Do these reflect real-world scenarios?

One important difference between this piece of research and others is that the heat pumps are modelled to run most of the time, replacing a more intermittent heating regime for the baseline fossil fuel boilers. The modelling identifies this as the most cost-effective method of operation for the heat pumps, but it leaves them running overnight and in unoccupied periods. As a result, the modelled homes all see their overall amount of heat energy provided into the home increase which impacts on running cost savings versus the baseline. We think this is an important area for further investigation – how gas boilers are used at the moment and how heat demand changes as people move to heat pumps and whether there are other benefits from the more constant temperatures that these are expected to produce in the real world (e.g. improved comfort and liveability of the home).

This study used a sophisticated energy model (CAR’s ScotCODE, built using the EnergyPlus open access model) but the results are contingent on a wide range of assumptions about technology costs and performance and the heating requirements of the people living in the home. While the 12 archetypes allow us to reflect a lot of the diversity that exists within Scotland’s housing stock, there will still be variation in the costs of installing and running heat pumps in the real world.

These modelled results should therefore be considered as a way of exploring these topics further and should not be used for home decarbonisation decisions – for which Home Energy Scotland provides a comprehensive service To find out whether your home in Scotland might be suitable for a heat pump, you can ask Home Energy Scotland to carry out a home survey for you. You can also find useful information at Nesta’s information site GetAHeatPump.org.uk and arrange to see a heat pump in action and get your questions answered by heat pump owners at VisitAHeatPump.com.

Policy recommendations

1. The UK Government should reduce levies that are currently applied to electricity costs to reduce the ratio between electricity and gas prices so that it is more favourable towards electric heating.
2. The Scottish Government should move forward with its plans for a Heat in Buildings Bill. The sooner a Bill is passed, the longer households and industry will have to prepare for it. We think this should include a requirement for a heat pump (or other clean heating) to be fitted within two years of a house purchase. This modelling has shown that with the right policies in place, the vast majority of households should have lower costs as a result of fitting a heat pump. In addition to significantly lower climate change emissions, homes will no longer be exposed to volatile fossil fuel prices and should see increased property values.
3. Ongoing grants and low-cost loans for funding for homes will be crucial to introducing the Heat in Buildings Bill proposal soon. Full support should be provided to low-income households through fuel poverty alleviation schemes, with upfront grants provided to everyone else. A sliding scale should be considered.
4. Time-of-use tariffs are likely to be beneficial to many heat pump owners and policy should ensure that these are available to as many households as possible through enabling actions like the smart meter rollout and ongoing research into the end-user experience.

This was an update to previous modelling carried out for WWF Scotland in February 2023.
These should be read together, for full understanding of the methodology used.