Energy-efficient heat pumps have been heralded as one of our greatest weapons in the worst energy crisis since the 1970s. By installing one of these devices, homeowners can play their part fighting climate change and in helping Europe eliminate its dependence on Russian fossil fuels.

The biggest lure for consumers heeding the Government’s heat pump promotion that used grants as incentives was the promise of lower heating bills. But instead of finding themselves insulated from the skyrocketing bills being received by households who rely on oil and gas, many homeowners are now blaming their heat pumps for higher-than-expected electricity bills and taking toFacebook groups to express their shock at bills that have – in some cases – exceeded €1,000 for just two winter months.

Are heat pumps really responsible for driving up your electricity bills? If so, what can you do about it?

What is a heat pump?

Heat pump technology is not a new concept: the British physicist and engineer Lord Kelvin proposed using heat pump systems for space heating as far back as the 1850s. A heat pump works like a fridge in reverse. Instead of cooling its contents and emitting some heat in the process, a heat pump uses a refrigeration cycle to extract heat from the outside environment – air, water and land – and releases it into a building. That heat is transferred to the water in your heating system, including radiators and underfloor heating, as well as to your hot water tank. Heat pumps can also provide cooling when it’s hot in summer.

Higher electricity prices drive up costs.

Heat pumps are more efficient than other heating systems because the amount of heat they produce is more than the amount of electricity they use. But consumers could not have foreseen that this electricity used would surge in price during an energy crisis, says Professor Aoife Foley, an expert in energy systems engineering at Queen’s University Belfast.

Mike Teahan from Renewable Building Solutions, who has been supplying and designing heat pumps for 20 years, says there are myriad reasons why heat pump running costs can increase and that it’s always never the fault of the heat pump itself.

“I get phonecalls every day from people saying their bills have doubled since last year,” he says. “When they ask why they are getting a bill of €800 for just two months, you have to explain that the cost of electricity has gone up by two-and-a-half times. If electricity more than doubles in price, so does the cost of running a heat pump.

“The cost of electricity has gone so high that heat pump running costs are probably the same as running a decent gas boiler. Gas prices have gone up, but not to the same dramatic effect as electricity. Until energy companies bring down prices, many people won’t be able to afford these bills.”

While wholesale energy prices have been falling on international markets over the last few months, Pinergy is so far the only electricity provider in the Irish market to announce it will cut prices for residential customers. Owners of heat pumps should be prepared for a long and bumpy ride: electricity prices could remain above pre-Covid levels for the next five to seven years, Foley says.

Get your settings right

Homeowners accustomed to gas or oil-fired central heating should resist the temptation to turn off their heat pump system when they are leaving for work, for example, so as to save energy. That’s because heat pumps work best when they are continuously on, says Brian McIntyre, programme manager at the SEAI’s High Performance Building Technologies unit.

“People might think ‘there’s an energy crisis and I don’t want to use more electricity,’ but by turning it off and on you might use more electricity because heat pumps tend to work better when they are left on,” he says.

“A plane uses most of its energy during take-off and landing and a heat pump is like that. If you’ve turned off thermostat when it was at 19C, you will use a lot of electricity to bring the house back up to 19C.”

By leaving the thermostat on at 19C or 20C, instead of 21C or higher, you’ll use fewer units of electricity. And just as you would be mindful of your appliance usage during the crisis with a traditional fossil-fuel based system, you should be careful when using energy-heavy appliances such as a tumble dryer or oven, says Foley, who has been involved in the Government’s ‘Reduce Your Use’ campaign to address the energy crisis.

“No matter what type of heating system you have, treat it as if it’s expensive,” she says. “Monitor your consumption, set the thermostat to 19C, and put on a pair of socks and a jumper, because the next seven years is going to be a rollercoaster.”

Get problem-busting

Assuming that your home is insulated and airtight enough for your heat pump to work efficiently, your electricity bills could be higher because a building contractor or installer hasn’t installed or commissioned the system properly.

“The majority of heat pumps are installed really, really well, but you always hear about the bad cases where a heat pump is costing someone a fortune and now their contractor wouldn’t answer the phone to them,” Teahan says.

“I’ve seen installations that would frighten you, such as the heat pump being far too big for a house. It could be that the contractor mightn’t understand the system and doesn’t know how to sort out the problem and won’t answer the phone because he’s putting his head in the sand. The underfloor heating might not have been sized properly, the pipework going to the heat pump could be too small, the radiators could be the wrong size, or the heat pump itself might be too small for the house.

“You should have received a handover pack with the system commissioning details, with who installed it, and who supplied it. Your first port of call should be to the person who installed it. It could just be a dirty filter or a simple error. If something is wrong with the heat pump itself, he’ll contact the supplier to send someone out.

“Ask your supplier if the heat pump has been commissioned properly. Certain companies out there are very good and will insist it be commissioned and signed off and will hand you over the paperwork. But a lot of companies out there just sell heat pumps in a brown box and won’t do that. Then people get an electricity bill for €2,000 and say, ‘oh, it’s the heat pump’s fault’. But it’s just that the heat pump has been used in an incorrect manner.”

'Although Ireland generates around 35pc of its electricity from renewable sources, we're still reliant on gas and other fossil fuels,' says Switcher.ie's Eoin Clarke

Pump up those bills

The average annual cost of running an air-source heat pump in a typical Irish household is now almost the same as using gas or heating oil as wholesale oil and gas prices fall and retail electricity prices remain high, figures compiled for the Sunday Independent by Switcher.ie indicate.

The yearly cost of using a heat pump is an estimated €1,557.50, compared to €1,593.07 for a house run on heating oil and €1,524.60 for a home run on gas, according to calculations by Eoin Clarke at Switcher.ie that were based on electricity and gas prices on a standard meter 12-month contract from Electric Ireland (including the discount for direct debit and online billing), kerosene prices, and on usage statistics from the Commission for Regulation of Utilities. However, bills for owners of heat pumps are the total for all their energy needs, as they do not have to pay extra for heating oil or gas. The estimated household cost of electricity is now €1,717.38 a year.

"Households saw both gas and electricity rates soar thanks to rapidly rising wholesale gas prices last year,” Clarke says. “Although Ireland generates around 35pc of its electricity from renewable sources, we're still reliant on gas and other fossil fuels for most of our electricity. The good news is that it appears wholesale gas prices are tumbling and the energy shocks of 2022 should be behind us. It could be a while until consumers see price drops reflected in their bills, but with warmer months and the continuation of Government interventions like the VAT reduction, the burden is easing.”