Source: Canada Mortgage and Housing Corporation

The dehumidifier heat pump

Dehumidifiers use a heat pump (like air conditioners) or chemical absorbers to reduce the water content of the air without cooling it.

A dehumidifier heat pump directs the air inside, through a fan, a heat exchange coil. The coil is almost freezing. The water contained in the air condenses on the coil, and then is discharged.

A second coil heat exchanger heats the air, the dehumidifier rejects the room. The dehumidifier heat pump returns in the air the heat generated by the compressor and the fan motor, plus there reject the heat produced by the dehumidifier by passing the water vapor in the liquid state.

The Chemical adsorbent dehumidifiers

Being designed for hot and humid climates, this type of dehumidifier is not really suitable in Canada.

The dehumidifier chemical absorbent absorbs water from the air using a "desiccant" product having the property of drying, such as silica gel. The desiccant is located on the wheel of the heat exchanger. A separate sealed air system dries the wheel and discharges hot and humid outside air through special ducting. The chemical absorbent dehumidifier consumes more energy than a heat pump dehumidifier. It turns an efficient choice when using natural gas for heat exchange - and then only if natural gas is available at a low price in the summer.

The house dehumidifier

Some people use the inventive spirit bags of de-icing salt to absorb moisture from the air. The wet salt solution flows in a tank or in the floor drain, while drying the air. Because salt is flowing with water removed from the air, must be added. This technique has no moving parts. If you try this homemade dehumidifier, remember that salt is highly corrosive to metal and highly abrasive to the skin.

The dehumidifying ventilator

This type of dehumidifier comprises a sensor control device and an extractor fan. You set the sensor control device for the dehumidifier to operate when humidity reaches a set level. A dehumidifying ventilator is particularly effective if moisture comes from the basement of the house.

However, consuming less electricity than a heat pump dehumidifier, dehumidifying fan does not recover heat. It is not effective in hot and humid weather, as they outside air into the house. By cons, it can be effective in cold weather.

A dehumidifying ventilator depressurize the basement, risking thereby to cause the discharge of combustion gases. In such cases, do check with your heating contractor evacuation of furnace and gas water heater and any wood-burning appliance. Consider using a carbon monoxide alarm if you count install a dehumidifying fan.

Cost of dehumidifiers

The heat pump dehumidifiers are complex machines, on a small scale, accompanied by a high price. Spring seems to be the best time to acquire. Indeed, in recent years, merchants held in spring balances for savings of 50 to $ 100.

The price of the dehumidifier is based on its capacity is measured in liters or pints per day, and its particular characteristics.

In 2000, you can expect to pay between $ 200 and $ 250 for a unit with a capacity of 10 L (21 U.S. pints or 2.1 imperial gal) per day, which is well suited to a small house with a problem moderate humidity. The price rises between 250 and $ 350 for a unit with a capacity of 20 liters (42 pints or 4.3 imperial gal) per day, which is suitable for a large house facing more serious moisture problems.

The cost of operation of the two devices is equivalent, since both are bound by the same factor of efficiency. The next section discusses also the efficiency factor.

Do not try to save money by buying one without an automatic defrost system. If the temperature of a room is too cool, a dehumidifier can frost over and stop removing moisture. A frosty dehumidifier continues to operate for a long time finally breaking down.

Pick up a device with a two-speed fan. Such a device is running silently when the humidity is low. Check all devices in the store, especially if you intend to use in a room or nearby.

The efficiency factor

The efficiency factor (EF) is a guide to the cost of running dehumidifiers. The efficiency factor is usually indicated in the product brochure or the owner's manual, if not on the label behind the tray label.

The EF represents the amount of water in liters, a dehumidifier able to draw air at a temperature of 27 ° C (80.6 ° F) and a relative humidity of 60% for each kilowatt hour (kWh ) of electricity. If power is restored to 8 cents per kilowatt hour, valid cost in most regions of Canada, the unit with an EF 1.2 will extract 15 L (32 U.S. pints or 3.3 imperial gal) for each dollar electricity. An improved model, with an EF of 2.4 succeed in extracting 30 L (63 U.S. pints or 6.5 imperial gal) of water for every energy dollar.

Since the condensation releases heat, the dehumidifier acts as a heat source. The situation may be useful in spring or autumn, when the temperature of the basement is usually fresh. In midsummer, the heat from the dehumidifier is unproductive.

Total Cost

The total cost includes the purchase, costs of operation, maintenance and repair prices.

The table below shows an effective dehumidifier with an EF of 1.8 saves $ 36 per year on operating costs compared to a conventional dehumidifier. These savings quickly offset the additional cost of a more efficient unit.

FE dehumidifier 1.2 1.8
Number of days of use per year 80 80 80
Extracts liters per day 20 L 20 L
Annual electricity costs 107 $ 71 $

Annual savings of $ 36

When choosing a dehumidifier, make sure you know:

1.La capacity you need for your home, most manufacturers have tables for you to make your choice.

2.The purchase price.

3.The efficiency factor (EF).

4.Si you need to empty the tank or the unit is autoévacuation. A dehumidifier is autoévacuation what is better, since you do not have to worry about emptying the tank every day.

5.If equipped with automatic defrost. The unit should have one.

6.The noise level at low speed and high speed.

7.La reputation of the manufacturer with regard to the quality and warranty.

8.The service you can get the dealer or an authorized dealer.

Where to place the dehumidifier

If your home is equipped with central heating and forced air cooling to ensure a continuous flow of air, no matter where you intend to place the dehumidifier. It will extract air substantially the same amount of water, regardless of where it is found.

The preferred place where the dehumidifier is probably the laundry, arranged on a shelf above the laundry tub, so that the condensate can drain directly into the sink area. There are two reasons for this place: the room can be hot and the dehumidifier is more effective when the air is warm, and in addition the sink nearby.

If your basement is cool, you should use a dehumidifier autoévacuation and place it where it can drain condensate.

If heating is hot water baseboard or insured, place the dehumidifier in place showing the worst moisture problem, provided it is not a cold place. By cons, if the unit is equipped with an automatic defrost, the cool suit him very well.

Place a dehumidifier in a room is not necessarily a good idea. Indeed, the device may be too noisy and you have to empty the tank every day.

Tips for maintenance and operation

Clean the internal filters periodically. Start by cleaning every two weeks. If they are very dirty, then you can clean them less often. Vacuum the coils in the spring and fall if they get dirty.

You can not settle once and for all orders of the dehumidifier. During the hot and humid summer days, set the dehumidifier to withdraw more water. By cons, lower the setting for the unit withdraws less in the spring, fall, or dry and clear weather in the summer.

When the dehumidifier does not solve the problem

The dehumidifier can not alone address the serious moisture problems in your home. You must, first and foremost, find the source of moisture. Take steps to reduce the amount allowed in the house or to stop it completely.

Remember that a dehumidifier is useful, but it is not magic.

Although this information is based on current knowledge of housing experts, he intended only to provide general information. Readers assume responsibility for actions or decisions made in reliance on the information contained in this book. It is up to readers to consult appropriate professional resources and experts in the field to determine whether, in their case, the information, materials and techniques are safe and suitable for their needs. The Canada Mortgage and Housing Corporation assumes no responsibility for any consequence arising from use of the information, materials and techniques described in this book.