Insulated garage door energy savings calculator
This only applies to a garage you heat. Pick the door, your climate, and your fuel to see a savings range.
Heat loss = door area x heating degree days x 24 x (1/R old - 1/R new). Degree days (base 65 F) come from Engineering ToolBox city data. R-value ranges are from door maker tables. Energy prices are U.S. residential averages from the EIA (electricity 17.3 cents per kWh, natural gas $15.34 per Mcf, about $1.48 per therm).
How this calculator works
Heat loss through a door equals its area times the heating degree days times 24 hours times the difference between the old and new heat flow per square foot (1 divided by the R-value). That number of BTUs is turned into dollars using the U.S. average residential price of natural gas or electricity and the efficiency of your heat source.
Savings only apply to a garage that is actively heated. Non-insulated steel is treated as R-1, and the other R-values are published ranges from door makers, so the result is shown as a range.
Frequently asked questions
Will an insulated garage door lower my heating bill?
Only if the garage is actively heated. If it is not, the door does not change your heating costs. If it is heated like the rest of the house, savings can run from tens to a few hundred dollars a year depending on climate and door size.
What R-value should a garage door have?
Door makers suggest at least R-10 for an attached garage, R-12 for a heated one around 46 to 50 F, and R-16 for a workshop or gym. These are manufacturer suggestions, not code requirements.
Is polyurethane or polystyrene better?
Polyurethane foam usually has the higher R-value (about R-13 to R-18 in maker tables, versus R-6 to R-9 for polystyrene). It also costs more.
Related calculators
Last updated October 2026. Reviewed by the Fix or Hire editorial team. Estimates only, not a quote.