The rate of heat loss/gain is determined by the R-Value (resistance) of the building's walls, ceilings, floors and windows.  Select the appropriate insulation values from the choices below.

  The heating system will be calculated to maintain an indoor temperature of 68° F.  A functional low temperature will be needed for the computations.  This will be the normal low temperature for your area.  It will not be the lowest temperature ever recorded for the region, but a temperature that is normally experienced between 1% and 3% of the time.   Check with your town or state's building department if you do not know this figure, our click here for an estimate for your area.

The cooling system will be designed to maintain an indoor temperature of 78° F at 55% relative humidity and an outdoor temperature of 93° F.  A functional high temperature will be needed for the computations.  This will be the normal high temperature for your area.  It will not be the highest temperature ever recorded for the region, but a temperature that is normally experienced between 1% and 3% of the time.  Check with your town or state's building department if you do not know this figure, our click here for an estimate for your area.

This represents the outdoor humidity level in your geographic location.  If you know this number, enter it below.  If not, check with your local building department or click here for an estimate for your location.

  Certain construction types and climates, especially waterfront regions, experience minimal temperature drops during the overnight period.  This effects the ability of the building's mass and attic space to cool down.  Is this true for the location of this house?

Please select the type of house you will be calculating the heat load for.