What You Need to Consider for Your Heating System

By Jody Howe
Senior Energy Specialist

Did you know your home structure is also considered the building “shell”? Heating contractors model the existing condition of your shell for sizing its heat load. This heat load is the amount of heat energy in BTU’s needed to comfortably heat your home.

This means in construction terms the insulation in attic, floor and walls are rated, as are the windows. These building parts are  where areas heating and cooling is lost or maintained. Insulation is rated by its “R” value; Resistance to heat FLOW, so a higher R value equals higher resistance.

Windows are rated in a U factor; referring to the thermal transmission or the amount of heat flow through a square foot of building cross section. The lower number being better and resists heat transfer.

Combining all these measurements the HVAC specialist determines if more or less BTUs are needed to heat your home. This is the “sizing” process that CEC heating contractors provide from the existing elements in your “shell”. The larger a system tonnage the more BTUs it will provide. The key is to “size right” for the home. This step is also required by the Bonneville Power Administration and CEC Heat Pump Program.

It is important CEC members understand the process. This gives you the knowledge to understand the elements that create comfort in your home.

So before you buy a heat pump, consider:

  • Air sealing before adding insulation to your attic, crawl space, and walls.
  • Adding weather stripping around doors and caulk around windows for air sealing efforts.
  • Properly sealing the ductwork throughout your home.
  • Properly insulating the ducts in crawlspaces and attics.