For decades, energy experts have been advising us that to save energy and protect the climate we need to improve the energy efficiency of our homes, and to do this we should apply a ‘fabric first’ approach. In other words, take steps to reduce heat loss from our buildings by increasing insulation, sealing draughts and fitting high-performance glazing. This seems intuitive; if a building is losing heat, we are wasting energy and money. And yet decade-long studies across multiple countries show that ‘fabric first’ delivers poor energy savings, marginal financial benefits and few carbon savings.

This is illustrated by the Warm Front scheme that helped up to three million households in England to install energy-efficiency improvements like loft insulation. A study of the scheme over ten years found a very positive outcome in that householders enjoyed more comfortable, warmer homes, but surprisingly the government money invested in the scheme did not result in lower energy use.

The reason is the ‘rebound effect’. When people can heat their homes affordably, they naturally seek greater comfort, heating their living space to higher temperatures and over longer heating periods, gaining better quality of life but wiping out any energy savings. In a nutshell, people choose comfort over energy savings.

Another factor is the law of diminishing returns. The greatest gains can be made by fitting the most effective measures – draught-proofing, loft and cavity wall insulation and double glazing. But thereafter each additional measure adds more expense with a diminishing return.

In contrast, electrifying everything comes with immediate 50% energy efficiency savings, vastly more than any other efficiency gains possible, according to heating expert, Michael Barnard of Clean Technica. For example, heat pumps are over four times more energy-efficient than a boiler. Electric cars are similarly more efficient than fuel-burning cars that waste more than half of their energy as heat.

Energy specialists now recommend an ‘electrification-first’ approach, as switching from a fossil fuel heating system to an electric heating system will immediately cut fossil fuel use, bringing greater climate benefits. They advise that a heat pump installed today becomes progressively greener as renewable electricity generation replaces fossil fuels in the grid. Conversely, however

well insulated, a home that continues to use gas or oil heating remains locked into fossil fuel dependency.

Difficult-to-insulate homes can be heated effectively with high-temperature heat pumps (HTHPs) that deliver heat at temperatures similar to gas boilers (60-80°C). This approach is cheaper and will reduce emissions more effectively than extensive retrofitting of the nation’s housing stock. Of course, new houses should be required to be all-electric to save their occupants energy and money from day one.

Improving the energy efficiency of our homes and buildings should support the goal of phasing out fossil fuels, not substitute for it. For householders, the message could be summed up as insulation and draughtproofing are beneficial but don’t take retrofitting too far and don’t use success there as an excuse to delay electrification when your heating system needs replacing.