“Free heat” myth busted.

“Free heat” myth busted.

Consumer welcomes the results of the Otago University study on the heating and cooling potential of roof space air.

The myth of abundant free heat in the roof space is well and truly busted.

The Otago university study has monitored the roof space temperatures in kiwi bungalows (with the classic corrugated iron roof) and found that pumping in air from the roof space could often make your house colder in winter and hotter in summer than the usual inside temperature during those seasons.

For some time now Consumer has been concerned about the way some ventilation systems are advertised. It may well be hot enough to grill a sausage on a corrugated iron roof in February, but that’s not when homes need extra heat.

This study proves Consumer is right about heat in the roof space. We have been saying for many years on our website (www.consumer.org.nz ) that “there won't be warm air up there on frosty nights and cold grey winter days”.

Consumer looks forward to the end of advertising that makes misleading claims about the heating or cooling benefits from positive-pressure type ventilation systems. These ventilation systems should only be promoted on their ability to control condensation by providing adequate ventilation.

Condensation is a problem in many older house designs in New Zealand, and ventilation systems have been shown to reduce condensation in many types of houses.

Ventilation systems which use roof space air should not be advertised on their ability to provide winter heating or summer cooling in New Zealand houses. They also shouldn’t be promoted on their ability to control dust mites as an earlier study by the Wellington School of Medicine and Health Sciences showed no reduction in house mite numbers after ventilation systems were installed.

All three claims are now proven to be misleading.

For more information on ventilation and condensation: www.consumer.org.nz

ENDS

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