If you are installing new equipment, in addition to making choices about energy efficiency you will need to decide whether to pay extra for various features. Below is a summary of the types of add-ons. We’re admittedly scratching the surface of the heating-and-cooling-equipment-options world here, but these are the major “Do you want this or not?” questions you’ll face.

  • Variable-speed blowers—Indoor fans (blowers) and/or outdoor fans of central air conditioners, heat pumps, and furnaces can be equipped to run from slow to fast, depending on need. The units are programmed to keep conditioned air continually moving at the lowest flow possible. These setups minimize cycling on and off (which contributes to wear and tear), dramatically help systems maintain consistent temperatures throughout different areas of homes, reduce energy usage, and decrease noise.
  • Variable output—Furnaces with this feature automatically select how much heat to generate (usually from between two levels); air conditioners and heat pumps with variable output automatically select how hard their compressors need to work to deliver conditioned air. Like variable-speed blowers, this feature lets equipment deliver warm or cool air continuously for longer periods of time, meaning equipment doesn’t have to cycle on and off frequently.
  • Programmable thermostats—These devices provide an easy way to save energy, as long as you actually program them (which most homeowners who have them don’t). If your home is unoccupied during the day, you can save five to 15 percent per year on energy bills by turning down the heat by 10F° to 15F° while you are away. Obviously, you’ll want to get a model that is easy to use. A misconception associated with programmable thermostats is that when it is time to return the temperature to normal, the furnace has to work so hard, and use so much energy, that little energy is saved. Much research has shown this to be untrue.
  • High-efficiency air filters—These assemblies, which use electrical charges to attract and trap particulates, can also reduce the amount of dust blown through systems. But there’s little evidence that they actually improve indoor air quality.
  • Desuperheaters—Some high-efficiency heat pumps can be equipped with these devices that capture waste heat generated from heat pumps during cooling mode and use it to heat water. Desuperheaters heat water two to three times more efficiently than conventional electric water heaters.