What size heat pump do I need?

If you’re thinking of going low carbon with a heat pump, you might have started to do some research on what size heat pump is right for your home. In this guide, we’ll explain what factors affect the size of heat pump you need – and help you calculate what size heat pump is right for your home.

How big is an air source heat pump?

The size of a heat pump usually refers to its power output, not its physical size. As with boilers, heat pumps come in a range of power outputs – from 5kW models to 16kW models.

More powerful heat pumps do tend to be physically bigger as well, but not by much. The two examples below give you an idea of how the physical size might vary between heat pumps.

Is it important to get the right size heat pump?

Yes, absolutely. Just like with gas boilers, getting the right size heat pump will help keep your home comfortable and your bills low.

The more heat your home needs, the more powerful your heat pump should be. A heat pump that’s too small won’t be able to effectively supply all your heating and hot water. And a heat pump that’s too big won’t be efficient.

How do I choose the right size heat pump for my home?

Luckily, this is very simple. A British Gas technical surveyor will look at your home, room by room, to calculate how much heat is needed to keep every area comfortable. We’ll also look at your hot water demand, then recommend the right size heat pump for your home.

What factors affect the size of my heat pump?

Every British Gas heat pump installation begins with a free home survey. As well as making sure your home is suitable for a heat pump, we’ll look at all the different factors that affect how powerful a heat pump you’ll need.

As well as the size of your home and your family, we’ll also look at how much heat is lost, especially through the roof, walls and floor. The slower the heat escapes your home, the less it has to be replaced by your heat pump. That’s why insulation is key to getting the best from a heat pump.

Here are the factors your surveyor will typically look at when deciding what size heat pump you need:

  • The size of property and the size of your rooms
  • The building materials used for your walls and floor
  • The level of insulation in your roof
  • What kind of windows you have (single, double or triple-glazed)
  • Location (colder areas of the country will need a bigger heat pump than warmer ones)
Learn more about Air Source Heat Pumps