Heat recovery ventilation units – how do they work?

A heat recovery ventilation unit provides a clean, fresh environment in your home. It delivers fresh filtered air from outside the building to the living areas and bedrooms and extracts stale air from high moisture areas such as bathrooms, kitchens and laundries. At the same time, the heat recovery ventilation unit recovers up to 96% of the heat from the exhaust air and transfers it to the incoming air. With a heat recovery ventilation unit, you can maintain a high air quality without excessive additional energy costs.

Integrated humidity sensors constantly monitor the relative humidity in the rooms and the air volume supplied to the house is automatically adjusted until an adequate air quality is obtained. A Dantherm heat recovery ventilation unit will provide continual clean air with a minimal heat loss.

What type of exchanger suits me best?

There are different ways of recovering heat from the air. Three of the best known methods are using rotary heat exchangers, cross flow heat exchangers and counter flow heat exchangers.

The counter-flow heat exchanger is the most energy-efficient type, and has the added advantage of not leading odours around the building. A counter-flow heat exchanger acts by allowing the hot extract air to pass the cooler supply air in the heat exchanger, ensuring that the heat is transferred between the two airstreams without the supply air and extract air mixing.

Enthalpy counter flow heat exchanger stand out

The enthalpy heat exchanger is the latest in a variety of different exchanger types in Dantherm's range, and the new technology delivers numerous benefits: Both sensible energy (heat) and latent energy (humidity) is recovered from the extract air and transferred to the fresh supply air. In winter, the humidity from the extract air is transferred to the fresh supply air, thereby recovering the energy from the humidity in the extract air and avoiding unnecessary drying out of the home. In summer, when the outdoor air has a relatively high humidity, the supply air is dehumidified through the enthalpy heat exchanger so that the supply air feels cooling.

The enthalpy heat exchanger consists of a polymer membrane that transfers heat and humidity. As the membrane is air- and watertight, this ensures that odours, bacteria, viruses etc. are not transferred from the extract air to the supply air. The enthalpy heat exchanger can function down to -5 degrees Celcius without any preheating. This ensures balanced ventilation for the main part of the year without preheating, which reduces heating and electricity bills for residents. Overall, the rewards gained from an enthalpy heat exchanger are a lower heat bill and a better indoor climate.

The benefit is increased comfort and substantial energy savings!

The heat exchange takes place in the counterflow heat exchanger. It consists of two separate, isolated air flows. One air flow is connected to the outdoor air and the other is connected to the extract air – in a way that the air flows are never mixed. Up to 96% of the heat from the extract air will be recovered and transferred to the incoming outdoor air, thus reducing energy bills, and making it a worthwhile investment.

A Dantherm heat recovery ventilation unit can change all the air in your home in a matter of approximately three hours.

For more information, please download Dantherm’s full Selection Guide for residential ventilation.