Heat pumps are the most efficient heating technology ever invented

The International Energy Agency is predicting a global explosion in the uptake of heat pumps. Their modelling, and that of other organisations, has identified heat pumps as the critical technology we need to get to net zero by 2050.

In an interview for the SwitchedOn podcast, Dr Jan Rosenow, Director of European programs at the global energy think tank, the Regulatory Assistance Project, says that’s because heat pumps “are the most efficient heating technology that we have ever invented.”

“They turn one unit of electricity into three, maybe four, even five units of heat. No other technology can do that.”

Even the most efficient gas boiler might get to 90% efficiency, but it can never get to more than 100%.

Heat pumps essentially transport pre-existing heat from one place to another, typically for heating or cooling. Water heat pumps extract heat from the surrounding air, ground or water and transfer it to heat the water stored in a tank, using an electric compressor.

Heat pumps designed for space heating extract heat from the outdoor air or the ground and transfer it into a building to provide heating, or remove heat from indoors and transfer it outdoors for cooling. This type of heat pump is commonly referred to as a reverse cycle air conditioner in Australia.

Europe saw a 40%expansion in the heat pump market in 2022 and a 30% expansion the year before.

“That was driven partly by policy. More and more countries in Europe have introduced support programs for heat pumps, but also regulation to phase out fossil fuel heating, especially in new buildings, but also increasingly in existing buildings.”

The uptake in heat pumps was also driven by a dramatic rise in the cost of gas because of the war on Ukraine by Russia.

Heat pumps have played a key role in the reduction of carbon emissions in Scandinavian countries where the uptake of heat pumps has been greatest.

‘In Finland, we have seen a reduction of 72% in carbon emissions from heating buildings over the last 30 years, more than 80% in Norway, and more than 90% in Sweden.”

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‍If we electrify everything, demand for energy will go down

Whilst he admits it may sound counterintuitive, Rosenow says there is good evidence to show that electrifying everything with efficient electrical appliances will drive the demand for energy down.   

“It would shrink the overall size of the energy system globally by about 40%. Just by electrifying end users to the full potential, we get a 40% reduction in final energy use,” he says.

That’s because new modern electrical appliances are so much more efficient than resistive electrical appliances or ones powered by fossil fuels.

Electric vehicles, for instance, are about three times more efficient than internal combustion vehicles. In other words, they use three times less energy to get the same amount of movement.

Heat pumps are even more efficient. “You might get maybe four to even five times more heat out of the heat pump compared to using the same energy in a fossil fuel boiler,”says Rosenow.

“In other words, you could say that electrification is energy efficiency.”

Energy efficiency crucial during the transition

Even though simply swapping out fossil fuel machines for electric ones, enables a more efficient use of energy, Rosenow argues we still need to reduce our energy demand as much as we can during the transition.

Modelling from the International Energy Agency, and other highly respected international organisations, like the IPCC, the International Panel on Climate Change, show that we will probably have to double, maybe even triple, electricity generation by 2050, if we electrify everything.

“That’s a huge challenge,” says Rosenow, so “anything we can do to reduce energy demand, by being less wasteful, will help make the problem smaller, make it easier for us to electrify.”

Rosenow is sceptical of the argument that we should just electrify everything and forget about energy efficiency during the transition. 

“I think that's a more expensive pathway, because you then have to find other ways of providing the needed energy.”

Those other ways would require batteries or another form of storage, which are more expensive than for example, insulating buildings. It would also mean a greater reliance for longer on a grid that still relies on coal generation in the case of Australia.

Rosenow identifies two areas where there is a huge potential to reduce energy demand – buildings and transport.  

“When you look at the amount of energy that is being used for heating buildings, at a global level, it's a tremendous amount. It's about a quarter of total energy use that we use for heat in buildings,” says Rosenow, “which translates into a similar amount of carbon emissions.”

That energy demand could be reduced not only by installing efficient electric appliances, but also by improving building insulation. 

“In many countries, buildings are terribly inefficient… there are very few countries where buildings are well insulated.” 

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Chicken or egg? Heat pump or insulate?

So should we properly insulate our homes – the roof space, walls, floor, install better windows and doors – before we invest in a heat pump for example?

“That's an argument I often hear, but I actually don't buy that,” says Rosenow, who says we should put in insulation regardless, and especially if we’re still using a fossil fuel heating system.

“If you have a well-insulated building, you can pre cool or preheat a building, and maybe do that, for example, when you have lots of solar generation,” says Rosenow.

“Then you need less electricity in the evening hours when the sun is set and there's no more solar generation available.”

Listen to the full interview with Dr Jan Rosenow on the SwitchedOn Australia podcast here.