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House dust mite allergy
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Heat Exchangers
Ventilate & Conserve Energy
to fight allergy to mites or fungi



Domestic heat exchangers are promoted for mite control by:

Baxi Clean Air
PO Box 192

Customer Freephone: 0800 731 2969
Telephone: 01274 697800
International Telephone: +44 1274 697800
Fax: 01274 697801

Website: http://www.baxicleanairsystems.co.uk/

  A range of models is available. The smallest can be inserted rather like an electically powered airbrick to serve a single small bedroom and the largest is fitted in the roofspace with ducting to rooms throughout the house.

Each unit contains two fans. One draws in fresh outside air, and the other expels stale indoor air.

The two airstreams pass through a cassette in which they are kept separate by a thin plastic film. Because the air layers are thin and because of the thinness of the plastic, heat moves efficiently from the warm air to the cold air.

Noise levels from the fans are low enough not to be obtrusive in a quiet bedroom. The manufacturer claims that the high quality of the fan motors means that they will function continuously for years without undue deterioration in noise levels.

Advantages over dehumidifiers are:

  • Much lower power consumption; much lower running costs.
    In summer, heat production by dehumidifiers can be a problem. With heat exchange ventilators it is not. My dehumidifier consumes 350 watts. A comparable heat exchange ventilator might consume 35 watts.

  • Much lower noise levels

  • People have a tendency to switch dehumidifiers off. Heat exchange ventilators are acceptable for continuous use.

  • No need to empty water container.
    This includes ability to continue working when the home is empty e.g. during holidays. Unlike dehumidifiers with a drain to the outside, heat exchangers are not affected by frost.

  • Replace indoor air with outdoor air instead of recirculating indoor air and dust.

  • No freestanding item taking up space in room.

A criticism of the idea is:

  • In summer outdoor humidities may be high and outdoor temperatures not particularly different from indoor temperatures. So for a large part of the year the system would not reduce humidity to low levels, though it should still help to get rid of excess water vapour generated indoors. The question is then whether the effect in winter is big enough to produce an effect on mite populations which benefits health. We are awaiting information from the manufacturer and other sources to answer this question. Meanwhile it is possible that this is a fatal flaw of the system in a climate like that of the UK.



Click here to return to page about house dust mite control.

If you spot mistakes or have questions, please e-mail me .
This page is maintained by Martin Stern
It was updated on 9 April 1998. 5 Apr 2003 (link to Baxi: thanks to James P.).

Copyright © 1997 Asthma and Allergy Information and Research