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What does this tool do?

Durability Doctor helps you compare the durability and annualized cost of the alternative materials for a home's exterior building elements-- windows, garage doors, roofing, and siding.

How do I use Durability Doctor?

If you have never used Durability Doctor before, please start by Signing In, so that you may save your information. You can use Durability Doctor without logging in, but your entered information will not be available from session to session.

After you have logged-in, enter information about the physical details of your house, including a mortgage interest rate. Review and make changes to the calculated siding and roofing dimensions of your home. Next, select materials used on the house using the drop-down boxes. All this information is used to perform the durability analysis. Durability Doctor displays several analyses of the house-- Your Costs, i.e., of your existing building materials, as well as Lowest Initial Cost, Most Durable, and Lowest Annualized Cost, when comparing all building materials.  Each view shows the name of the material, durability, installed cost, annualized installed cost, annualized maintenance cost and the total annualized cost.

Inspect the results to see the advantage of selecting more durable building materials.   Given your project performance requirements, though durable products may cost more initially, their longer durability can pay off in the long run in terms of lower annualized costs. The material with the lowest annualized cost represents a balance when considering durability, installed cost, and maintenance cost.


The Installed Cost is an estimate of the labor cost plus the cost of the materials to have a contractor install the material on your home this year.

The Annualized Installed Cost is equivalent to the yearly payment of principal and interest if you finance the Installed Cost of the material, over its expected service life (durability).

The Annualized Maintenance Cost is equivalent to the yearly savings required in order to meet required maintenance tasks at a future date.

The Total Annualized Cost is the sum of both the Annualized Installed Cost and the Annualized Maintenance Cost.

Origin of Data

The normal service-life (durability) values used here are based on information gathered from industry associations, materials manufacturers, contractors, warrantees, Whitestone Research, and the National Association of Home Builders Research Center.