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Air Source Heat Pumps

If you have an air source heat pump at your home, or are having one fitted, you may have some questions about how it works and how to use it effectively. Hopefully, our frequently asked questions will provide you with everything you need to know.

If you require more information, please contact our Energy team by emailing:

How do air source heat pumps work?

Air source heat pumps work in a very similar way to a fridge or freezer. A mixture of water and antifreeze travels around a loop of pipe contained in a unit located on the exterior of your home. Heat from the external air is absorbed by the fluid as it passes through the pipe and back into the heat pump itself.

To provide you with heating and hot water, the heat pump increases the temperature of the liquid to an acceptable level by compressing refrigerant gasses and using the resultant heat to warm the liquid further. The heat pump uses a heat exchanger to transfer the heat to the heating circuit of your home.

Should I ever turn the air source heat pump off?

No. Heat pumps should never be turned off completely. This is because they will be expensive when turned back on as they will try to raise the temperature as quickly as possible. It can also take several days to restore the home to a comfortable temperature.

How should I adjust my heating?

  • At night? Lower the temperature to around 10-15°C on your thermostat, and then set it to slowly increase in the morning so that the room is a comfortable temperature when you wake up.
  • Away for a day? Just leave the system running as usual, the systems are designed to work most cost effectively when running constantly in the background.
  • Away for a week or longer? The system should have a ‘holiday’ or ‘frost protection’ setting on the control panel, which will lower the room temperature while you are away. This will also prevent the pipes freezing if you are away during cold weather.
  • During the summer? Your heat pump might have a ‘summer’ mode, or you can simply turn down the room thermostat. This means the heating will not come on, but you will still get hot water. You can raise your heating temperature again slowly as the autumn approaches.

What tariff should I be on if I have an air source heat pump?

Air source heat pumps require electricity. Some electricity providers offer an air source heat pump tariff, so it’s a good idea to speak to your provider and enquire if this is available. These tariffs offer cheaper unit rates for homes with heat pumps, as well as rate reductions during specific times of the day.

Meters: In general, the most cost-effective way to run a heat pump is on a single-rate tariff, rather than Economy 7 (where you have cheaper night electricity, but it’s more expensive during the day). Your electricity company can advise on which tariff suits your usage.

Will my air source heat pump work in all weathers?

Even in minus outdoor temperatures, there is energy in the air for the heat pump to convert. There is even energy all the way down to -273°C (absolute zero). Most industry air source heat pumps operate at nearly full efficiency at temperatures as low as -10°C.

Are air source heat pumps safe?

Air source heat pumps are a safe, tried and tested technology. The system contains no harmful gas emissions and no flammable oil, Liquid Petroleum Gas or gas pipes. There’s no unsightly fuel storage and no flues or chimneys required for air source heat pump installations.

Are air source heat pumps effective?

Yes, air source heat pumps are a very effective way of heating homes year-round. While outside air temperatures can affect the efficiency they operate at, air source heat pumps can operate in even extreme cold weather. Generally, the warmer the air is outside, the more energy-efficient your pump will be.

What to expect during your air source heat pump installation

  1. Dust – We try to minimise dust, but it is unavoidable. Dust sheets will be used around the property to protect your belongings.
  2. Drilling – There may be noise produced throughout the installation.
  3. Materials – There will be materials around the area the installation team are working in. We aim to keep to these to a minimum and your property will be left tidy at the end of each day.

How long will it take to install my air source heat pump?

We aim to install air source heat pumps within five days: three days for the removal and mechanical installation, one day for the wire up and one day for the commissioning.

However, it could take longer if you are having other measures - such as solar PV panels, ventilation, door undercuts, LED lighting or loft Insulation - installed at the same time.

What are the likely disruptions during the air source heat pump installation process?

  • Heating and hot water will be turned off for the early part of the installation (two days)
  • Electrics may be turned off for part of a day during the wire up process
  • Carpets may need lifting if the pipework is to run under the floorboards
  • Belongings may require moving so the installation team can access areas which require pipe runs and radiators. Contractors are happy to help move heavy objects, but please move any valuable belongings before they arrive. The surveyor will outline this with you before the installation.