Every year about 130 million households across Europe burn almost 40% of the continent’s total gas consumption to heat their homes. Those boilers contribute more than a fifth of Europe’s greenhouse gas emissions in the process. Many have warned that the dominance of the humble gas boiler threatens to derail global climate targets, while keeping Europe reliant on gas imports and shackled to higher energy costs. For most European homes, the answer is likely to be an electric air source heat pump, as governments try to clean up carbon emissions. But not all households are convinced. In the UK, the plans to replace millions of gas boilers across the country with the little-known devices has fed into culture wars. There are those who believe heat pumps could play a vital role in climate action, and sceptics who claim their benefits are a lot of hot air. In between these binary positions stand millions of households with little clear information and high-stakes financial decisions ahead. In a series of articles, we will highlight the myths, the realities and the grey areas around the heat pump agenda. The first in our series asks: are heat pumps more expensive than gas boilers? It...