Hybrid Installation, Bedfordshire
The 6kW Grant Air Source Heat Pump System and pre-plumbed, 180-litre cylinder was installed in April 2013 and is working as a hybrid heating system with a gas boiler and a wood burning stove, to provide all the heating and hot water the family needs.
The timber-framed, brick-clad house was built in 2006 and with a young baby in the home the family has a high hot water demand. “It’s important for us that we have hot water whenever we want it and also keep our son’s bedroom at a pre-set level of 20°C,” explains Alice Knight the homeowner.
The system has been set up so that the Grant Air Source Heat Pump System wireless thermostat in the baby’s bedroom becomes the ‘master’ unit during the night ensuring that the temperature is constant. The hot water is also set to automatically replenish whenever the cylinder temperature drops below 43°C, which suits the family’s lifestyle as it ensures that there is always hot water on demand. Despite this hot water requirement, the system has returned a COP (Coefficient of Performance) of 3.0.
The family has also programmed the individual prices of gas and electricity into the Grant Air Source Heat Pump System’s control system so that it can decide when it is best to run the heat pump or the gas boiler to maintain comfort levels in the most cost efficient way possible. This way, the family knows that the gas boiler will only come on when it demonstrates that it is the most economical means of heating the home.
The Knight family is also expecting to benefit from around £500 a year in payments from the Renewable Heat Incentive. The home has a floor space of 105m2 and is divided into two ‘electronic’ heating zones with priority switching between upstairs and downstairs based on which areas of the house are being occupied during different times of the day. Due to the hybrid configuration most of the original radiators could be retained.
The house has an EPC (Energy Performance Certificate) rating of ‘C’ for energy efficiency, with heat losses calculated at 4.3kW at -3°C outdoor temperature and 21°C indoor.
“We have been delighted with the heating and especially the constant temperature it provides,” says Alice.“The system has also quickly adapted to suit our lifestyle and controls both the heat pump and the gas boiler, so we really don’t need to worry about anything.”