• A fan collects air from the surrounding space and pulls it into the dehumidifier.
  • As the air passes through, it comes into contact with the dehumidifier’s cooled coils. These coils use condensation to pull moisture from the air. The collected moisture remains on the coils and drips into the dehumidifier’s reservoir.
  • The dehumidifier then reheats the air and exhausts it back into the room.

A dehumidifier usually has a removable plastic reservoir to collect the water; most buckets also have a place where you can hook up a hose so the water can drain straight into a floor drain or pump. This frees you from having to remember to periodically dump the water. Don’t worry too much about the reservoir overflowing – most dehumidifiers also have an automatic shut-off. If you’re using a dehumidifier in extremely moist conditions, however, or if you need to keep your dehumidifier on all the time, you should look into a unit with a built-in condensate pump, which regularly pumps water out of the unit’s reservoir rather than simply relying on gravity to empty it as a hose does.

Many dehumidifiers also have a humidistat, which allows you to set your desired level of relative humidity. A humidistat has two parts: a sensing element and a relay amplifier. The sensing element includes two alternate metal conductors, and changes in relative humidity will cause electrical resistance between those conductors. The relay amplifier measures this resistance and sends a signal to turn the dehumidifier on or off. These basic components add up to a device that may make your home feel a whole lot better.

We stock both refrigeration type dehumidifiers as well as self-regenerating desiccant type dehumidifiers. With the refrigeration type dehumidifiers a compressor is used to pump refrigerant through a closed piping circuit that generates a hot condenser surface on the high pressure side and a cold evaporator surface on the low pressure side. Humid air passes over the cold surface causing moisture in the air to condense into water droplets just as dew forms on the grass or window panes on cold mornings. When the water vapour changes from a gas into a liquid the cold surface absorbs a large amount of energy and the refrigerant transports this energy to the hot surface. The air leaving the cold surface is then heated as it passes over the hot surface so that the air dryer supplies warm dry air.

With the desiccant dehumidifiers the process air passes over a warm surface and through the warm drying segment of the chemical rotor where the moisture molecules separate and bond with the surface of the rotor so that dry warm air comes out. Moisture is removed from the rotor by heating a small portion of this air and passing it through the regen segment of the rotor where the hot air breaks the chemical bond releasing the water vapour so that concentrated humid air leaves the rotor regen segment. This warm moisture laden air passes over a relatively cool surface causing the liquid to condense out and collect in the water tank. All the dehumidifiers that we offer are self-regenerating and do not require chemical additives to sustain the performance.

Both the refrigerant and desiccant dehumidifier type models have the condensate water collected in a canister that can be manually emptied, alternatively the condensate can be connected to a drain point where it drains directly without requiring the canister to be emptied. If a canister is full, then the dehumidifier automatically switches off until it has been emptied and replaced.