How does Heat Recovery Ventilation work?

There are two different types of heat recovery system, Whole House Mechanical Ventilation with Heat Recovery (MVHR) and Single Room Heat Recovery (SRHR).

Whole House Heat Recovery is a centralised system, normally located in the loft space of a house. It works using the principles of both supply and extract ventilation. Warm and moisture-laden air is extracted from the bathroom, kitchen, WC and utility room of a property which is drawn into the main system and passes over a heat exchange coil before being ducted outside to atmosphere.

At the same time, fresh air is drawn from outside into the system, collecting up to 90% of the heat from the extracted air as it passes over the heat exchange cell. This fresh, filtered and tempered air is then supplied into the living room areas of the home, the bedrooms, living and dining areas.

Why have a Mechanical Ventilation Heat Recovery system?

Modern homes are usually built to far higher technical standards than buildings constructed a few decades ago and are much more energy efficient, largely thanks to better heat insulation. One key area of improvement has been to make buildings more airtight so they hold onto the heat we put into them for longer. But there’s a drawback: our homes need regular changes of air to keep them healthy. Baths and showers, doing the dishes, clothes washing machines, drying clothes indoors, and even simple breathing produce astonishing amounts of water inside our homes: according to research a typical family will produce 10–15 liters of moisture each day! Let that problem go unchecked and you’ll get problems like mold and mildew, dust mites and a greater risk of asthma. Opening doors and windows is the obvious way to get rid of moisture and bring in fresh air, but if you do that in winter you might just as well flush your money down the toilet: all the heat you’ve expensively introduced into your home will blow away in the breeze. An old drafty house solves this problem by being automatically well ventilated, but it’s probably also freezing cold because it’s useless at holding onto heat; a modern energy-efficient home solves the draft problem but may be stuffy and underventilated.

Please call to discuss installing a MVHR system in your home