Substantial reductions in the UK’s CO2 production will not be achieved without improving the energy efficiency of the built environment. This means fixing existing buildings, not just building more efficient new ones.
Heat pumps are not a new technology, but in the UK, despite government programmes such as the Renewable Heat Incentive (RHI – to be discontinued in 2022), they have not gained widespread acceptance in the residential market. This is essential if they are to make any worthwhile contribution to reducing the built environment’s energy consumption.
The scale of the problem is huge. Part of the answer, the government has suggested, is to install 600,00 heat pumps every year by the end of the decade. This is wishful thinking.
Government figures (Non-Domestic and Domestic Renewable Heat Incentive (RHI), monthly deployment data [Great Britain]: April 2021)show that since 2014 only 55,000 air source and 12,000 ground source heat pumps have been installed under the RHI scheme (excluding those in new buildings, which are outside the scheme). Additionally, in England, only 0.77% of dwellings with an EPC (Energy Performance Certificate) use heat pumps as their main method of heating (Ministry of Housing, Communities and Local Government – Energy Performance Certificate data on Open Data Communities [financial year ending 2019]). In comparison, gas accounts for 79%.
Disincentives in the market act as barriers to faster uptake of the technology.
First, consider EPCs. The rating system favours solar panels (renewable energy) over heat pumps (efficient, but still electrically powered). Prior to a 2016 ground-up restoration, my 19th-century stone cottage had a ‘G’ EPC rating. The restoration included a new insulated floor slab, underfloor heating and internal insulation of the external walls. The rest was new build to current regulations. In addition, the all-electric property has loft insulation, double glazing, LED lighting and AAA-rated appliances. The resulting EPC rating was ‘D, just missing ‘C’ because of the lack of solar PV panels.
“Electricity is approximately 5x more expensive than gas and 3x more expensive than oil per kWh hour“
Next, consider energy prices. Electricity is approximately 5x more expensive than gas and 3x more expensive than oil per kWh hour. A switch to electricity requires impressive efficiency gains to offset these higher costs. As with car fuel economy figures, the efficiency of heat pumps in use depends on many factors, but it’s not unreasonable to assess air source pumps at 300% and ground source ones at 500% efficient. Air source pumps are less expensive and disruptive to install than ground source ones, so may often be the better option for retro-fitting installations.
These figures show that while ground source pumps can compete with gas on running costs, air source ones may only do as well as oil. The disruption and installation costs of replacing an existing heating system may be substantial. It is hard to imagine such a product achieving mass market penetration if it is then also not cheaper to run.
To date, much of the cost of subsidising the shift to renewable energy sources, such as wind farms, has been met by loading it on to electricity prices. This seems to be the reverse of what’s needed to encourage customers to switch to electricity.
“New houses will look obsolete within 10 years if current promises about no new gas connections come to fruition”
Inconsistent government policy in recent years has also not helped. Heat pumps are still not required by the building regulations. Thousands of new houses continue to be connected to the gas network. This could have been changed at least a decade ago. Those new houses will look obsolete within 10 years if current promises about no new gas connections come to fruition.
The RHI pays grants to customers who install an approved heat pump system (typically around £100 per month for seven years), supported by a certification scheme – MCS ( Microgeneration Certificate Scheme) for installers. Many customers have found the MCS standard is a bare minimum and does not guarantee the installer knows what they are doing. Many installers found the anticipated new work that would justify the training and certification costs did not materialise. They dropped out of the scheme and returned to their traditional business.
Today there remains a huge shortage of qualified and experienced designers and installers of heat pump systems. It is inadequate for the current level of installations, let alone 600,000 per year.
This is critical. Although the technology is established, heat pump systems are more complex to use than conventional boilers. They are also more sensitive to poor design and configuration of the installation. If a gas boiler is not working optimally the cost of the extra gas may hardly be noticeable, but the high price of electricity means that any excessive use soon becomes apparent.
The systems also require different consumer behaviour. Gas and oil-fired boilers can produce heat on demand. Heat pumps run best at a constant level. There is no turning the thermostat down when leaving your house and back up again on your return. Find the temperature that is comfortable for you and leave it there 24/7.
The control systems on heat pumps are more complex. Residential customers used to a thermostat in the hall and a timer in the airing cupboard will find them more challenging. You must engage with this to get optimal performance.
Most telling, perhaps, is that there are online forums for owners of heat pump systems. It is laughable to imagine anyone doing this to discuss their gas central heating. There is no need to – generally, they just work as expected. In a different context these forums might be called survivor groups. It is not that everyone has a disaster story, but there are many issues (not least resulting from poorly specified, designed or installed systems). The forums are generally frequented by well-informed articulate people with an enthusiasm for renewable energy who have had the money to spend on these systems. That is not the customer profile of a successful mass market product. We will know we have that when such forums no longer need to exist
