After that you will have a good picture of what your house lost in energy through the year.
Savings due to roof insulation.
In order to get a reasonable answer one must do some testing and compare to the energy used by the house with local weather.
The savings and payback vary substantially depending on the existing level of insulation but are typically between 5 20 years.
According to the epa you can expect net annual savings of just under 50 cents per square foot of roof.
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Upgrade from r to r h ft f btu details of comparison.
Insulation savings calculator use this insulation savings calculator to measure the financial impact of increasing your insulation performance.
If the roof is not being replaced for other reasons it is typically not cost effective to add insulation.
Knowing the cost of energy and the cost of the insulation upgrade you can calculate the rate of return on your investment in insulation.
Net savings ft per year cooling savings ft per year heating savings heating penalty if negative ft per year insulation in black roof to yield same annual energy savings.
Knowing the r values before and after an insulation upgrade and the average temperature difference across the insulation you can calculate the amount that the insulation upgrade reduces heat flow.
It is not easy to calculate.