How Things Work
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Air Conditioning System

To cool your home, air conditioners use a chemical known as a refrigerant to transfer heat to the outside air. To perform this function, an air conditioning system has three main mechanical components.

Air Source Heat Pumps

In size and appearance, a heat pump looks like a central air conditioner. But unlike a central air conditioning system, which only cools a home, a heat pump provides heating and cooling.


Boilers in a home generate hot water or steam for hydronic heating systems such as radiators, finned-tube baseboard heaters, radiant floor heating, radiant panels (towel warmers), kick space heaters and indirect water heaters.

Ductless Mini-split Systems

Unlike conventional air conditioning systems that use a system of ducts to deliver conditioned air throughout your home, ductless systems use a wall or ceiling-mounted blower to deliver cool air to a room.


Ductwork is composed of two parts: supply and return. Supply ducts deliver air to each zone in a home.

Energy Recovery Ventilators

Energy recovery ventilators (ERVs) and heat recovery ventilators (HRVs) are mechanical ventilation systems that use fans and other technology to maintain a constant flow of fresh outdoor air into the house, while exhausting stale indoor air.

Furnaces: How They Work

Before selecting a furnace for your home it is important to understand how they work so you can make an informed decision.

Geothermal Heat Pumps: How They Work

Geothermal heat pumps are similar to air-source heat pumps, but instead of using heat found in outside air, they rely on the relatively constant heat of the earth (thermal energy) to provide heating, air conditioning and, in most cases, hot water.

How Humidifiers Work

Air in your home that is too dry can be uncomfortable to breathe, can cause static build-up, dry itchy skin, parched throat, and can damage wood products like flooring, pianos, picture frames and cabinetry.

Hydronic Heating

One method for warming an indoor space is known as hydronic heating. This method of heating circulates hot water through plastic tubing, baseboards, or radiators to provide heat in an indoor space.

Mechanical Air Filters

Mechanical air filters (also called Media Air Filters) use filter media to remove particles from the air stream in HVAC systems.

Small Duct, High-Velocity Air Conditioning Systems

Small duct, high velocity (SDHV) air conditioning systems are similar to conventional split system air conditioners that consist of an outdoor condensing unit and an indoor coil unit.

Swamp Coolers

Evaporative coolers, often called "swamp coolers,” are cooling systems that use only water and a blower to circulate air.

Ultraviolet Light Treatment Equipment

If you suffer from asthma or allergies, have a smoker in the home or have a mold problem, you may want to consider having ultraviolet light treatment equipment installed in your heat pump or air conditioning system.

Vent-Free Gas Heating Appliances

A vent-free gas heating appliance operates without a chimney, flue or vent, so you can install them just about anywhere in your home without making a hole in the wall or roof.

Water Heaters: How They Work

Manufacturers of water heaters offer a breadth of types and models that allow you to make the right choice for your home.

Zoned Heating and Cooling

Zoning a home is actually quite simple. If you have a central forced-air heating and cooling system in your home, it uses a system of ducts that move air throughout the rooms in your home.