What is MVHR and how does it work?

A mechanical ventilation heat recovery (MVHR) system provides pre-warmed filtered fresh air into most rooms 24 hours a day. These systems extract moist air and smells from bathrooms, wet rooms and kitchens and recover the heat from the extracted air via a heat exchanger, resulting in minimal heat loss and pre-warming the fresh incoming air. The system constantly extracts moisture, maintaining internal humidity levels at a healthy level of between 45–55% by carefully balancing the system. A well-designed and installed system will be quiet and, as a result of not having trickle vents, you will not hear noises outside. The filters catch pollen and other allergens to help allergy sufferers. Most systems automatically sense humidity and will boost when someone is cooking or showering. One of the many benefits is that the system can bypass heat recovery in the summer months and purge-ventilate at night to cool the building, meaning you don’t have to open windows.