Introducing Dehumidifiers and their Function
Dehumidifiers use a heat pump (much like an air conditioner's heat pump) or chemical adsorbents to eliminate moisture from the air without cooling the air.
A heat pump dehumidifier uses a fan to draw indoor air over a heat exchange coil. The coil is nearly freezing. The water in the air condenses on the coil and is drained. A second heat exchange coil reheats the air, which the dehumidifier exhausts in to the room.
A heat pump dehumidifier dumps heat lost from the compressor and fan motors into the air. Visit this website returns to the indoor air the heat generated by the dehumidifier turning water vapour to liquid.
Chemical adsorbent dehumidifiers
This kind of dehumidifier is made for hot, humid climates and is not really suited for used in Canada.
Chemical adsorbent dehumidifiers absorb moisture from the air with a "desiccant"--a drying agent such as for example silica gel. The desiccant is on a heat exchange wheel. A separate air loop dries the wheel and exhausts the hot, damp air outdoors through special ducting.
A chemical adsorbent dehumidifier uses more energy when compared to a heat pump dehumidifier. It really is only cost-effective when it uses gas for heat exchange--and then only if natural gas is available at a minimal summer rate.
Homemade dehumidifier
Some inventive people use bags of road de-icing salt to soak up moisture from the air. The wet salt solution drips into a pan or floor drain, drying the air. Because the salt runs off with the water removed from the air, it should be replaced. The system has no moving parts.
If you try this homemade dehumidifier, remember that salt is highly corrosive to metals and quite hard on your skin.
Dehumidifying ventilators
This kind of dehumidifier has a sensor-controller and exhaust fan. You set the sensor-controller to run when humidity reaches a collection level. A dehumidifying ventilator is particularly effective if the humidity source is in your basement.
Dehumidifying ventilators don't recover heat however they use less electricity than heat pump dehumidifiers. They're not effective in hot, muggy weather, as they bring more outside air in to the house. They could be effective in winter.
A dehumidifying ventilator depressurizes your basement, that may cause combustion gas spillage. Ensure that your heating contractor checks the venting for your gas furnace, water heater and wood-burning appliances. Contemplate using a carbon monoxide warning device if you install a dehumidifying ventilator.
Choosing a Dehumidifier
Dehumidifier purchase costs
Heat pump dehumidifiers are complex, low-production machines and so are not low-cost items. Spring appears to be the best time to get: in the last few years dealers have held sales early in the spring with savings of $50 to $100.
The more water a dehumidifier holds --which is measured in litres or U.S. pints a day--the more it costs. You pay more for special features.
In 2000, you will probably pay between $200 and $250 for a unit rated at 10 L (21 U.S. pints or 2.1 imperial gal.) a day--suitable for a small house with a moderate moisture problem. The price rises to between $250 and $350 for a unit with a capacity of 20 L (42 U.S. pints or 4.3 imperial gal.) a day--suitable for a big house with more severe problems.
Running charges for both units are a comparable if they both have the same Efficiency Factor. Another section explains the Efficiency Factor.
Don't try to cut costs by buying a unit that will not have automatic defrost. In case a room is too cool, a dehumidifier can frost over and prevent removing moisture. A frosted-over dehumidifier left running for years will break down.
Get yourself a unit with a two-speed fan. They are quieter at lower humidity, which reduces the nuisance factor. Test all units in the store for noise level, particularly if you plan to use one in or near a bedroom.