Exhaust air / heat recovery

An Exhaust Air Heat Pump (EAHP) extracts heat from the exhaust air of a building and transfers the heat to the supply air, hot tap water and/or hydronic heating system (underfloor heating, radiators). This requires at least mechanical exhaust, mechanical supply is optional, see mechanical ventilation. This type of heat pump requires a certain air exchange rate to maintain its output power. Since the inside air is approximately 20-22 degrees Celsius all year round, the maximum output power of the heat pump is not varying with the seasons and outdoor temperature.

Why throw out old energy when you can recycle it instead?

an exhaust air heat pump is basically an energy recycling system. It collects energy from the warm inside air as it leaves your home via the ventilation system, and re-uses it to heat up fresh incoming air and tap water.

If you’re building a new house or developing new apartments, now’s the perfect time to take advantage of the energy efficient heating technology. Install an exhaust air heat pump and you can enjoy a healthy, oxygen-rich atmosphere inside your home, at the same time as reducing your electricity consumption by more than 50%.

When to choose an exhaust air heat pump?


New build or replacement?


For an exhaust air heat pump to work, the necessary ventilation system has to be constructed at the same time as the house itself. It is neither cost-effective nor practical to install an exhaust air sys- tem after the house has been built. this means there are two very specific situations in which you should choose an exhaust air heat pump:

1. When building a new house or developing
new apartments
Choose an exhaust air heat pump at the planning stage and the necessary ventilation ducts will be included in your home’s design. When your house is ready and the exhaust air heat pump is installed, you can start to enjoy the most efficient indoor heat recycling on the market. Fresh warm air will flow into your home, hot water will run from your taps and your energy bills will be a fraction of the usual amount!

When building a new house or developing new apartments, there are numerous heating systems and different combinations of energy sources to choose from. the one you select will obviously depend on the size of the house and the household’s energy demands, as well as the extent of your ‘green ambitions’. however, as a rule of thumb, an exhaust air heat pump is the most cost-efficient solution for small to medium sized homes.

2. When it’s time to replace an old exhaust air heat pump

If your home was originally constructed to accommodate an exhaust air heat pump, and the original pump is reaching the end of its service life, this is the perfect time to switch to one of the new generation of heat pumps, and make your heating system more energy efficient than ever.

How do exhaust heat pumps work?

an exhaust air heat pump extracts air via ventilation ducts positioned in the wet rooms of the house such as bathrooms, kitchens* and utility rooms. Ventilation can take place in two different ways: by exhaust air only or by a combination of exhaust air and heated in- take air.

In the former, the air in the house is conveyed from rooms with out- door air diffusers to rooms with exhaust air diffusers. the latter is designed for houses with heating systems where some of the heat supply is provided by a heated supply air. the air in the house is conveyed from rooms with supply air diffusers to rooms with exhaust air diffusers.

On its way out of the house, heat is extracted from the old air and transferred into the heat pump’s refrigerant circuit. the cooled air is

then discharged. Meanwhile, the vapour compression cycle of the heat pump raises the temperature of the refrigerant and transfers the extracted heat into a water-based system that can either warm the domestic hot water or heat the building, or both.

an exhaust air heat pump can cover the heating requirements of a well-insulated house in all but the coldest conditions. When working efficiently, it can reduce your home’s energy consumption for heating by up to 50% when compared to conventional heating systems.

the exhaust air heat pump also works well in conjunction with an underfloor heating system to give you a comfortable indoor temperature, low running costs, a long service life and minimal maintenance

Here are two good reasons

Cut your electricity bills dramatically

Frankly, who wouldn’t want to do that? Instead of letting the energy you’ve already paid for escape via the ventilation ducts along with the used inside air, it makes perfect sense to recapture that energy and use it again.

Depending on the model you choose and the size of your home, savings achieved from installing an exhaust air heat pump can be as high as 50%. so you only pay half or even less of the cost of heating and hot water compared with a conventional electric boiler with mechanical exhaust air ventilation. the rest is free.

Reduce environmental impact

By merely extracting existing energy from your home and reusing it to heat up the tap water and the radiators, an exhaust air heat pump leads to much lower CO2 emissions. What’s more, an exhaust air heat pump can be connected with a solar energy system such as solar panels on the roof of your home. this means you can take advantage of completely free energy from the sun whenever it’s available, without being fully dependent upon it.