Air Conditioning Contractors

Heating your home

Air Conditioning

Air-to-air heat pumps transfer heat from the outside air to the air inside your home, increasing the air temperature in each room. This warm air enters your home through a series of fan coil units, or ‘blowers’.

Air-to-air heat pumps are sometimes referred to as air conditioning. While many people think of air conditioning as a way of cooling buildings, it can also be used for heating.

Most air-to-air heat pumps don’t heat water delivered to the taps. You may need to consider an alternative way of heating water for showering and bathing.

Is an air-to-air heat pump right for me? 

In the UK, air-to-air heat pumps aren’t typically used for heating larger homes. are most common in the UK. More often, air-to-air heat pumps are installed in smaller properties, such as flats and park homes.

Elsewhere in Europe, air-to-air systems are more common. This is partly because they can be used for cooling as well as heating, which is especially useful in warmer climates.

There are a few things to consider when deciding whether an air-to-air heat pump is right for you.

How will I heat my water?

You’ll need an area outside your home for a unit to be fitted to a wall or placed on the ground near the house. It needs plenty of space around it to get a good flow of air.

How will I heat the rooms in my home?

Most UK homes use radiators or underfloor heating to distribute heat to each room. These are commonly referred to as ‘wet’ heating systems. One advantage of air-to-air heat pumps is that they don’t need a wet central heating system to warm the home.

An air-to-air heat pump uses either blowers or air ducting pipes to deliver warm air. Blowers are usually mounted high on the wall, which can be helpful where wall space is limited. Ducting systems are more likely used in new build properties as the ducts are typically mounted inside the ceiling voids to make them less intrusive.

The number of blowers used in an air-to-air system is known as its ‘head’. Air-to-air heat pumps can be either:

Single-head: a single outside unit and a single blower inside.
Multi-head: a single heat capture unit outside and multiple blowers inside.

Generally, single-head air-to-air heat pumps installed in the UK are only used in the smallest homes, or for single room heating. If you have more than two rooms, you likely need multi head air-to-air heat pump or a ducted system.

As there’s no need for a wet central heating system, air-to-air systems using blowers can be relatively quick and cheap to install. Multi-head installations need to have pipes travelling from the outside heat capture unit to each blower. This is similar to boilers needing pipes running to a radiator in each room.

Typically, these pipes run in a slim plastic channel around the upper edges of the room to keep them as unobtrusive as possible.

How will I heat my water?

Most air-to-air heat pumps don’t heat hot water, so you may need another way of heating water for showering, bathing and hot taps. You need to consider the amount of hot water your household needs and any space or budget considerations. Options include:

using a hot water cylinder fitted with an
installing an electric shower or ‘point of use’ water heaters.
choosing an air-to-air heat pump model that does provide hot water.

Point of use heaters tend to use either gas, LPG or electricity to heat the water. Electric heating units can simply be mounted underneath the sink out of sight. However, if you have a gas-fired heater, you will also need to install a flue.

Will an air-to-air heat pump save me money?

Running costs depend on how your heat pump is designed and how it’s operated. Savings on your energy bill are also affected by the system you’re replacing.

There’s currently little independent data on how air-to-air systems perform in the UK, so it’s difficult to predict how much money you’d save by fitting one. However, we can give some general guidance on what to expect.

Saving money on fuel bills isn’t everyone’s primary motivation for installing a new heating system, but you need to be sure you can afford to run the system once installed. Ask your installer for an indication of running costs based on their design of the system for your home.

Installing and siting the blowers

The pipes running to the blowers are all connected to the outside unit. For this reason, blowers are often installed on the inside of an exterior wall near the outside unit to reduce the length of piping you need inside.

With multi-head systems, the installer normally aims to minimise the length of piping to each blower location. So, before the installer starts work, ask anyone surveying your house about the possible pipe routes.

Installing ducted systems

Ducted systems are typically used in energy efficient houses such a Some types of ducted systems are referred to as (EAHPs), though EAHPs can also supply hot water.

Air can’t carry large amounts of heat in the same way that a wet central heating system can, so ducted systems may not be suitable for older or larger houses with a high heating requirement.

The ducts used by installers are designed to allow large volumes of air to move around the house through pipes that are slim enough to be hidden inside the ceiling voids. All that’s visible inside each room is two grills mounted in the ceiling: one for flow in and one for flow out of the room.

The air is warmed in an air handling unit, which is roughly the size of a boiler and is normally installed in a loft or utility room.