And yet, such systems do work and appear to be taking off in countries like the United States, where more than 40 per cent of new-build homes for single families come equipped with a heat pump, according to an International Energy Authority report last year.
They can even work in extremely cold climates such as northern Canada, although their effectiveness is understandably less than in warmer parts of the world.
While the IEA reported that electric heat pumps met no more than five per cent of global heating needs last year, it estimated that this figure could potentially rise to 90 per cent.
One of the main barriers preventing people from making the switch from gas to heat pumps is the high upfront cost of installing a new heating system. However, the lower running costs mean that this initial outlay can be recouped after a number of years, which sounds like an investment opportunity for an enterprising energy company. And there are also government grants available to help with the cost.
On the downside, a standard radiator will only reach between 40 and 45C with most air-source heat pumps, compared with 60 to 80C using a gas boiler, so radiators need to be bigger to provide the same degree of warmth.
But with gas boilers to be banned in new-build homes across the UK from 2025, this is a technology that is going to rapidly shift from apparent fantasy to everyday reality.