit, impact and economies of scale across the city.


We then went back to Green Street to develop a suitable scope for the study having understood the area and surrounding region’s needs and opportunities, helping to inform an accurate data set of buildings in line with the economics of the available heat solutions.


We collated EPC (Energy Performance Certificate) data for the buildings on Green Street and in the immediate surrounding streets, constituting 880 dwellings.

We broke the surrounding streets into similar clusters of architypes, and understood that within a diverse collection of properties there are sub-sets of similar dwelling types.

We assessed groupings, understanding that mid level, top floor and ground floor flats have different levels of heat loss, age and fabric styles, in order to give us confidence in the results of a general collective study that consists of real individual buildings.


The existing houses and flats on Green Street and immediate surrounding area amount to 880 dwellings.

They require approximately 10GWh per year of heat, hot water and electrical power.

A typical Green Street flat will spend £1,000 per year across the life of their current gas heating system.

The annual emissions from Green Street based on their current gas system are 4,000 tonnes of CO2 for heating, hot water, power & transport.

Over 40 years Green Street will emit around 75 kilotonnes of CO2 if it remains on gas systems.


In order to understand the true cost of a networked heating system we calculated the “whole life” cost of the current gas system.  We considered 40 years to be an appropriate amount of time to consider to include for the lifecycle of plant and equipment, maintenance requirements and long term returns on choices.

We identified the grid distribution assets on Green Street and had discussions with Scottish Power to enable us to understand how consideration of future load will be managed.

We looked to the Energy Systems Catapult study “Living Carbon Free”  to understand how the total energy demand for individuals living on Green Street is likely to evolve.

Over 40 years the 880 buildings require approximately 350GWh of energy for heating and hot water, and – if using the technology currently in situ at Green Street (gas boilers) – will emit around 73 kilotonnes of CO2.


We then considered the costs associated with owning a gas heating system for the life of the heating system.  This includes the cost of replacing the boiler when it next breaks down, and replacing it a few times during the 40 year “whole life”, including regular maintenance, servicing and fuel run cost.

We considered a nominal cost of carbon at £50 a tonne, although we found that this was only a small component of the whole life cost.

Our calculations showed that a typical Green Street flat spends approximately £1,000 per year on average across the life of the heating system.

Source: Download our Green Street analysis here.


Over a 40 year “whole life, whole cost” assessment, networked heat pumps were similar to gas, and over 1/3 lower cost than air source heat pumps.

Replacing the heating system with low carbon heating was more cost effective than expensive solid wall insulation.

Networked heat pumps require 45% less energy than an air source heat pump. 

Networked heat pumps offer a 90% carbon emissions reduction over gas - as the electricity grid is decarbonised fully, the emissions from networked heat pumps are fully eliminated.

With Government assistance for utility-scale deployment and an annual connection charge, networked heat pumps are an affordable solution.


We found that over a 40 year “whole life, whole cost” assessment, Networked Heat Pumps were similar to Gas and over 1/3 lower cost than stand alone Air Source Heat Pumps.

Our “whole cost” assessment included the costs of financing the installation.  Utilisng our split-ownership model, we separated the ground – infrastructure – side of the installation, the heating appliance installation and any internal heating distribution system upgrades required.

With regards to the heating appliance, we considered the substitution cost – i.e. the difference in cost – compared to replacing the existing gas boiler.

We used standard air source heat pump operating data, and we considered networked heat pumps operating from an ambient loop maintained at temperatures between 10 and 15 degrees, although in reality we would anticipate temperatures to be between 15 and 20 degrees.

We considered heating costs based on existing fabric heat losses.  We conducted a cost benefit analysis on upgrading fabric, and for the purpose of this study, identified that replacing the heating system with low carbon heating was more cost effective than expensive solid wall insulation.  Further, for the purpose of comparison, if solid wall insulation was deemed suitable, then it would be applied regardless of technology, and the costs would cancel out.


The use of networked heat pumps shows the lowest energy requirement, 45% lower than an air source heat pump.  Using SAP 10.1 carbon emissions, networked heat pumps offer a 90% reduction over gas, with the added benefit that as the electricity grid is decarbonised fully, the emissions from networked heat pumps are fully eliminated.

We allowed for savings through load shifting.  We included more savings for load shifting with networked heat pumps since they can run at the coldest of times with no loss of efficiency, and through the night with no concerns over noise.

We considered different business models for financing the ground side as a utility and found that this requires scale, and we recommend that this is the focus for Government assistance.  We found that with an annual connection charge to pay for the financing of the installation over the long term, networked heat pumps are an affordable solution.

This analysis does not include the significant additional cost required for grid upgrades to support the increased requirement of air source heat pumps.  We have also not taken into account lower performance or strain on grid capacity of air source heat pumps at the coldest of times.

Source: Download our Green Street analysis here.

Will your street be the next ‘green street’?


The quickest and most effective way to follow Green Street’s ‘green print’ for the mass transition to networked heat pumps, is to first focus on properties where a single entity can require all households to connect to an ambient loop network.

Quick wins could include:

  • Social housing retrofit
  • Residential new build


Private housing retrofit is also a key sector that will benefit substantially from the Green Street ‘green print’, however this requires multiple decision makers.

If you are part of a community initiative that is committed to zero carbon then get in touch, we’d love to help


If you are a developer, landlord, or tenant, and are keen to progress your street’s journey to decarbonisation, then get in touch with Kensa and we would be happy to discuss the next steps.

Fill out my online form.

Low carbon integrated energy systems explained

Delve deeper into the technology featured at Green Street, and explore additional integrated systems mutually benefitting from the networked heat pump solution, including electric vehicle charging, local battery storage and hydrogen fuel cells.

Introducing Kensa

Since 1999, Kensa has manufactured and supplied ground source heat pumps from the heart of Cornwall. To date over 1 million tonnes of carbon will be saved as a result of our ground source heat pump installations across social housing, new build developments, private retrofit homes, and businesses.

Kensa is driving the mass adoption of ground source heat pump technology through a street-by-street and split ownership approach, utilising readily available technology with innovative system designs. ‘Welcome to Green Street’ provides a green-print for how we meet the UK’s target for 600,000 heat pump installations a year by 2028, and deliver the necessary reductions in carbon emission and air pollution to achieve net-zero 2050.

Think big

We are calling on the UK government to think ‘big’ to cut carbon emissions by replacing the gas grid not just boilers.

The Kensa Group, the UK’s only manufacturer of ground-source heat pumps, is calling for government to think ‘big’ when using heat pumps rather than just funding boiler replacements on a house-by-house basis.

The only way to reach the volume of heat pump installations required by government (600,000 per year by 2028) is to create a large networked solution that mimics and replaces the current gas grid.

Simon Lomax, Kensa Group CEO:

“Whilst the Heat and Building Strategy confirms the key role for heat pumps in decarbonisation, the Boiler Upgrade Grant is underwhelming and lacks both ambition and scale.

It isn’t possible to reach critical mass or secure the cost reductions expected by Government by adopting an ad hoc house-by-house approach, placing the responsibility to deliver our climate targets on individual consumers. To reach the volume of installations required we envisage a street-by-street, split ownership approach.

To really kick-start the transition to heat pumps, the Government needs to work with the energy industry and suppliers to popularise a networked ground source heat pump solution at scale, mimicking and replacing the gas grid approach.  The cost of the underground infrastructure is divorced from the heat pump, again following the approach used in the gas sector.  This solution can be delivered immediately.  Indeed, Kensa has already completed large scale installations in all types of housing.  Emerging studies will highlight this approach as the lowest cost decarbonisation pathway.

In the Kensa Vision, the underground infrastructure is funded, owned and maintained by an energy company, water company, local authority or private investor, removing the cost from the consumer.  The utility owner recoups their investment via a standing charge similar to the gas network standing charge.  Delivering at scale across neighbourhoods offers significant cost reductions.   The infrastructure uses the natural heat in the ground and the source temperature can be further bolstered by the use of waste heat to improve efficiency.  Running costs and carbon emissions will be far lower than any other heating choice.  Pre-installation of the infrastructure means whole communities such as tower blocks can switch to individual networked heat pumps simultaneously, as well as enabling households to easily and affordably make the transition from their gas boiler to a heat pump when they’re ready to change, with minimal disruption.

This approach delivers the very best outcomes for the householder and the environment and puts less pressure on the electricity grid.  It will also maximise job creation in the UK.  We will continue to encourage the Government to recognise the need for more appealing low carbon heating choices to accelerate the transition to net zero.

Green Street is our way of setting out a virtual street map that proves any street can be a Green Street, by showing how the ground beneath our feet can transform how we heat and power our homes and combat climate change.”

The Kensa Group at COP26

Our goal was to put heat on the agenda at the UN Climate Change Conference, and we are therefore proud that Kensa’s Shoebox heat pump was the only heating appliance on display at the summit.

As well as launching the ground-breaking ‘Welcome to Green Street’ AR experience, Kensa was involved in a number of other initiatives at COP26 that have wider implications on the future of decarbonisation of heating.


Kensa had a presence in the Blue Zone on the 11th of November for the Cities, Regions and Built Environment Day and presented a showreel on the Kensa Vision including the Green Street AR experience.


Kensa’s small-but-mighty Shoebox, which has revolutionised renewable heating in flats and apartments, was on display in the Green Zone throughout the summit.

Energy and Climate Change Minister Lord Callanan took time out during the Cities, Regions and Built Environment Day at COP26 on Thursday to visit our stand. Along with many other visitors, he took part in the Welcome to Green Street augmented reality experience.


The Kensa Group was delighted to be one of the winners of the esteemed Ashden Awards at COP26, which honour pioneering organisations “lowering carbon emissions and building a fairer world”.

Kensa won the Climate Innovation category for a groundbreaking renewable heating upgrade project with Together Housing, which was presented by the President of Costa Rica, Carlos Alvarado.

Kensa has pledged to use the prize money to set up a Social Impact Fund tackling fuel poverty with an intention to help customers most in need.


Kensa’s Factory Supervisor, Marie Hand, was named as an Everyday Climate Hero in this national campaign.

Her portrait taken by world-renowned photographer, Rankin, was on display in an exhibition in the Blue Zone at COP26 and on over 400 billboards throughout the UK.

The campaign sought to bring to the forefront the unsung heroes working to fight climate change during the COP26 conference.

BEIS COP26 Domestic Campaign

Kensa’s tower block project with Croydon Council was featured on the online BEIS & Greater SE Energy Hub COP26 Domestic Campaign.

The project aimed to amplify the aims and impact of COP26 at a local level, showcasing what individuals and organisations have accomplished, and encouraging and stimulating others to take their own next steps.


In a message to world leaders, the #StopBurningStuff Manifesto sets out existing solutions to today’s environmental problems. Fully Charged, the world’s largest electric vehicle and clean energy channel released the clean energy and transportation manifesto, supported by some of the most pioneering businesses from across the energy and transport sectors, including Kensa Heat Pumps, challenging global governments to quit the chat and act today.

Kensa’s Round Table Events

On the run up to COP26 Kensa hosted a series of round tables addressing the urgent need to decarbonise the UK’s housing stock and the best solution to do this. A consensus paper following COP26 will conclude the findings from the top tier stakeholders involved in the discussions, including BEIS representatives.

Scottish Renewables Year of COP Partner

Kensa was involved in Scottish Renewables’ Year of COP campaign throughout 2021, including renewable energy roadshows taking the COP message to remote communities throughout Scotland.