Dampness is a problem in many rentals. A survey by Statistics NZ found almost half of renters battled excess moisture in their homes. Mould and dust mites thrive in damp conditions, which can lead to people suffering allergies, asthma and severe respiratory illnesses.
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There’s no quick fix for tackling moisture. You need to identify where the dampness is coming from and try to stop or minimise it as best you can.
Ventilation helps remove moisture and airborne pollutants from the home. Older homes, which are often draughty, usually have fairly good natural ventilation. Newer houses are often fairly airtight, so require more conscientious airing.
Moisture build-up in the home isn’t just caused by rainy days and leaky roofs – our day-to-day living contributes too. Washing, cooking and even breathing all add moisture to the air.
Here are some common sources of moisture in your home.
Also see our tips on managing mould.
If you’re ventilating and heating the home properly, but it’s still damp, look at getting a dehumidifier. Be aware they can be expensive to run. Here are our tips for getting the most out of a dehumidifier:
Dehumidifier manufacturers base their water extraction claims on tests conducted at about 30°C and 80% relative humidity (RH). That’s a valid comparison if you live in the tropics, but in New Zealand, those conditions are nothing like the winter climate in your home.
We tested dehumidifiers in conditions ranging from 8°C and 90% RH to 16°C and 65% RH, conditions much more typical of a New Zealand winter. We found actual performance was far lower than claimed.
Dehumidifiers are second only to heat pumps in terms of heating efficiency. When water is turned from liquid to vapour, heat has to be added but there’s no temperature rise. This is called the “latent heat of evaporation”. The reverse happens when water vapour condenses to a liquid – the latent heat is released. When a dehumidifier condenses the water vapour in the air back to a liquid for draining, the latent heat in the water vapour is released, helping heat your home.
These are the three dehumidifiers that topped our tests.
Avg price: $499
Bottom line: The desiccant technology in the Dimplex GDDEKD9 makes it the best performing dehumidifier that we have tested. The overall score was hurt by the increased running costs but we think the increased costs are not of great concern when you have such an outstanding performer. The heat output is also equivalent to a 1kW heater.
Avg price: $699
Bottom line: The Panasonic F-YCL27N is a very good all-rounder. It’s incredibly efficient, easy to use and performs well for water removal. This model does suffer in lower temperatures so it would be best suited to rooms where you know the temperature won't drop too low. The model is very heavy but didn't prove too hard to move around on its wheels.
Avg price: $399
Bottom line: The Suki WDH1150DBH dehumidifier is a good performer. It performs well at lower temperatures, which bucks the trend of most compressor models. The larger 4.9L tank capacity means fewer trips to empty the water down the drain.
Our free guide provides advice and tips on what you can do to make your home warmer, cosier and cheaper to heat.
This report is available free to consumers and was produced with funding from the Ministry of Health.
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