NovelAire ComfortDry 250
Whole House Dehumidifier Review

The NovelAire ComfortDry 250 Whole House Dehumidifier is an innovative and possibly unique concept for residential dehumidification. The ComfortDry 250 employs NovelAire's advanced desiccant technology to remove unwanted moisture from the home environment.

Traditional refrigerant dehumidifiers, the type most commonly found in the home, remove moisture by condensing water vapor on to a cold surface. The liquid water produced is collected in a water collection container or drained to a nearby outlet.

A desiccant dehumidifier captures water in a desiccant material. A desiccant material is one to which water molecules "bind" themselves by means of a chemical process. This process is known as adsorption, to distinguish it from absorption, the process by which water enters a porous material, like a sponge, and is "trapped" within the tiny spaces within that material, a physical rather than a chemical process.

The desiccant, making up the larger part of a slowly rotating wheel, will release the water bound to it if heat is applied, a process often referred to as "reactivation". During every cycle of the wheel a proportion of it is placed before a stream of warm air and reactivated. This allows the wheel to adsorb more water during each rotation.

An innovative feature of this NovelAire dehumidifier is that the heat source for reactivation is hot water. The use of water allows greater energy efficiency than using electric power to heat the air. Depending upon the cost of heating the water this NovelAire dehumidifier will operate at an energy factor ranging from 3.5Ltr/KwH to 5.0Ltr/KwH, making it one of the most energy efficient whole house dehumidifiers on the market.


The NovelAire ComfortDry 250 is not only more efficient than a refrigerant dehumidifier but is, in some respects, more effective. Because a desiccant dehumidifier does not use refrigeration to condense moisture from air it does not suffer from ice formation inside the unit. For this reason it is capable of low temperature operation without the use of a defrost system and to lower ambient temperatures.

Desiccant wheels can continue to remove moisture to levels below those attainable by refrigerant units designed for residential applications. While it is not usually necessary or desirable to maintain relative humidity at a level lower than 45% to 55% the fact that the NovelAire ComfortDry 250 is capable of reducing it much lower means that the moisture extraction it is achieving at that level is more consistent and reliable than that of a refrigerant dehumidifier. This allows the unit to deliver more precise humidity control and to do so with greater energy efficiency.

Humidity is monitored and maintained to a pre-set level by the humidistat incorporated in to the unit. The humidistat control is wall-mounted, at a convenient location and may be set to your preferred level. A level of relative humidity in the range of 45% to 55% is generally recommended for personal comfort and to inhibit mold and mildew growth. To deter allergen producing dust mites a setting of at least 50% is more reliable. Extremely low relative humidity is not advisable in living spaces and at 30% or less is liable to cause discomfort.

The NovelAire ComfortDry 250 is designed and recommended for permanent installation and requires ducting in order to operate throughout an entire home. The unit may be integrated in to an existing air-handling system or may be installed in stand-alone mode with its own dedicated ducting. Once installed, with the humidistat set at the preferred level the ComfortDry 250 will operate automatically to maintain a constant level of relative humidity.

Even when integrated with the HVAC system the unit operates independently of the air-conditioning. The advantages are that the unit can function when the air-con is not needed. It also responds to the level of relative humidity whereas the air-con cycles on and off according to the temperature.

An advantage of any whole house dehumidifier is that by reducing the relative humidity it lowers the perceived heat in the house. This is simply because the body's heat control mechanism, the evaporation of sweat, is more effective when there is less moisture in the air. A benefit is that it now becomes possible to set the thermostat on the air-con a few degrees higher, with no loss of comfort, saving energy.

A feature of desiccant dehumidifiers is the simplicity of the working parts. The high-tech part of the unit is the desiccant wheel; NovelAire is at the cutting edge of desiccant technology. The wheel is expected to last for the life-time of the dehumidifier and comes with a five year warranty. A refrigerant dehumidifier needs a compressor, evaporator and condenser coils for the cooling process and it is these parts of the system that are most likely to suffer from breakdown. The absence of these relatively fragile, heavy and expensive components makes a desiccant dehumidifier inherently more reliable than a refrigerant model.

The use of hot water to heat the air which reactivates the desiccant wheel is an innovative feature of the NovelAire ComfortDry 250 which contributes to its energy efficiency. The water may be sourced from anywhere and if solar heated or waste hot water is used the energy savings are increased. It is this feature which is the main contributor to the variable energy factor of 3.5Ltr/KwH to 5.0Ltr/KwH referred to earlier. Even 3.5 is hard to beat and if low or no cost hot water is used this unit becomes one of the most, possibly the most, energy efficient whole house dehumidifiers available.

The NovelAire ComfortDry 250 will remove 105 pints of moisture per day from the air, at the AHAM (Association of Home Appliance Manufacturers) recommended testing conditions of 80°F (27°C) and 60% relative humidity. At different levels of one or both of these conditions water extraction rates will vary.


Brand NovelAire
Model NovelAire ComfortDry 250 Dehumidifier
Application(s) Whole House
Suitable for Areas up to 3000 sq ft
Portable No
Carrying handles No
Wheels/casters No
Weight (lb) 137
Dimensions, inches (WxDxH) 18 x 39 x 20
Dehumidification process Desiccant
Water extraction (80°F 60%RH) 105 pints per 24 hrs
Water container capacity (pints) N/A
Container full indicator N/A
Auto-power cut off when full N/A
Continuous drainage option N/A
Operating temperature Range N/A
Blower 300 CFM
Anti-frost N/A
Electronic controls Yes
Humidistat Yes
Variable fan speed settings No
Noise level Not Rated
Power input 5.6amp/120v


High water extraction rate

Superior performance at low temperature/low relative humidity

Precise humidity control

Highly energy efficient

Reduces cost of air-conditioning


No condensate to dispose of


Initial purchase cost

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