Ventilation Systems

3   Dehumidifiers
 

A domestic dehumidifier is a variation of a common refrigerator.  A fan recirculates warm moist room air over chilled metal plates inside the dehumidifier.  Humidity condenses on the plates, in exactly the same way that humidity condenses on the outside of a drink can or glass.  Condensation dribbles from the chilled plates into a bucket and you feel good when you empty the full bucket of water.  Here's what you may not know....

A dehumidifier removes moisture by recirculating room air.  If the air is stale, odorous and polluted, the dehumidifier will remove the moisture, but nothing else.  In fact if the room is occupied while the dehumidifier is in operation, indoor contaminants increase.  Recirculating foul air "stirs up" pollutants such as dust mite allergens.

Claims that dehumidifiers control dust mites in normal home use are incorrect.  In an average New Zealand home one dehumidifier makes little difference to dust mite populations.  NZ Standard 4303 "Ventilation for Acceptable Indoor Air Quality" recommends whole home ventilation (with fresh outdoor air) at the rate of one air change every 3 hours.   A recirculating air dehumidifier does nothing to ventilation needs.  Many dehumidifiers are noisy, and scientific tests have identified that unless appropriately disinfected, the inaccessible cooling plates, water buckets and surrounds of dehumidifiers support and encourage the growth of harmful moulds, fungi and bacteria.  Click here to visit the web site of an independent building inspector and see what he has to say on the subject of dehumidifiers.

4  Heat Recovery Ventilator (HRV)
 

HEAT RECOVERY VENTILATOR (H.R.V.)
Ventilates, Dehumidifies & Recycles Waste Heat
(with doors & windows securely shut)

The HRV illustrated above is shown installed in the roofspace, (sourcing OUTDOOR AIR). Many homes where ventilation is to be retrofitted, have space problems – between two story floors, flat roofs, etc, presenting what appear to be insoluble problems with regard to installing an HRV.  CLEANAIRE has a range of over 22 models of HRVs to suit every home.

We have models for …..walls, outdoors, rooftop, underfloor, basement, etc -- whatever the problem we are almost certain to have a solution.

CLEANAIRE HRVs are designed to ventilate homes with 100% fresh outdoor air, at the rate recommended in NZ Standard 4303 "Ventilation for Acceptable Indoor Air Quality" ie one air change every 3 hours.   Each model has two ultra-quiet fans, one to exhaust stale humid air and another supply fan to replace exhausted air with dry warm outdoor air.  Heat from the exhaust air stream is "captured" by a heat exchanger and recycled to preheat the incoming cold, fresh outdoor air.  The fresh outdoor air becomes dry when it is warmed by the heat exchanger.  Introducing fresh, warm, dry air into your home evaporates and controls condensation (similar to a motor car windscreen warm air demister, or hair or clothes dryers).

Polluted, damp indoor air is continuously exhausted and replaced by 100% fresh outdoor air.  Excess humidity is positively exhausted to outside with the foul air and, in some conditions condenses on the heat exchanger plates (exhaust side only) to be disposed of by the HRV drain.

Continuous trickle ventilation with fresh, warm outdoor air dilutes indoor air contaminants, which are positively removed by the exhaust fan.  The result is an indoor environment that is always fresh and healthy.

The CLEANAIRE HRV performs best when winter conditions are at their worst, day and night.  In an average (heated) home, additional heat (or sunshine) is unnecessary.