Summer is no longer a pleasant exception in the UK. It is becoming a regular, sweltering occurrence. We are ill-equipped for it. Our houses were built for damp winters, not baking heatwaves. So, homeowners are panicking. They want solutions.
The trend? Heat pumps. Yes, those things you install for winter. Experts say they can cool you down, too.
Before you write them off as heating-only tech, let’s look at how they work as cooling systems. It’s not magic. It’s thermodynamics. And it might be cheaper than buying a dedicated air conditioner.
The Cooling Myth: Not All Heat Pumps Can Do It
First, clear the air. There are two main types of heat pumps: air-source and ground-source. Air-source pulls heat from outside air. Ground-source pulls it from the earth. Both can cool. But only if they are reversible.
“Not all heat pumps can provide cooling,” says Mark Parker, senior mechanical design engineer. “Many air-source and ground-source heat pumps do this if designed for reversible operation.”
You need to check your specs. Air-to-air heat pumps? Basically air con with a heater added. Air-to-water systems? They need compatible emitters. Radiators. Underfloor heating. Fan coil units. If your setup isn’t ready, the cooling won’t work.
Air-Source vs. Air Conditioning: Is There Really a Difference?
People confuse air con and air-source heat pumps. They shouldn’t.
“People don’t realise that when they buy Air Conditioning, they’re really buying a Heat Pump,” explains Adam Wilson of Furbnow. “An air-to-air heat pump is essentially Air Conditioning, and Air Conditioning is essentially an air-to-air heat Pump.”
The difference? One heats. One only cools. Unless it’s a reversible heat pump.
How does air-source cooling actually happen? Two ways.
1. Air-to-Air
It’s just air conditioning with a heating function. Blasts cold air directly into the room. Fast. Efficient.
2. Air-to-Water
This is trickier. It circulates chilled water through fan coil units or underfloor heating. The effect is gentle. Gradual. Not a blast of ice. But it maintains comfort without the dry, blasted feeling of standard AC.
“With underfloor heating, you can switch to cold mode,” says Wilson. “However, this is less common in the UK. Supply chain for installers is limited.”
Ground-Source: The Efficient Heavyweight
Ground-source heat pumps are rarer here. More expensive to dig. But they cool better in some ways.
Why? The ground stays cool in summer. Consistently.
“This allows some systems to provide highly-efficient passive cooling while using very little energy,” Parker notes. “Ground-source systems can also use the removed heat to recharge the boreholes or hot water.”
If you have the land, and the budget, the efficiency is unmatched. Passive cooling? That’s free energy savings.
Heat Pump vs. Air Con: Which Is Better for You?
Don’t just pick the first thing that blows cold air. Think about what you need.
Dedicated Air Conditioning:
– Rapid cooling in specific rooms.
– Better for intense heatwaves.
– Cheaper upfront if cooling is your only goal.
Reversible Heat Pumps:
– Gentle, year-round temperature control.
– Heats in winter, cools in summer.
– Versatile.
“If you want rapid cooling… a dedicated air conditioning system is generally better,” says Parker. “But for year-round heating with gentle cooling, a reversible heat pump is excellent.”
Portable units? Don’t even start. Those are cooling-only air con in a box. Installed air-to-air systems have outdoor units. Indoor wall units. Better circulation. Quiet. Discrete.
Maximising Your Heat Pump’s Cooling Power
Installing the tech is only half the battle. Design matters.
“The system must be properly designed and sized,” Wilson insists. “Room-by-room heat-loss calculations are required. Before installation. Always.”
Insulate. Seriously.
- Walls. Well insulated.
- Lofts. Check them.
- Glazing. Less is more.
- Shutters. External ones. Best for blocking sun.
“It’s a myth that your home needs to be perfectly insulated,” says Becky Lane of Furbnow. “But if you lose cold air easily, you need a bigger pump. Louder. Less efficient.”
The Verdict: What Type Is Best?
For most UK homes? A reversible air-to-water heat pump with underfloor heating or fan coils. It balances winter heat with summer cool without looking ugly.
If money is no object and you have a garden? Ground-source. Higher efficiency. Passive cooling benefits.
Air-to-air? Good for flats. Loft conversions. Places without radiators. Less disruption to install. Two pipes on the wall. Done.
“You don’t have all the pipework changing,” Wilson says. “Internal disruption is minimal compared to air-to-water.”
Cost: The Real Question
Here’s the hard truth.
Heat pumps are an investment. A big one.
£7,000 to £20k installed. Average £13k.
Boiler Upgrade Scheme takes £7.5k off.
Net cost? Around £5,500.
But you are paying for heating.
Air conditioning?
£1,500 to £13k.
Average £2.8k for a good installed system.
“Spending £13k on a heat pump mainly to cool is poor value,” Evans from Costwise warns. “£2.8k of air con could do the job.”
So, is it worth it?
If you want a home that heats itself for decades and cools in July? Yes. Heat pump. The grant helps.
If you just want to survive August without melting? Air con. It’s half the price. Does one job. Perfectly.
The heat pump revolution is here. But it’s not a silver bullet for cooling. Choose wisely.
