I found extraordinary savings to be achieved in this 1400 sf one-story home. Savings through my labor and placement of materials include reduction of conduction/ convection heat loss cost, of about $950 per year. $550 per year of this is due to closure of an extraordinary distribution of attic floor pits. $400 per year is due to the addition of insulation, from R4 to R38. There are further but much-smaller and indeterminate savings, from reduced house air infiltration. The dollar numbers, at $2 per therm, are large vs actual gas bills. They believably correspond to a modest one-third reduction of natural gas consumption, with a 1.6 ton per year reduction of CO2 conversion.
I have complained against the no-bid presented with the "confidential" home performance test. At this Picasa Web Albums page, I disclose the report scanned for me, by the customer.
The customer paid $209 for perhaps two sets of blower door and duct blaster tests in a part-day of service where ducts in the attic were gooped, and were wrapped with 24" x 48" patches of unfaced R11 batt fiberglass. A $35 rebate is offered for just one blower door test per residence, I thought. Two seem to have been claimed, although the report does not have a second set of numbers.
I did very thorough sealing of the attic floor, as reported at my web site.