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Heat Recovery

A vortice domestic heat recovery unit with input and exhaust ducts

MVHR Heat Recovery Units – Energy Efficient Ventilation

To meet new standards, MVHR (Mechanical Ventilation with Heat Recovery) systems are being fitted in new or existing homes. At Energy BY DESIGN Dorset, we can create the perfect air flow solution for you.

Why the need for Heat Recovery Units?

With the improvement in insulation standards and the move towards producing air tight properties, the problem of air quality has become an issue. This is where heat recovery solutions are at their most efficient.

In the past, Building Regulations required extract fans in areas such as bathrooms and kitchens to remove warm moist air and prevent condensation. The improvement in weather seals around doors and windows prevented fresh air from entering the building. With the need for extractor fans the Building Regulations then introduced trickle vents to provide the necessary air changes.

Although this reduced condensation, the continuous air changes within the building also removed a large proportion of the heat.

Heat recovery units are the solution to new and existing homes to overcome these problems.

Heat Recovery Systems – How Do They Work?

Diagram of Air Recycling Process Carried Out By Heat Recovery System

Lofts and utilities are often used to site the heat recovery unit, although plant rooms are ideal.

Recycling Warm Air

Warm moist air is extracted from wet areas of a building (e.g. utility, kitchen, bathrooms and shower rooms). This air passes into the unit across a heat exchanger where up to 92% of the heat is extracted. The heat is then transferred to fresh air being drawn in from the outside. Warm dry air is then returned to the living areas of the building.

Cost Effective, Low Maintenance Heating

It may seem that the amount of energy required to run the fan for the heat recovery unit would prove to be expensive, but the introduction of DC fan motors can reduce the energy requirements to a minimum. This computes to running the unit for 200 hours at a cost of only around 11 pence. The amount of heat retained by the unit far outweighs this cost – this can be further mitigated if the property is fitted with solar PV panels (which produce their own electricity).

The MVHR system is automatically operated using temperature and humidity sensors within the unit to control the air flow settings. The units require minimum maintenance, with most filter’s being changed once a year. The DC motors as well as being very economical are also very quiet in operation.

MVHR – A Tailored Air Flow System

The overall effect of an MVHR system is to increase the comfort levels within the property, removing moist stale air and replacing it with pre-warmed fresh air. Condensation mould is eliminated and the saving on heating costs is significant. As the incoming air is filtered, pollen and other particles are also removed which can help with any allergies.

Heat recovery systems come in various sizes and capacities depending on house type and the number of air movements required.

To find out more on heat recovery, please contact our team at energy BY DESIGN.


Our supply, survey and installation service covers the following areas: Bournemouth, Christchurch, Dorchester, Poole, Romsey, Salisbury, Southampton, Wimborne and Winchester and other areas in Dorset in Hampshire. Site surveys outside a 30 mile radius of Wimborne will incure a charge a £25 which is deductable should you accept our quotation. We are also pleased to invite enquiries from further afield.