Re your article (‘You can walk around in a T-shirt’: how Norway brought heat pumps in from the cold, 23 November), Norwegian homes are built to some of the highest standards in terms of their thermal performance, and have been for many years. Low heat-loss houses are ideally suited to the use of heat pumps – as well as other low‑energy/passive solutions – and so it should not be a surprise that the Norwegians have taken to the technology. Unfortunately, the UK has not been so far-sighted in terms of energy consumption, and so we have housing stock whose thermal performance is poor, meaning that adopting heat pump technology becomes a real challenge. Efficient heat pumps can help, but the answer to dramatically cutting the energy consumption of housing stock starts with the building structure, not the means of heating them. Just ask the Norwegians. Keith Crossley Manchester This is a nice article, showing Norway’s progress in installing heat pumps in a significant proportion of its homes. Two issues not mentioned are that heat pumps produce a lower grade of heat than gas boilers, which means that to get the same amount of heat into the house, a larger area of radiator is needed (or the house insulation needs to be significantly upgraded – another project that the British government is well behind on). Both are significant extra costs beyond the price of installing a heat pump. The other is an attractive freebie with heat pumps that is apparently not being offered – namely that it would cost very little to allow the heat pump to run in reverse and give free cooling on hot days. Nick Lumb Wrexham