Ground Source Heat Pumps for Housing Developments

Why are heat pumps ideal for developments?

They deliver safe heating

Every Kensa ground source heat pump use a non-flammable refrigerant. This ensures safe heating for residents, providing a risk-free alternative to fossil fuel systems and renewables using flammable refrigerants.

They achieve carbon compliance

Ground source heat pumps with Shared Ground Loop Arrays offer developers a cheaper and easier way to achieve carbon reduction targets, to meet and exceed building regulations.

For developers working to achieve more than 30% carbon savings compared to building regulations, SAP 10.1’s proposed reduction of the carbon emissions for electricity to 0.136 kgCo2/kWh means ultra-efficient ground source heat pumps have emerged as a simpler, more effective and efficient heating system. Especially when compared to traditional district heating measures such as gas CHP (Combined Heat and Power).

Under SAP 10, the carbon saving for ground source heat pumps compared to gas CHP is up to 70.9%. This makes carbon compliance easier and cheaper in developments – avoiding the costly addition of energy-saving measures, which gas CHP systems would otherwise require.

They can save developers & purchasers money

Developers can attract an external investor to fund the heat pump underground pipe network – the costliest element of a ground source heat pump system. This model is known as split ownership.

Split ownership reduces the system cost for developers. The ground array owner may be inclined to replicate a gas infrastructure and charge connection fees to the network. Meanwhile, the property purchaser retains ownership of the ground source heat pump to enjoy low-cost and low-carbon independent heating and hot water.

They can be combined with smart controls

Ground source heat pumps are unique in their ability to participate in load shifting initiatives. Their stable source temperature makes them well suited to running when the grid can best support it.

When ground source heat pumps are enhanced with smart controls, heating schedules can be cleverly programmed to learn the occupant’s preferences and building heat physics, automatically taking advantage of dynamic tariffs to run the heat pump when prices, and the carbon intensity of electricity, is at its lowest. Kensa models show that savings of 25% – 40% are achievable.

The combination of energy storage local to the heat pump will further lower grid demand. For example, it is cheaper to run a heat pump overnight because this is an off-peak time for electricity consumption. Heat can be stored in the night and used the following day, reducing the cost of consumption from the grid at peak times and therefore saving on heating bills and carbon. Smart controls use these external factors to help would-be purchasers make informed decisions with their heating. A great selling point for developments.

Daily average cost & carbon of electricity*

*Daily average cost and carbon graph: Base electricity charges based on Sheffield averaged on the Big Six once a month – average electricity cost per kWh (www.ukpower.co.uk/home-energy/tariffs-per-unit-kwh, www.nottenergy.com/energy_cost_comparison). Octopus Agile Tariff (average over 24hrs). Average CO2/kWh over 24hrs in winter (www.carbonintensity.org.uk)

They could replace gas systems by 2025

The government has committed to the end of gas, and all fossil fuel heating, in new builds from 2025. This forms a part of government legislation to make the UK carbon-neutral by 2050 and follows the declaration of a global climate emergency. These vital targets, as well the government’s announcement of a target to slash UK carbon emissions by 78% by 2035, only strengthens the case for ground source heating.

It’s vital that developers anticipate a gas ban as part of future developments, as ground source heat pumps will be at the forefront of new-build heating options – rivalling and replacing the gas grid.

How do the carbon costs compare to gas?

Carbon costs of heat pumps vs. gas

This example is based on a 1,500-unit development featuring Kensa Shared Ground Loop Arrays and ground source heat pumps:

*Based on SAP 10 carbon figures and £95 per tonne of carbon.

How do heat pump costs improve as the scale of the project increases?

For large-scale ground source heat pump projects, the cost of an installed system per property is much lower than for a system in a comparable individual home.

Typically, costs could be reduced by approximately 30% to 50%. This is because some of the fixed costs of a single unit project, for example, moving the drilling equipment to and from site, are spread across a greater number of properties on housing developments.

Economies of scale

In Shared Ground Loop Array schemes where multiple properties share the same boreholes, much fewer boreholes can be drilled to much greater depths (120 – 200m). This increases the spacing between boreholes and reduces drilling and trenching costs. It also allows the system to cope more naturally with high heat users, by sharing that extra demand over the whole site.

In addition, economies of scale are achieved from drilling more boreholes and supplying more ground source heat pumps. With all else being equal, the higher the number of properties on a project, the lower the installed system cost per property.

Kensa Heat Pump’s sister company, Kensa Contracting, specialises in delivering large-scale heat pump projects.

Heat pump case studies for developments

40 new luxury apartments in Cornwall

Transforming the old grounds of a derelict hotel, Acorn Property Group built a luxury development just metres away from the sands of Perranporth beach. With the apartments being off-gas, it made sense to install ground source heat pumps. Heat pumps not only complemented the development’s natural surroundings, but paid off in terms of carbon reductions and comfort.

Speaking of the project, David Stein from Acorn commented:

Aside from the advantages associated with the adoption of renewable energy in respect of improved SAP rating, lower carbon footprint, and generally ‘feeling good’, ‘The Dunes’ was a natural candidate for ground source heat pumps. There is no natural gas in the area and the geology is known to be highly suited to GSHP’s. […] We realised we could eliminate any centralised plant, thereby increasing sales area and at the same time offer direct individual control and metering of their heat source to individual purchasers.