By guest columnist Bill Wright, head of energy solutions, Electrical Contractors’ Association
DECC’s initial guide to the Domestic RHI will give a big boost to the renewables industry when it comes into being next spring. Air to water and ground source heat pumps will become very viable alternatives for those domestic properties that are off the gas grid or relying on oil fired boilers.
Heat pumps are increasingly ‘black box ‘installations which require electrical work to install, which requires competent electricians. They require a substantial power supply, so checks should be made that there is sufficient supply capacity installed to accommodate the additional power, and a significant amount of control wiring. If there is already a plumbed in suitable heating system then the water connections can be relatively simple, but should be carried out by a competent person. Remember the water temperature output from most heat pumps is lower than that of a gas boiler and the heating system, radiators or better still under floor heating, should take account of this. An additional heating source will be required to boost the hot water supplied up to the required temperature, around 60C in the hot water tank.
If the heat pump is the only source then a ‘deemed’ calculation is used for RHI payments. The ‘deemed’ value is calculated using the efficiency, or ‘Seasonal Performance Factor’ of the pump and the calculated energy use of the house from its EPC rating after the installation.
There may be a metering installation required if another heat source is connected to the system or DECC request one to be fitted for monitoring purposes. DECC are also offering a bonus payment to those households installing meters voluntarily for the first 2500 applicants in the first year.