How to Construct a Concrete Base for Heat Pumps

If you’re thinking about installing a heat pump, especially an air source heat pump, one thing you can’t overlook is the base it sits on. A strong and level foundation helps the system work properly and last longer. At Concrete in Cornwall, we help homeowners and installers across the region get their bases right before installation begins. Here's what you should know about concrete bases.

​Why the Right Base Matters

Your heat pump isn’t just another garden appliance it’s a fairly heavy and important bit of kit that needs to be kept stable and level at all times. A proper concrete base helps to reduce vibrations, protect the unit from frost or standing water as it keeps the unit raised above ground level. Most manufacturers clearly state that a solid base is needed for their warranty to be valid, so skipping this step could cost you down the line.

​How Big Should the Base Be?

There isn’t one standard size because heat pumps come in different shapes and sizes, but we recommend the base be at least:

• 30cm wider and deeper than the unit
• 10 to 15cm high (100–150mm)

So if your heat pump is one metre wide and half a metre deep, you’ll want a base that’s about 1.3 metres wide and 0.8 metres deep. This gives enough space for airflow, stability, and any maintenance that might be needed later on.
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That said, always check the specific instructions from your heat pump’s manufacturer. Some may need even more clearance or different installation guidelines.

​Where Should You Put the Base?

Location matters just as much as size. You’ll want the base to be:

• On flat, level ground
• Around 1 metre from your property boundary (in England and Scotland)
• Away from windows or bedrooms to minimise any noise
• Placed where it won’t spoil the look of your property from the road

If your property is in a conservation area or near a world heritage site, or if it’s a listed building, then extra rules may apply. It’s best to check with your local planning authority before laying any concrete or ordering the pump. If your based in Cornwall like us check out Kozy Koala for renewable energy systems.

​What Concrete Mix Should You Use?

To make sure your base lasts and holds up against the stormy Cornish weather, we usually recommend a C25 strength concrete mix. It’s a strong, reliable option commonly used for small foundations and outdoor pads.
A good general mix ratio is:

• 1 part cement
• 2 parts sharp sand
• 4 parts crushed stone or gravel

This gives you a solid, durable base that can take the weight of your heat pump and deal with years of exposure to the elements. If you’re not sure about mixing it yourself, we can supply ready-mix concrete to your site, just give us a shout.

​A Good Base Means a Great Start

Getting the base right is a small job that makes a big difference. It helps your heat pump stand strong, keeps it protected from the elements, and makes sure you stay on the right side of installation requirements. At Concrete in Cornwall, we know how important a strong base is to a successful heat pump installation. Whether you’re working with a professional or tackling it yourself, we’re here to help with the right concrete mix and friendly advice along the way. If you're planning a project, just give us a call. We're always happy to chat concrete, help with mix ratios, or arrange delivery anywhere in Cornwall.