Types of humidifiers

Evaporative humidifiers are prob­ably the most common and come in two types: cool mist and warm mist. They’re simple machines consisting of a box that contains a reservoir of water, a wick (or filter) and a fan. The wick absorbs water, the fan blows air across the wick and expels the moisture-laden air into the room. These are referred to as “cool mist” humidifiers.

A “warm mist” humidi­fier has an internal heating element that boils the water that disperses as steam. The boiling kills most waterborne bacteria and mould. And because the process creates steam they don’t use fans, mak­ing them quieter to run. However, you may want to avoid these if there are young children in the home as they can topple over and burn tender skin.

An ultrasonic humidifier uses ultrasonic vibration to create a super-fine cool mist. Like warm mist humidifiers they don’t use fans, but they do produce a fine white dust from the minerals present in your tap water. The dust settles around the room. Using dis­tilled water can substantially reduce the dust.

If you can’t decide between a warm and cool mist humidifier you’re in luck; some models feature both warm and cool mist capabilities in one unit.

Formats to choose from

Evaporative and ultrasonic humidi­fiers are available in personal, tabletop (a.k.a. desktop) and console (a.k.a. floor) sizes. All three are essentially portable humidifiers and can be car­ried or rolled around the home. While they all perform the same basic function of humidifying the air, they can have a range of additional features, including an empty-tank indicator, wick replace­ment indicator (for cool air evaporative models), automatic shutoff, remote con­trol, night light, diffuser (which emit essential oils into the air), UV light (which destroys microbes and bacteria and can also de-chlorinate and de-ozon­ate the water), and built-in humidistat (which monitors the room’s humidity level and shuts the unit off at a pre-cho­sen humidity level).

Whole house (furnace-mount) humidifiers are available in evaporative and steam formats.

The personal model is best when used up close and personal. They have the smallest tank sizes, generally under a litre. Some have multiple speed settings. Higher speeds deliver more humidity but can significantly decrease the run time before you need to add more water to the unit. The Evapolar, for example, which I use at my desk, needs refilling every three hours or so on its high-speed setting, and every seven or eight hours on its lowest speed setting. Some personal models can be powered from a USB port on your desktop computer or smart device.

Desktop models are suitable for small rooms up to a few hun­dred square feet. Most are in the two- to four-litre tank size and can run for up to 15 hours at the slowest speed setting without need­ing to refill the tank. They’re available in an astounding range of shapes and colours to suit your decor.

A console model is better suited for large rooms. They’re avail­able in a wide range of tank sizes and are a good choice if you live in an apartment, condo or house with an open-floor plan. If you live in a multi-storey house you’d want one for each floor, or at least a model with casters or handles so you could easily move it around the house. Choose a model rated for the square footage of the largest room you’ll use it in.

If you don’t relish moving a console humidifier from room to room and you have a house with a heating duct system, consider installing a furnace-mount humidifier. They connect to your home’s heating and air-conditioning system, which is usually mounted to a return air duct. Evaporative (flow-through and rotating drum) models are the most popular types, while steam models are less common. A water supply is connected to the humidifier. The water is dispensed over an absorbent evaporator pad. Warm dry air from the furnace passes over the pad, absorbs moisture and then circulates the warm moisture through the duct work. A humidistat (similar to a thermostat that you use to set the heat level) enables you to control the humidity level. Unless you have experience with electrical wiring, water lines and ductwork, installation is best done by a plumber or HVAC technician.

Evaporative Coolers

Also known as swamp coolers, evaporative coolers are somewhat similar to humidifiers. They’re either located outside the home or window-mounted. A fan draws in warm outside air and passes the air through a wet evapo­rator pad. The moistened air loses heat and cooled air is blown into the home. They work best in hot, dry areas where the relative humidity is around 30%. Similar to humidifiers, they do add some moisture to the air.

Moisture breeds bacteria

Regardless of what you hear or read about any of these mod­els, they all need rigorous scheduled maintenance, even ultrasonic humidifiers and those with UV light technology. At the minimum, you should rinse out the tank daily and clean it with a mild bleach solution weekly. Change the wick and any other filters according to the manu­facturer’s recommended schedule.