Image credit: EcoHouseAgent
Back in 2008 Lloyd stirred up controversy with his post blowing hot and cold on ground source heat pumps, and his stance was later validated when Green Building Adviser concluded that groundsource heat pumps were not as efficient as claimed, and way too expensive to be a sensible response to climate change. Now a study over in the UK seems to suggest that installation of both ground- and air-source heat pumps leaves an awful lot to be desired—in fact fully 87% of heat pumps studied did not perform as well as they should. A report over at The Guardian on the under-performance of UK heat pumps brings news of a new study from the Energy Saving Trust which tracked the performance of 83 newly installed heat pump units over a 12 month period. The results were astounding—astoundingly bad that is.
87% failed to reach a system efficiency of 3, which is the level the Trust defines for a "well-performing" system. 80% failed to meet 2.6, which is the level that the EU Renewable Energy Directive is considering for classification as a renewable source of energy.
Crucially, the Trust is not at this stage claiming that heat pumps are not an effective solution for heating and cooling, but rather that the industry needs to step up its game when it comes to installation, as Adam Vaughan of The Guardian explains:
"The Trust blamed the use of multiple contractors for fitting systems instead of a single contractor as used in Europe, wrongly sized systems, complicated controls and a lack of education for householders using them. However, the Trust said that for many of the 5 million people in the UK living off the gas grid and currently using energy sources such as oil to heat their homes, the heat pumps could offer carbon and energy bill savings."
Nevertheless, Lloyd will no doubt be feeling more than a little validated by this study. While the relatively modest expense of an air-source heat pump may make it a good investment in many situations, the huge capital investment needed for ground source systems is a hard sell at the best of times. If installation errors can cause systems to perform so poorly, it's just one more reason to consider spending your money on reducing demand first.
More on Ground- and Air-Source Heat Pumps
Blowing Hot and Cold on Ground Source Heat Pumps
Are Ground Source Heat Pumps a Good Choice?
Eco-Cute Heat Pump Uses CO2 as Refrigerant
Jargon Watch: Geothermal vs Ground Source Heat Pump
Forums: Why Does TH Prefer Gas to Heat Pumps But Also Opposes Frac?