The Science of Experience



How Long Will It Take For Your Spray Foam Insulation Upgrade to Pay You Back?

Posted by Emillie Lee

Jan 23, 2017 9:00:00 AM

money and time.jpeg

Insulation's job is to prevent cold air from coming into your home and warm air from leaking out. In the hot summer months, it does the opposite. It makes sense then, that adding more insulation to your home will decrease your energy bills by better protecting your home from heat exchange. But just how long will it be before your energy savings make up for the initial cost of the insulation?

Whether you're using polyurethane spray foam insulation or fiberglass, follow these steps to calculate your payback time -- the amount of time after which your energy savings will pay for the cost of your insulation.

Start by gathering the following information:

  • C(i) = Cost of insulation in dollars per square foot.
  • C(e) = Cost of home energy in dollars per Btu
  • E = How efficient your heating system is, expressed as a decimal. For example, a furnace that burns 88% of fuel would have a value of E = 0.88.
  • HDD = The number of days per year that you run your heating system. You can usually obtain an average for this value from your utility company.
  • R(1) = R-value of the existing insulation in your home.
  • R(2) = R-value of all of the insulation in your home, after the new insulation has been added.

Then, plug your values into this formula:

Payback time (in years) = [ C(i) x R(1) x R(2) ] / [ C(e) x {R(2) - R(1)} x HDD x 24]

Remember that the value you obtain is an estimate. Temperature fluctuations, your home structure, and the type of insulation you choose may all slightly impact the real time it takes you to break even.

Polyurethane spray foam insulation is a great way to save energy. Contact NCFI Polyurethanesto learn more about this alternative to fiberglass.


Topics: Energy Efficiency, Low Costs, NCFI