QUICK GUIDE HYBRID HEAT PUMPS
One of the big drivers for taking on a major home building project is to achieve a lowenergy, low-bills household. A key piece of that puzzle is how you choose to provide central heating and hot water. A popular option for those creating a new home is to install a heat pump, but is it the right choice for you?
Because ASHPs do not perform quite so effectively when the air temperature is very low (in the coldest parts of winter when you really want the heating on), there is growing interest in hybrid heat pumps. These include a fossil fuel boiler (mains gas, LPG or oil) that takes over when the air temperature drops.
What is a heat pump?
A hybrid system uses intelligent technology to automatically select which mode is the most efficient and affordale to use. So, the ASHP component would likely be used mostly during the shoulder months of the heating season – ie at either end of winter – to deliver efficient, cost-effective warmth. This approach can make a lot of sense for renovators who don’t want to go to the disruption of updating the rest of their central heating, but may not be the best approach for self builders due to the extra cost of installing multiple technologies.
Heat pumps take heat from low-grade sources and concentrate it for use in space heating and hot water systems. The most common sources of the warmth they require to work effectively are the air (air source heat pumps) and the ground (ground source heat pumps). Energy can also be extracted from water – hence water source heat pumps. Fundamentally, they all work on the same principle as a refrigerator, but in reverse.
It takes electricity to run a heat pump, so while it does make use of renewable energy and should be lower carbon than a fossil fuel boiler, it’s not a completely carbon free system. For each unit of power used by the appliances, you get more than one unit of heat output – and this is what makes them an attractive option.