Air-to-air and air-to-water heat pumps both pull heat from the outside air, but they deliver it to your home in very different ways. Choosing the right one depends on what kind of heating system you already have, whether you need hot water too, and whether you want to access government grant funding. Here’s how they compare, and why we install air-to-water systems as standard at AN Heating.
What’s the Difference Between Air-to-Air and Air-to-Water Heat Pumps?
An air-to-air heat pump warms your home by blowing heated air directly into rooms, similar to how air conditioning works in reverse. An air-to-water heat pump heats water instead, which is then circulated through your radiators, underfloor heating and hot water cylinder, working with the wet heating system most UK homes already have.
How Air-to-Air Heat Pumps Work
Air-to-air systems use indoor wall-mounted units, a bit like air conditioning units, to blow warm air into a room. They’re often quick to install and can also provide cooling in summer. The downside is they don’t heat your hot water, and because they don’t connect to a wet heating system, they usually only heat the specific rooms with a unit fitted rather than your whole home evenly.
How Air-to-Water Heat Pumps Work
Air-to-water systems connect to your existing radiators or underfloor heating and your hot water cylinder, much like a boiler does. This means the whole home is heated the way you’re used to, and you get your hot water from the same system. It’s why air-to-water is the more common choice for a full central heating replacement, and it’s the technology we specialise in installing, including Worcester Bosch’s 7001iW air-to-water heat pump.
Can You Get a Grant for an Air-to-Air Heat Pump?
No, not currently. The government’s Boiler Upgrade Scheme applies to air-to-water and ground source heat pumps that replace a fossil fuel heating system, not air-to-air units. If accessing grant funding matters to you, an air-to-water heat pump is the route that qualifies.
Which Type Heats Your Hot Water Too?
Only an air-to-water heat pump heats your hot water as part of the same system. An air-to-air heat pump only heats the air in a room, so you’d still need a separate way to heat water for your taps and shower.
Which Type Suits Older or Period Homes?
Air-to-water heat pumps tend to work well in period and older properties, provided the property has reasonable insulation and, ideally, larger radiators or underfloor heating to help the system run efficiently at lower flow temperatures. Air-to-air systems can suit a single extension, garden room or an area without existing central heating, but they’re rarely the right fit as a whole-home replacement.
Making the Right Choice for Your Home
A few questions help point you in the right direction:
- Do you want to replace your whole heating and hot water system, or just heat one room? Whole home points to air-to-water, one room may suit air-to-air
- Do you want to apply for Boiler Upgrade Scheme funding? Only air-to-water and ground source systems currently qualify
- Do you already have radiators or underfloor heating in place? Air-to-water makes use of what you’ve got
- Do you want cooling as well as heating? Some air-to-air systems offer this, air-to-water systems are primarily for heating
Common Questions About Air-to-Air and Air-to-Water Heat Pumps
Is an air-to-water heat pump more expensive than air-to-air?
Generally yes, because it’s a bigger job that replaces your whole heating and hot water system rather than heating a single room. Grant funding through the Boiler Upgrade Scheme can offset this for air-to-water systems.
Do air-to-air heat pumps work in the UK climate?
Yes, modern air-to-air heat pumps perform well in UK temperatures. Their main limitation isn’t the climate, it’s that they only heat the rooms they’re installed in and don’t provide hot water.
Can I have both types installed?
It’s possible, though most homeowners choose air-to-water for whole-home heating and only add an air-to-air unit for a specific space, such as a garden office, that sits outside the main heating system.
If you’re weighing up which heat pump suits your home, our team can talk you through the options honestly, including whether you’d qualify for grant funding. Find out more about our air-to-water heat pump installations. We install and service heat pumps across Trowbridge, Melksham, Westbury, Frome, Warminster and Chippenham.