Recent negative news reports about exhaust air systems are probably the result of incorrect installation, application and sizing, not pump performance, says Plumbing Trade Supplies (PTS).
Homeowners across the UK, in particular a number of housing association tenants, have claimed they faced soaring energy costs due to the inadequacy of the exhaust air systems.
However, product director of renewable energy products at PTS, Ian Stares said that the systems themselves are unlikely to be to blame.
“PTS has been warning for some time that the key to achieving the best possible performance from heat pumps is correct application, installation and sizing,” he said.
“I have great sympathy for the households affected, but I suspect that the properties have inadequate insulation or the heat pumps have been improperly sized, which would lead directly to these sorts of problems. We must also be aware that there are hundreds of heat pumps installed in the UK which are achieving and delivering cost effective heating performance.”
Stares said that many in the heating industry have known for some time that a well-designed heat pump installation, correctly sized and installed properly has the capability to offer significant energy cost and carbon savings, but there is the potential for problems if pumps are incorrectly installed and/or sized.
He said that there are a number of factors that need to be taken into account before a heat pump is installed. For example, the house requires good insulation as heat pumps work with a constant low heat that must be able to build up over time, in order that a sufficient temperature is felt around the whole house.
He added: “A common mistake is specifying the wrong size heat pump or radiator which will dramatically affect the heat output. Either there has been an inaccurate heat loss calculation or no heat loss calculation has been carried out.
“The standard CoP (Coefficient of Performance) measurement of a heat pump is usually made at seven degrees air temperature and 35 degrees water temperature. However, more informed installers will be using minus three degrees air temperature which takes winter conditions into account whilst completing an accurate heat loss calculation for the home.”
Stares pointed out that the value of heat pumps is being proven on the Continent. “Heat pumps are still in their infancy in the UK and installation best practices have yet to catch up with our European counterparts,” he explained. “It is noticeable that in Germany, where installation practices are much more advanced, the CoP regularly reaches much higher levels than we commonly achieve in the UK at present.”
Stares also believes that installers play a vital role in ensuring that these problems do not continue in the future.
“It is the responsibility of the installer, manufacturer and the merchant to make sure a renewable energy product is going to be as efficient as possible,” he said.
“Thus training is important with the Microgeneration Accredited Scheme being an essential component of the installer tool kit as well as attending manufacturer’s courses, which can help to ensure that sizing and installation is done correctly. In addition informed merchants are now collaborating with training organisations to providing training course on all aspects of renewable energy technologies.”