Sus corresponsales son demasiado pesimistas acerca de las bombas de calor para casas y pisos (Letras, 20 octubre). Las bombas de calor pueden ser inusuales en Gran Bretaña, pero son una industria importante y muy extendida en Europa y en otros lugares. They are used in Canada, where outside temperatures drop very low. Individual units may not be suitable for high-rise blocks – although they might be installed on balconies. But high-rise buildings make up a small fraction of the housing stock, and blocks can have communal heating and cooling with large centralised heat pumps.
Older heat pumps were noisy, but new makes are on the market that are much quieter. It is not true, except in the worst cases, that installing heat pumps requires dwellings to be insulated first. The great majority of houses and flats in the UK are already reasonably insulated, and heat pumps can be run for longer and at lower temperatures than gas boilers. Better insulation of existing gas-heated houses and flats will by itself only produce modest cuts in carbon emissions. To meet climate goals, we have to stop using gas.
Y, por cierto, hydrogen as a domestic fuel – being pressed hard by the gas companies – is a distraction. It has to be made either from natural gas, which produces CO2 and can also release methane, a much more powerful greenhouse gas. Or it can be made with electricity, by the electrolysis of water. But why would one not in that case supply the electricity direct to houses, for resistance heating, or for powering heat pumps?
UCL Energy Institute
Your correspondents who express reservations about heat pumps show no sign of ever having operated one. We have, ya que 2016, and it’s been one of the best things we ever did. Por qué? 1) Savings on the previous solid fuel system are around £800 per year. 2) Any sound is inaudible from within the house. 3) The system has coped effortlessly with -10C, which is hardly surprising given that it’s a Swedish model geared up to much lower temperatures than that. 4) It has proved totally reliable and fault-free. What’s not to like?
In response to readers sceptical of the government’s plans to replace our polluting gas boilers with heat pumps, there are some myths that urgently need debunking. Heat pumps already work in freezing Scandinavian winters, and they can certainly work well in flats. No working boilers will be ripped out, but replaced when they break with something cleaner and better for energy bills.
The UN secretary general has sounded a “code red” for humanity, and heat pumps are the only viable solution for clean, energy-efficient heating that can address the 14% of UK climate emissions coming directly from our homes. Green hydrogen will be so limited in supply for the foreseeable future that it must be preserved for hard-to-electrify sectors such as steel.
To roll out heat pumps at the speed and scale required to limit the impacts of the climate crisis, the time for public investment to kickstart private investment is now or never. Yet funding announced this week will only support 0.3% of homes to choose a heat pump, with no support offered to most households for the necessary insulation and no additional support for low-income families.
The government is right to recognise that pumps are the future of clean heating, but the chancellor must deliver the full £12bn of funds needed to heat our homes efficiently, cleanly and fairly in next week’s spending review.
Unlike your letter-writer Gary Bennett, we didn’t just “search online”, we actually installed an air source pump, and it works brilliantly. We invested my retirement money not only in a pump but also the necessary insulation, underfloor heating and solar panels. The result is that we are paid for the excess electricity we now generate. If it was compulsory for every new house to have such a setup and proper grants were made available for older houses we might actually start to reach the targets set and see substantial financial returns by the end of the decade.
Holmfirth, West Yorkshire
Miles Brignall gives a useful summary of the costs of installing and running air source heat pumps (octubre 23), though there isn’t sufficient quantification: not many kWh in sight. But the practical difficulties and potential for higher running costs is well made.
Brignall also refers to the possibility of using hydrogen as a domestic fuel, dicho: “Hydrogen is the other great hope. Trials and schemes are testing whether the highly flammable element can be used safely.”
It would be useful for us all to remember that we have a century and a half’s experience of making, storing, distributing and using town gas: a hydrogen-rich mixture made by heat-treating coal, sometimes with steam. It was sufficiently well known to feature in the chemistry syllabus for A-level when I took the exam in 1963. The problems with hydrogen are largely about having enough zero-carbon electricity to make it cleanly by electrolysis of water.
Which raises another point. Even with projected efficiency improvements, moving the UK from fossils to electricity for cars and domestic heating (whether by heat pumps or hydrogen) will require a very high electricity generating capacity without burning coal, oil or natural gas, and also a huge energy storage capacity. This challenging aspect of going green is ignored in popular treatments, and gets insufficient attention in policy documents. The intermittency of solar and wind systems is well known, and other “zero-carbon” generation systems like carbon capture and storage are untested at scale. It is difficult to see how a robust and resilient carbon-free electricity can be achieved without new nuclear generators.