The total renovation to date has cost $300,000 or $83 per ft2. This amount includes upgrades that were not done purely for energy efficiency, including total electrical and plumbing replacement, the finishing of the attic and basement space, the addition of two new full baths and the renovation of the existing baths and kitchen.

It also included the cost of a new roof and new exterior siding. Separating the cost of the windows, the insulation, and the heating system, the additional cost to provide energy improvements alone came to $75,000.

A natural gas price of $1.50 per therm financed over a 30-year mortgage with an interest rate of 7%, results in a negative cash flow per year of $827. However, reduce the interest rate to 4% and it is cash flow neutral. Furthermore, imagine the cost of gas increasing over the $1.50 per therm rate, and the improvements are easily justified.

The experience allowed my company to understand what parts of this renovation were the most costly and how savings might be achieved while still achieving the same impact on the energy performance.