Heating and Cooling

Heat Pumps

For homes in climates where cooling and heating requirements are moderate, heat pumps can be a strong energy-saving alternative to conventional forced-air furnaces and air conditioners. Using refrigeration technology instead of fuel combustion to provide warmth and cooling, conventional heat pumps move heat from cold to warm spaces - and vice versa - to cool a warm house in the summer and heat a cool house in the winter. By transferring heat instead of producing it, they can do their cooling or heating far more efficiently than furnaces and air conditioners.

An air-source heat pump, the most common type, does this work by transferring heat between a house and the outdoors. In moderate climates where electricity is used for heating, energy bills can be trimmed by as much as 30 to 40 percent. This efficiency drops off significantly at low temperatures because not enough heat can be extracted from the ambient air to provide significant warmth. In this situation, auxiliary heat from non-efficient heating elements in the system is usually necessary.

Air-source systems require ductwork like that used in a typical forced-air system. Homes without ductwork can be heated and cooled by mini-split heat pumps.

An entirely different type of heat pump is the geothermal (ground-source or water-source) heat pump. This transfers heat between the ground or a nearby water source to your house. Though this type can be costly to install, it operates very efficiently even in climate extremes.

This section of HomeTips will give you the information you need to determine if a heat pump is right for you, as well as valuable maintenance and repair tips for your heat pump.

Air Conditioners

Are multiple room air conditioners causing your electric bills to skyrocket? Or, perhaps worse, is your house virtually unlivable during summer because of the heat and/or humidity? Maybe it's time to consider central air conditioning.

Central air conditioning, also called "central air" in the United States and "air-con" in the United Kingdom, is a system that cools more than one room in a house or building (in most cases, the entire structure). A conventional air-conditioning system blows cooled and/or dehumidified air through ductwork to deliver it throughout the interior room spaces. In most cases, it employs an air handler (blower) and ductwork of a forced-air furnace for this cool-air delivery. This is, of course, different than a portable room or window air conditioner, which is meant to cool only a single room.

Air conditioners use refrigeration principles to cool the air. As discussed in How a Central Air Conditioner Works, a condenser, compressor, and evaporator work together to do this job. A typical split-system air conditioner has a compressor and condenser located outdoors and an evaporator unit mounted on the air handler or furnace. A package A/C system combines all of these components in one outdoor unit.

A central air unit draws room air through return-air ductwork, cools, dehumidifies, and filters it, and then blows it back into the rooms through air-supply ductwork. The A/C unit is controlled by a thermostat, which turns the unit off and on as needed. In most cases, the same thermostat doubles for both the air-conditioning and heating system.

Be aware that retrofitting an existing home with central air conditioning may not be an easy nor inexpensive project. Ductwork must run from the air handler to the rooms and, to do this, must usually be routed through the attic or under the floor. If your home is not suited to this type of installation, room air conditioners may be a better solution.

For information on room or portable air conditioners, see Air Conditioners: Room.