Ground source heat pumps explained Ground source heat pumps - trial results
Just 13% of heat pumps monitored in an Energy Saving Trust (EST) trial were deemed to be working well.
The EST monitored 83 different heat pumps (54 ground source heat pumps and 29 air source heat pumps) in UK properties over a 12-month period from 2008 to 2009, to identify which factors affect how well a heat pump works and to better understand how households are actually using heat pump technology.
Heat pump trial – key findings
The study found that only 13% of all sites in the trial achieved a level of efficiency the EST considers to be a 'well-performing' system, with the rest scoring below this benchmark. Ground source heat pumps were found to be slightly more efficient than air source heat pumps.
The report concluded that the worst-performing sites illustrate how customers need to be completely sure they're investing in the best system for their property and lifestyle.
Many systems appeared to be installed incorrectly, and control systems were generally complicated. The trial came to the following conclusions:
- Design and installation. There was a big variation in performance, with several early heat pumps incorrectly designed or installed.
- Simplicity. The best heat pumps tended to be the simplest in design and scope.
- Hot water. It's unclear whether using a ground source heat pump to also produce hot water impacts overall efficiency.
- Heating controls. The EST described an overall 'failure to explain proper control requirements' to heat pump customers, with many unsure how to properly use the controls to work their system.
- After-care – The installation company should be required to provide quality after-sales services.
What to expect from a heat pump-powered system
- Your home may take longer to heat up.
- If you're using radiators, expect them to feel warm rather than hot – heat pumps produce ower temperatures than a boiler.
- You'll probably need to have your heat pump on for more hours a day than you would with a boiler.
- You might need a separate electric heater to help provide all your heating and hot water needs.
- The heating controls that come with a heat pump can be complicated – insist on easy-to-use controls and a demo from the installer.
- Check the credentials of the ground source heat pump installer you're using – they should be accredited by the Microgeneration Certification Scheme, be able to design a system specifically suited to your property and offer an after-care service.