A dehumidifier can be an essential tool in the fight against airborne moisture, which can damage your home and pose a risk to your health. But manufacturers base their water extraction claims on tests that might as well be conducted in a sauna. Check out our test results to see how they really perform over a Kiwi winter.
Types of dehumidifier
Desiccant vs compressor
Most dehumidifiers available here are compressor (refrigerant) models, which use the same tech as a heat pump or fridge. There are increasing numbers of desiccant dehumidifiers available in the market, though. They suck air through a rotating disk filled with moisture-absorbing material. They typically perform better in lower temperatures (below 12°C) than compressor models. The downside is that desiccant dehumidifiers can cost three times as much to run as their compressor counterparts.
Things to consider
We’ve found you need to spend at least $350 to snag a good dehumidifier. That said, they’re often on sale in spring and summer. If your budget is tight, consider a second-hand model.
Our energy efficiency scores indicate how much energy the dehumidifiers use to extract moisture from the air. A higher score means the dehumidifier uses relatively less energy. We also calculate the daily running costs of dehumidifiers, based on eight hours of continuous use. They range from 9¢ to $1.22 per day.
Like a thermostat for relative humidity, humidistats let you set desired humidity levels – the dehumidifier will work until the room reaches that level. The aim is not to remove the maximum amount of moisture – removing too much can result in dry skin, throat and eyes. We recommend 30–50% humidity to keep dust mites to a minimum, and reduce the growth of mould and bacteria.
The filters in some dehumidifiers can help keep the air healthier in a room. We haven’t tested manufacturers’ air-purifying claims, but if air health is important to you, select a model with a HEPA filter. These are the gold standard for filters, capturing particles down to 0.3 microns, including pollen and dust, as well as some bacteria and viruses.
Timers allow you to set the times a dehumidifier will switch on and off, giving it a set duty period each day. If a dehumidifier doesn’t have this function, you can use an inexpensive wall plug timer.
Noise and fan speeds
Most dehumidifiers, including all our recommended models, make upwards of 50 decibels (dBA) of noise. That’s enough to be annoying if you’re trying to watch TV or have a kip. For comparison, a reasonably quiet fridge produces about 40dBA. See our “quietness” scores – a model scoring above 70 is quieter than average. You’ll be able to dial back the volume if you choose a model with multiple fan speeds.
There’s a trade-off between mobility and tank size. Small water-collection tanks make a dehumidifier more compact and lighter, meaning they’re easier to carry around. Smaller tanks are also easier to lift up to a sink to empty than those of larger models. But the smaller the tank, the more frequently you’ll have to empty it. All dehumidifiers can be plumbed with a hose allowing continuous drainage – a good option for larger models.
Wheels and carry handles
Wheels and carry handles make your dehumidifier easier to move about the house. Larger models can weigh in excess of 20kg, making them a real chore to lug about, so wheels can become a necessity.
The dehumidification process generates some warmth, but extra heat speeds up the process. Desiccant models generate more heat than compressor models by design, as the extra heat is used to dry out the moisture absorbed. Some compressor models have a heating mode though, and they’ll suck up moisture faster than those without.
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