Air Source Heat Pump Pros and Cons

Your Heating Bill Could Drop by £700+ a Year

A typical 3-bed semi uses 12,000kWh of gas per year. At the current Ofgem rate of around 7p/kWh plus standing charges, that's roughly £985 per year on heating. Replace that with a SCOP 4 air source heat pump and the demand reduces to 3,000kWh of electricity. On a time-of-use tariff at 9p/kWh, that costs around £270 per year. Remove the gas supply entirely and the net saving is £700–£750.

These figures assume a gas boiler running at 90% efficiency, which is best case. Most boilers operate at 80–85%, meaning real costs are higher and the savings from switching is greater. Most households aren't on a time-of-use tariff either, so moving to one as part of the switch adds further savings on top.

For homes on oil or LPG, where fuel costs are higher and more volatile, the savings are greater still. Our air source heat pump cost and savings guide covers full pricing by property size.

300–400% More Efficient Than a Gas Boiler

A gas boiler converts 1kWh of gas into roughly 0.9kWh of heat. An air source heat pump converts 1kWh of electricity into 3–4kWh of heat, measured as a Seasonal Coefficient of Performance (SCOP) of 3–4.

This is because an ASHP doesn't generate heat from scratch. It moves existing heat from the outdoor air into your home using a refrigerant cycle, which takes far less energy than burning fuel. It's this efficiency that makes running costs lower despite electricity costing more per unit than gas.

The Grant Could Bring Your Cost Down to £1,000

The Boiler Upgrade Scheme (BUS) covers up to £7,500 when replacing a gas or electric heating system, and up to £9,000 when replacing oil or LPG.

For example, a system costing £10,000 with a £9,000 BUS grant brings the out-of-pocket cost down to £1,000. Elite Energy are MCS-accredited and apply the grant directly to your invoice, so the discount comes straight off the price.

No Gas Bill, No Standing Charge

Switching to an ASHP means you can disconnect from the gas supply entirely. That removes the gas standing charge (around £100 per year) on top of the fuel saving, and takes you off a fuel market you can't control.

For homes on oil, it also means no more fuel deliveries, no fluctuating oil prices, and no storage tank on your property.

Cuts Your Heating Emissions

A gas boiler produces around 2,500kg of CO₂ per year. An air source heat pump produces around 850kg, roughly a third of the emissions for the same heating output. Over a 20-year lifespan, that difference adds up to over 30 tonnes of CO₂ kept out of the atmosphere.

As the UK electricity grid continues to decarbonise, the carbon footprint of running an ASHP drops with it.

Heating and Cooling From One System

Unlike a boiler, some ASHPs can reverse their cycles in summer to provide cooling. Not every model supports this, but many modern systems offer it. One system, two functions, and no need for a separate air conditioning unit.

Less Maintenance, Twice the Lifespan

An ASHP just needs a yearly service. No annual Gas Safe inspection, no combustion parts, no flue to maintain. Fewer things to go wrong and lower ongoing servicing costs than a gas boiler.

A well-maintained system lasts 20–25 years, roughly double the 10–15 year lifespan of a typical gas boiler. Over that period, you'd likely replace a gas boiler twice for the same coverage one ASHP provides.

Safer Than a Gas or Oil Boiler

No combustion means no risk of carbon monoxide poisoning and no risk of a gas or oil leak. For homes on oil, switching also removes the storage tank from your property, eliminating the risk of tank leaks and fuel spills.

ASHPs run on electricity and refrigerant in a sealed system. Nothing burns, and nothing can leak into your home.

Improves Your EPC Rating

Switching from gas or oil to an ASHP typically lifts your EPC by one to two bands (for example, D to C, or C to B). This matters for property value, green mortgage eligibility (lenders offer preferential rates for EPC C+), and future lettings regulations.

Higher Upfront Cost Than a Boiler

ASHP installations cost £8,000–£18,000 depending on property size, compared to £2,000–£4,000 for a gas boiler replacement. It's a significantly larger outlay.

The BUS grant (£7,500–£9,000) closes much of the gap, and finance options are available through most installers including Elite Energy. A system costing £10,000 with a £9,000 oil/LPG grant brings the out-of-pocket cost down to £1,000. But even with support, it's a bigger commitment than a boiler swap.

You'll Need Space for a Hot Water Cylinder

Unlike a combi boiler, an ASHP heats water to a lower temperature and stores it in a cylinder rather than heating on demand. For homes that removed their hot water tank and airing cupboard when switching to a combi, this means finding space for one again.

This is a genuine inconvenience, particularly in smaller properties. Slimline cylinders and alternative locations (utility rooms, garages, understairs cupboards) can help, but it's a factor worth considering early. Your installer will assess space options during the survey.

The Outdoor Unit Can Be Bigger Than Expected

The outdoor unit is roughly the size of a large suitcase or small chest freezer, and it needs clear space around it for airflow. It produces a low hum when running, typically 40–50 decibels, comparable to a fridge or a quiet conversation.

Some homeowners don't want a visible unit in their garden. Screening with fencing or planting can reduce the visual impact without restricting airflow, but the unit will be there.

Security is another concern that comes up regularly. Modern units weigh 60–80kg and can be secured with anti-theft brackets and cages. Theft is uncommon, but if it's a worry, your installer can advise on securing the unit properly.

You May Need to Upgrade Your Radiators

ASHPs run most efficiently at flow temperatures of 35–45°C, lower than the 60–80°C a gas boiler produces. This means the heating system runs at a gentler temperature for longer periods.

In homes with modern radiators or underfloor heating, this works well. In older homes with small, single-panel radiators, some may need upgrading to larger double-panel models to deliver the same comfort level. Elite Energy assesses this during the survey and handle radiator upgrades as part of the installation when needed.

Efficiency Drops in Sustained Extreme Cold

ASHP efficiency reduces as outdoor temperatures fall below 0°C. Below -5°C, the system works harder and the defrost cycle runs more frequently, increasing electricity consumption.

In most of England, sustained temperatures below -5°C are rare. Modern ASHPs are rated to operate down to -20°C or -25°C, and across a typical UK heating season, cold weather performance is not a practical concern for the majority of homes.