Air source heat pumps, designed around your home.

Scroll the picture sideways to see all of it. Every label is written out below.

1. 

   A house, and one machine outside it

   The house is drawn straight on so nothing is hidden. The heat pump is the box standing outside on its own small base - there is no machine indoors at all.

2. 

   

   The warmth is already in the air

   Ordinary garden air is drawn in at the finned coil on the side of the machine, gives up a few degrees of its warmth, and is blown straight back out again a little cooler. Even cold air has warmth in it worth collecting.

   • Outdoor air is drawn in here
   • The same air is blown out here, a few degrees cooler
   • Finned coil - the air gives up its warmth here
   • Electricity meter
3. 

   

   Only water crosses the wall

   Two insulated pipes go through the wall and that is the whole of the connection: warm water out to the house, cooler water back to the machine. The air stays outside, always.

   • Insulated pipes through the wall
4. 

   

   A plant room with no heat pump in it

   This is the whole of what an air-source system puts indoors: a hot-water cylinder, the manifold for the floor, and the electrics. The machine itself never comes inside.

   • Fuse board
   • Hot-water cylinder
   • Heating coil - heating water never mixes with your tap water
   • Underfloor manifold
   • Cold water mains
5. 

   

   Inside the machine: four steps, over and over

   This is the only part of the whole picture that uses electricity. A sealed refrigerant goes round and round, and at each of the four stations it visibly changes.

   • Electricity from the grid
   1. 1 CollectevaporatorEnvironmental energy warms the refrigerant until it boils. It leaves as a warm gas at low pressure.
   2. 2 SqueezecompressorElectricity drives the compressor, squeezing that gas into a much smaller space. It leaves hot and at high pressure.
   3. 3 ReleasecondenserThe hot gas hands its heat to your heating water and condenses. It leaves as a hot liquid, still at high pressure.
   4. 4 Resetexpansion valveA valve drops the pressure and the liquid flashes cold. It leaves as a cold mist, ready to collect more.
6. 

   

   Where the heat actually goes

   Warm water runs to the pipes buried in the ground-floor screed, up to the radiator, and through a sealed coil inside the hot-water cylinder. Your tap water never touches it.

   • Underfloor heating in the screed
   • Radiator
   • Warm water out
   • Cooler water back
   • Your shower and taps

7. Three separate circuits. Heat passes between them; nothing is shared.

   Outdoor air heat crosses here Refrigerant heat crosses here Heating water

   The outdoor air stops at the machine. The refrigerant is sealed inside it. Only warm water goes through the wall into the house.