I had two energy audits done on my home. One contractor did the audit for free; the other offered a free audit and a more extensive test for $250. I went for the more extensive test.

Homeowners are told that there is no obligation to make any of the changes recommended in an audit, but those who get work done can qualify for low- or no-cost loans, and for state rebates based on how much energy they will save by making the recommended changes.

Mr. Sheehan said that contractors who are certified and accredited by the state of New Jersey offer free or cheap audits because they know they can pitch homeowners to do the work. Those contractors also become part of a marketing cooperative that provides marketing materials and rebates for some marketing costs.

On New Jersey’s energy website, njcleanenergy.com, I searched for local contractors, choosing five within a 10-mile radius of my house. Two never got back to me; another left a strange voice mail message. The other two responded to my emails right away, and I scheduled audits with both.

The audit process itself was relatively simple.

The contractors asked similar questions about the house, whether I had allergies or asthma and where I felt variations in temperature. They also asked for a copy of my utility bills to see how much energy I was using, as the amount helps determine how much of a rebate I could get from New Jersey. Contractors usually want a full year of bills, but since I had been in the house only since July, they looked at what I had available.

Then they poked around and performed a few basic tests to see where I was losing heated or cooled air. The tests included using a thermal camera to document changes in temperature; identifying which parts of the house bumped out from the main structure; and going into the crawl space, attic and basement to see what kind of insulation (if any) was there. Each audit took about three hours.