
21st-22nd February 2026 - time to get your dream home started!
GET TWO FREE TICKETS HEREThe PKOM 4A is an energy efficient compact service unit providing whole house ventilation with heat recovery, space heating and cooling, together with enough domestic hot water for a family of four.
This compact service unit provides heat recovery ventilation, with an integral heat pump for warm air to be introduced to your habitable rooms, via the ventilation ductwork. The heat pump can be reversed to provide cooling as well, great for those warmer summer nights when you could sleep better with a 4-5°C temperature reduction. There is a second heat pump within the PKOM 4A unit to provide domestic hot water in a 212L/ 220L tank underneath, making it the only compact service unit of its kind. This heating and ventilating system can be up to 680% efficient in comparison to a gas boiler at only 90% efficiency.
This is all in a footprint of less than 0.75m² – convenient if you have limited space in your home or your heat demand is low enough to not warrant a formal heating system. The PKOM 4A uses the next generation R-1234yf refrigerant making the system more environmentally friendly, with an incredibly low global warming potential of less than 1 and an atmospheric lifetime reduced from around 14 years to just 11 days! The PKOM 4A won Best Renewable Heating Solution in the 2018 Build It Awards and is a PassivHaus Certified component and therefore particularly well suited to homes that are to be built to Passivhaus standard, or a very well insulated and airtight with low U-values.
In Britain, homes of between about 50m² and 140m² (at a 2.4m ceiling height) would be suitable for the PKOM 4A, so apartments and townhouses are ideal candidates. Total Home Environment can complete a room-by-room heat loss calculation to establish if this system will be suitable for you and your home.