The Energy Savings Trust has caused quite a stir. Following the publication of a look into nearly 100 Ground Source and Air Source Heat Pump installations across the UK, the initial results are less than impressive. The EST’s summary on the report are as follows:
You should consider a heat pump if you live in a:
• Well-insulated existing property that cannot access the gas network. Heat pumps have the potential to reduce running costs compared with oil, direct electric, LPG, or coal, and can provide substantial carbon savings over the lifetime of the installation.
• New-build property.
How to get the best performance from a heat pump
• Ensure your dwelling is insulated as much as possible (e.g. cavity and loft insulation) prior to a heat pump being installed
• Install the heat pump with low temperature under-floor heating or properly sized radiators
• Insist upon understandable, user-friendly controls.
What to expect from a heat pump
• Since heat pumps provide a lower temperature heating compared with boilers, radiators will be warm rather than hot
• A house with radiators may heat up more slowly
• The heat pump will run for longer hours than a conventional boiler but if properly controlled will switch on and off with the heating requirements of the house
• A properly sized and installed heat pump should be able to provide all of a household’s domestic hot water, but many systems are installed with a supplemental electric immersion heater.
What was not mentioned in the summary, and yet has been the main talking point of the research, was that of all the systems tested, the peak COP achieved was only 3.2, with both Ground Source and Air Source averaging a COP of 2.2. This is a far cry from the manufacturer’s claims in the product literature, which frequently claims between 5 and 7. The report itself recognises that none of the results achieved were as successful as similar tests held in Europe.
So why have the UK’s Heat Pumps failed and is this all bad news for the UK’s renewable targets?
The primary causes for the poor performance are three fold; cheap or unsuitable equipment, incorrectly installed systems and the differences in the British climate. This is then often compounded by complicated controls that the user cannot effectively manage. Overall, it paints a relatively grim picture of the level of expertise and understanding of the technology in the UK. Although it does not bode well, there is a positive aspect to the findings for Justin Broadbent, MD of isoenergy who have been designing and installing heat pump systems since 2005, “I think people’s confidence in Heat Pump’s has been damaged, but it does finally prove what we have been trying to say at isoenergy for years – you simply can’t get away with throwing in any old cheap bit of kit and expecting it to work.”
Isoenergy has been extolling the virtues of higher quality, more efficient and longer lasting systems. The systems are installed by an in house team of highly qualified engineers and are then supported with a thorough post-installation service policy. These have been core principles at the company, but are evidently being lost along the way by other installers. It is for that reason, and hopefully to prove the true potential of Heat Pumps, that isoenergy are hoping to be part of the EST’s next stage of research.
It may be an uncertain time for Heat Pumps, but if this wobble will result in only the best installers being trusted with an important part of the UK’s micro generation future, it will be well worth it in the long run, both environmentally and financially for the system’s owners.