Calculating Savings

Adding Insulation

When you increase the insulation value of your attic or walls you will save energy.  How much depends on how many square feet, the initial insulation level, the final insulation level and where your home is located.  The following formula is used.

Formula

AREA (sqft) x ( 1/Initial R-value - 1/Final R-value ) x 24 x HDDZ x Cost/Unit of Heating Fuel / Btu/Unit of Heating Fuel / Heating System Efficiency = Annual Dollars Saved

Variables Defined

Area = Length x Width of area to be insulated
Initial R-Value & Final R-Value = Figure out based on R-Value Table.
HDDZ = Heating Degree Days. See HDDZ Table.
Heating Fuel Cost = Get from your bill by dividing units / cost.
Btu/Unit = Get from Fuel Btu Table.
Heating System Efficiency = Get from Heating System Efficiency Table.

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Last Updated: 01/21/2007