Heating, Cooling and Air Quality for the Home

Move the air, change its temperature or clean it: name the problem first

The area is split by the problem a product solves. Fans and circulators move air without changing its temperature, air conditioners and space heaters remove or add heat, and humidifiers and dehumidifiers adjust moisture. Purifiers and filters take particles and odors out of the air. Decide whether the room is hot, cold, dry, damp or stuffy, then go to the matching aisle, such as space heaters for a cold corner.

Room size matters in every aisle, and each uses a different yardstick. Air conditioners are rated in BTU per hour, heaters in watts, and purifiers and humidifiers in the square footage of room they can treat. Pick a rating that matches your floor area and ceiling height rather than the biggest number on the page, because an oversized air conditioner cools fast but shuts off before it has dried the air, and an oversized humidifier can leave a room damp.

Consumables and safety: the details that decide long-term use

Many climate products depend on a part that wears out: HEPA and carbon filters in purifiers, wicks in evaporative humidifiers, and pre-filters that catch hair and dust. These are model-specific, so note the filter code before you buy the machine and make sure replacements, such as those under replacement air filters, are easy to find. For heaters and fireplaces, look for tip-over shutoff, overheat protection and a thermostat, and plug them directly into a wall outlet rather than a thin extension cord.

Questions about Heating, Cooling and Air Quality for the Home

What does the square-footage rating on a purifier or humidifier mean?

It is the room size the maker rates the unit to treat, normally a closed room with a standard ceiling. For an open-plan space or high ceilings, choose a rating clearly above your floor area, or use more than one unit.

Is it safe to run a space heater from an extension cord?

Most manuals say to plug a heater straight into a wall outlet, because heaters draw a lot of current and a thin or long cord can overheat. If a cord is unavoidable, it must be heavy-duty and rated above the heater's wattage.

Do I need a humidifier or a dehumidifier?

A humidifier suits dry air: static shocks, dry skin and cracking wood in heated winter rooms. A dehumidifier suits damp air: a musty smell, condensation on windows and mold spots, common in basements. A small hygrometer confirms which problem you have before you buy.