Do I need a concrete pad for my heat pump?
Yes, you'll need a solid base for your heat pump - a concrete pad is the most common choice. Heat pumps are fairly heavy units and they vibrate when running, so a proper foundation keeps them stable and cuts down on noise.
A concrete pad works best because it's level, solid, and won't shift over time. You can use paving slabs if they're thick enough and properly laid, but concrete is usually worth the extra effort. Make sure it's slightly larger than the unit itself and perfectly level - even a small wobble can cause problems down the line.
The base also helps with drainage and keeps the unit off the ground, which prevents moisture issues. Most installers will sort this out as part of the job, but it's worth checking what's included in your quote. A proper base might seem like a small detail, but it makes a real difference to how quietly your heat pump runs and how long it lasts.
Interested in more details?
Do You Need a Concrete Pad for Your Heat Pump?
If you're installing an air source heat pump, you're probably wondering whether you need to lay a concrete pad. The short answer is yes – most ground-mounted heat pumps require a solid, level base, and concrete is the most reliable option. However, there are a few alternatives worth considering depending on your situation.
Why Your Heat Pump Needs a Proper Base
Heat pumps are hefty pieces of kit, typically weighing between 70-150kg. Without a stable foundation, your unit will vibrate, shift, and potentially cause all sorts of problems. A concrete pad serves several crucial purposes:
- Prevents vibration noise – Nobody wants their heat pump humming and rattling at all hours
- Keeps the unit level – Essential for proper refrigerant flow and drainage
- Protects against settling – Soft ground can shift over time, throwing your system out of alignment
- Improves longevity – Less stress on components means fewer repairs down the line
Concrete Pad Specifications
Your concrete pad should be roughly 100-150mm thick and extend about 150mm beyond the heat pump's footprint on all sides. For most domestic units, you're looking at a pad around 1.2m x 0.8m, though larger systems need bigger bases.
The concrete needs time to cure properly – at least 7 days before installation. You'll also want to include a slight slope (about 1:100) to ensure water drains away from the unit rather than pooling underneath.
Cost Expectations
A professionally poured concrete pad typically costs £200-400, depending on size and local labour rates. If you're handy with DIY, materials alone might run £50-100, but remember that getting it level and properly cured is crucial for your heat pump's performance.
Alternatives to Concrete
Whilst concrete is the gold standard, you do have other options:
- Composite plastic pads – Lighter and easier to install, costing £150-300. These interlock and provide good stability
- Paving slabs – Multiple thick slabs can work if properly levelled on a sand/cement base
- Gravel with reinforcement – Sometimes acceptable for smaller units, but check manufacturer requirements
Wall-mounted heat pumps obviously don't need ground-level bases, but your wall structure must be solid enough to handle the weight and vibration. Most installers prefer ground mounting for easier maintenance access.
UK Building Regulations and Planning
Under permitted development rights, most heat pump installations don't need planning permission, but your base must comply with building regulations. The pad should be considered a permanent structure, so proper drainage and foundation work matters.
Some areas have specific noise requirements – particularly important since a wobbly heat pump on an inadequate base will be much noisier than one properly mounted on concrete.
Common Mistakes to Avoid
Many homeowners underestimate the importance of proper preparation. Simply plonking a heat pump on bare ground or a few bricks will lead to problems. The unit will shift, pipes may strain, and you'll likely void your warranty.
Another frequent error is making the pad too small. That extra 150mm around the edges isn't just for show – it provides stability and prevents edge cracking under the unit's weight.
Installation Tips
Most heat pump installers will include base preparation in their quote, which is often your best bet. They know exactly what's needed and can coordinate the concrete work with the installation timing.
If you're doing groundwork yourself, ensure you've called utility companies to mark underground cables and pipes. The last thing you want is to hit a gas line whilst digging your foundation.
Remember that access for maintenance should influence your base location. Your engineer will need to reach all sides of the unit, so don't squeeze it into a tight corner just because the concrete work seems easier there.