Domestic Heat Recovery and Ventilation Systems
All buildings require ventilation throughout the year, both for the health of their inhabitants and for the integrity of the buildings themselves. Most households are currently ventilated by opening doors and windows. However, this is highly inefficient due to heat loss, and also potentially a security risk.
Most domestic and small scale heat recovery systems come in the form of a mechanical ventilation heat recovery system (MVHR). These function in the way outlined here (that is, by transferring the heat contained in the outgoing air to the cold, fresh air coming in), and can usefully provide both heating and ventilation.
Typically the warm, stale air is extracted through ducts from the rooms which produce the most heat (i.e. bathrooms, kitchens and utility rooms), and heat from this air is used in rooms where the heat is needed, such as lounges and bedrooms. One should remember that it is not the air from bathrooms and kitchens that is piped into the sitting room and bedrooms, but the heat contained in the air. This means that with this type of system there is no danger of undesirable smells being piped into other rooms.
Domestic MVHR systems are becoming increasingly popular as the air insulation standards of buildings are improving. As houses become more airtight, the need for efficient ventilation is becoming greater. By providing constant ventilation, MVHR systems improve the air quality inside the building, which can present significant health benefits.
Sufferers of asthma, for example, may benefit from the installation of an MVHR system, as the overall humidity and condensation in the building are reduced. This also has the effect of reducing a building’s susceptibility to damp, which is beneficial for both the building and its inhabitants.
It is also common to install pollen filters in MVHR systems, which can greatly reduce the suffering of those afflicted with hay fever and other allergies. In the summer months, when less space heating is required, it is possible to disable the heat exchanger in the system and just use it for the purposes of ventilation.
MVHR domestic systems are fitted with a control panel which regulates the rate of heating ventilation. For example, it is possible to increase ventilation when there are more people in the house or when you are cooking, and decrease it if the house is temporarily uninhabited.
MVHR systems are often coupled with ground source heat pumps.