Insulation and Heat Pumps: The Perfect Pairing

Insulation and Heat Pumps: The Perfect Pairing

The UK is in the process of gradually switching our heating systems to highly efficient, low carbon alternatives such as heat pumps. MIMA welcomes this vital transition which supports the country’s decarbonisation goals, driving a significant reduction in carbon emissions and energy use over the coming decades.

Good insulation, installed well, will continue to have an essential role to play in supporting efficient and affordable home heating, and especially where electrically powered heat pumps are concerned.

Loft, wall and floor insulation, better glazing, and measures to reduce draughts and cold spots in homes, all cut the amount of heat a household needs to stay warm, meaning fewer units of electricity consumed each day to power any heat pump. With electricity unit prices currently at around four times the price of gas[1], on average, every unit saved will make a big difference to energy bills.

Air source heat pumps also often run with low radiator flow temperatures, some as low as 35 degrees centigrade, or less. The lower the flow temperature, the better the efficiency of the heat pump[2], and the lower a household’s electricity use and fuel bill will be as a result. Insulation helps the home retain heat and supports comfort at these lower flow temperatures, also enabling people to use heat at times of the day when tariffs are cheapest.[3]

The government’s recent Electrification of Heat project[4] has helped to demonstrate the excellent and improving efficiency of heat pumps. As part of this project, the team made sure that the 740+ homes in the trial received the additional measures needed to support the performance of the heat pumps being installed, such as larger radiators. The insulation was also upgraded in some of the properties. Nearly every home had some form of additional work alongside the fitting of the heat pump, and project costs factored this work in.

Going forward, when fitting a heat pump, or any other new heating system, homeowners should be encouraged to install insulation where suitable for the property, and to discuss with heating engineers what other additional measures are needed to get the best out of their new system.

If insulation is not then fitted as part of a heating system upgrade project, the implications for annual space heating demand, system sizing (and cost), comfort, and long-term running costs should be made clear to the client. Fitting insulation as part of the wider heat pump installation project is likely to be the most cost-effective route compared to doing the work further down the line, and the bill savings realised over time will often pay back the upfront insulation costs.

We would also encourage heating engineers out on projects, preparing heat loss calculations, to point their clients in the direction of government funding schemes to help with the cost of installing insulation, including the Great British Insulation Scheme[5], as well as funding for heat pumps.

[1] See Get energy price cap standing charges and unit rates by region | Ofgem
[2] See In-depth guide to heat pumps - Energy Saving Trust
[3] See (30) Running my heat pump for half the cost of a gas boiler… | LinkedIn
[4] See BEIS Electrification of Heat (
[5] See Apply for support from the Great British Insulation Scheme - GOV.UK (