Why Heat Pumps Are Not Yet Ready To Replace Gas Boilers

If you are planning to fit a new boiler in your London home because the old one needs replacing, you may have been tempted to consider a different option for warming your home and water supply, such as an air source heat pump.

However, there may be very good reasons not to do this – and they come from someone who owns his own heat pump company.

Business tycoon Lord Willie Haughey has attacked the Scottish government’s plans to try to force homes to switch to heat pumps by penalising those with boilers. Under the proposals, from 2025 any home with a gas boiler won’t be able to achieve an energy performance rating of C and will be legally barred from being sold.

Lord Haughey said that while he should be “jumping for joy” because he owns a heat pump company, he warned that the devices “don’t work as efficiently in Scotland as they do in other countries”. A key problem is that they stop working properly if the temperature drops below -5C, which is common in many parts of Scotland in winter.

That issue may be less of a concern in London, where it is rarely so cold, but another issue the peer pointed out is that the pumps can only heat water to 54 degrees C, less than the 60 degrees needed to kill off legionella bacteria.

Another problem, identified by the Scottish government’s own research, is that heat pumps are not suited to tenement blocks, which make up 40 per cent of Scottish housing stock. Such buildings of large-scale multiple occupancy are similar to the kind of properties a large proportion of Londoners live in, so the same would be likely to apply here.

The Scottish proposals will be subject to public consultation. But if that exercise highlights major weaknesses in the use of heat pumps, the consequences for government policy could not only be to delay their wider deployment in Scotland, but slow down their introduction – and therefore maintain the reliance on gas or electric boilers – down here in England too.