Air source heat pumps
The standard choice for most homes in Tunbridge Wells. An outdoor unit takes heat from the air and feeds your radiators, underfloor heating and hot water.
Air sourceHow an air source heat pump works
An air source heat pump is a refrigeration cycle running backwards. It absorbs low-grade heat from the outside air, compresses the refrigerant to raise its temperature, then transfers that heat into your central heating water. Because it moves heat rather than creating it, it delivers roughly three to four units of heat for every unit of electricity it uses. A gas boiler, at best, gives you slightly under one.
It keeps working in cold weather. Output drops as the outside temperature falls, which is why correct sizing against your worst-case design day matters, but a properly specified unit will heat a house through a Kent winter without a backup boiler.
Flow temperature is what decides your bill
This is the part most quotes gloss over. A boiler runs at 70 to 80°C. A heat pump is most efficient at 35 to 45°C. The lower the flow temperature it can run at while still heating the house, the cheaper it is to run.
Getting there usually means upsizing some radiators, because a radiator emits far less heat at 45°C than at 75°C. In a typical Tunbridge Wells three-bed we might change four to six radiators and leave the rest. An installer who tells you no radiators need changing has either done a very careful calculation or none at all, and it is worth asking which.
What the installation involves
- Room-by-room heat loss survey. Every room measured, fabric assessed, and the design flow temperature set. Not a floor-area estimate.
- Outdoor unit siting. Position, base, clearances and the MCS 020(a) noise assessment for permitted development.
- Cylinder. Heat pumps need a hot water cylinder, so if you are on a combi we need to find space, typically an airing cupboard or loft.
- Pipework and emitters. Flow and return runs, plus any radiator changes the design calls for.
- Electrical supply. A dedicated circuit, and occasionally a DNO notification for larger units.
- Commissioning and handover. Weather compensation set properly, and time spent showing you how to run it, which is where a lot of disappointing systems actually go wrong.
Timescales
Most domestic installations take three to five working days on site. A straightforward swap on a modern house with adequate radiators can be done in two. Larger period properties with significant pipework and emitter changes can run to a week or more. From first survey to commissioning, allow four to eight weeks including the grant process.
Brands
We install Daikin, Mitsubishi Electric, Vaillant, Samsung, NIBE, Grant and Worcester Bosch, and recommend on the basis of your design flow temperature, the noise position and the space available rather than on which manufacturer offers the best installer margin.