A heat pump works in a very different way to a gas boiler and so, if you’ve decided to make the switch, there are a number of things that you need to consider. For instance, a boiler goes inside your home, whereas a heat pump unit is usually located outside. You may also want to consider how a heat pump could affect your home in other ways. For example, you might benefit from increasing the amount of insulation in your home and potentially even installing solar panels so that the heat pump can run on renewable energy.
One thing you will certainly need to consider is where the main unit will go in order for it to run at maximum efficiency. Generally, you should be able to pick an ideal location and the pump will be able to go there, however, there are some things that could prevent a pump from being put where you want it.
The perfect location for a heat pump may depend on whether it’s an air source or ground source variety.
An air source heat pump requires good air flow in order to work at its most efficient. This is because it draws air in through the sides and the back of the unit and then allows cold air to exit from the front once the heat has been extracted. Ground source heat pumps take heat from the ground instead, and so the pump unit can actually be installed in your home. Find out more about where to locate a ground source heat pump later on in this post.
Ideally, an air source appliance should be situated in a place that isn’t too hemmed in. For instance, one side of your house may have a narrow alleyway but the other side may be mostly garden. It would be more beneficial to place it on the garden side and not in the narrow alleyway. Any plants or shrubs that may be located near your heat pump should be at least a metre away. You need to ensure that these are cut back regularly in case they begin to encroach upon the site.
The pump should also be installed in a place that’s easy to access for services and other general maintenance. You don’t want it to be in a position that’s difficult to get to or that requires scaffolding or ladders in order to reach it. For this reason, it’s best located on the ground at the back of a property. This location also allows for pipework to be kept to a minimum, making the system more efficient. If you’re unable to have it installed directly on the ground, it can be hung on brackets a few inches above the ground.
As well as these general points, there are some regulations that must be followed. A suitably qualified heating engineer should be able to advise you on these points prior to installation.
The heat pump should be at least one metre away from any site boundary and units installed on a flat roof should be at least one metre away from the roof’s edge. Planning permission may be required if your home is a listed building and for homes in conservation areas or World Heritage Sites, the pump should be installed at ground level.
You should always read the manufacturer’s manual to ensure that the heat pump is being installed in the best place. This manual will also outline any regulations that should be adhered to.
Keeping all of the above in mind, there are limited places where you can put your air source heat pump. Generally, any outside wall on your house can be suitable as long as there’s enough space for the pump to take in air and you’re not breaching any local planning or building regulations, this may also include noise output (dB(A)) of the unit.
You cannot locate an air source heat pump in the house. As previously described, these units allow the cold air to exit once the heat has been taken out. This would essentially turn any room in your home into a fridge. As the air around the pump becomes cooler, it will need to work much harder to extract the heat from it - until it’s almost impossible. This would not be a very efficient way to heat your home, and so an air source heat pump must be placed outside.
Unlike an air source heat pump, ground source systems take in heat from the ground via a series of pipes that are installed around your property. For homes that have less land, the pipework can be laid vertically instead of horizontally. As they don’t require an airflow and don’t expel the cold air, these appliances can go in your home. They can be quite large, so a cellar or utility room might be a good place for one.
In order for a ground source heat pump to work efficiently, the pipework needs to be a particular length so it can gather the necessary heat and take this to your home. A standard eight kW heat pump needs around 250 m2 of land for pipework to be laid. The average sized garden in the UK is around 163 m2. Luckily, with the vertical installation system, boreholes can be drilled down to 100 m and deeper so that not as much land is needed. Typically for the above 8 kW heat pump, you might need 2 boreholes around 60m deep. So long as the drilling rig can access the site, you’ll have enough space for a ground source heat pump.