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 runs on the fan to draw indoor air over a heat exchange coil. The coil is almost freezing. The water in the air condenses on the coil and is drained. Another heat exchange coil reheats the air, that your dehumidifier exhausts in to the room.

A heat pump dehumidifier dumps heat lost from the compressor and fan motors into the air. It returns to the indoor air heat generated by the dehumidifier turning water vapour to liquid.

Chemical adsorbent dehumidifiers

This type of dehumidifier is designed 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 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 when 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 right into a pan or floor drain, drying the air. As the salt runs off with the water removed from the air, it must be replaced. The system does not have any moving parts.

If you try out this homemade dehumidifier, remember that salt is highly corrosive to metals and quite hard on the skin.

Dehumidifying ventilators

This kind of dehumidifier has a sensor-controller and exhaust fan. You set the sensor-controller to perform when humidity reaches a set level. A dehumidifying ventilator is specially 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 are not effective in hot, muggy weather, because they bring more outside air into the house. They may be effective in cold weather.

A dehumidifying ventilator depressurizes your basement, which can cause combustion gas spillage. Ensure that your heating contractor checks the venting for your gas furnace, hot water heater and wood-burning appliances. Consider using a carbon monoxide warning device if you use 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 is apparently the best time to buy: within the last few years dealers have held sales early in the spring with savings of $50 to $100.

Learn more  holds --which is measured in litres or U.S. pints a day--the more it costs.  Check over here  pay more for special features.

In 2000, you can expect to 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 little home 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 serious problems.

Running costs for both units are a comparable should they both have the same Efficiency Factor. Another section explains the Efficiency Factor.

Don't try to cut costs by investing in 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 some time will break down.

Get yourself a unit with a two-speed fan. They're quieter at lower humidity, which reduces the nuisance factor. Test all units in the store for noise level, particularly if you plan to utilize one in or near a bedroom.