A woman in North Canton called me last November because her upstairs would not get above sixty four degrees. She had already replaced the thermostat and had somebody quote her a bigger furnace. The furnace was fine. Her attic hatch was a sheet of plywood with a two inch gap around it, and the bathroom fan vented into the attic, and the rim joist in the basement was open to the outside along most of the north wall.
That is what an energy audit finds. Not the thing you were worried about. The three things you were not.
What actually happens during one
It takes two to three hours and most of it is not dramatic to watch.
I fit a blower door into your front doorway. It is a fabric panel with a calibrated fan in it, and it pulls air out of the house until the inside is at a set pressure below the outside. The fan tells me how much air it had to move to hold that pressure, and that number is how leaky your house is. There is a target for a house your size and age, and most Canton houses miss it badly.
While the house is depressurised, every gap becomes a small draught, and that is when the infrared camera earns its keep. Cold air pouring in shows up on the screen as blue rivers running down a wall. You can stand there and watch your money leave, which is more persuasive than anything I could say.
Then I go into the attic and measure insulation depth in several places, because it is never uniform, and look at whether anybody has vented a bathroom fan up there. Somebody usually has.
The last part is ducts. If your supply ducts run through an unconditioned attic or crawlspace and they leak, you are paying to heat a space nobody sits in.
Whether you need one
Probably yes if the house was built before 1970 and nobody has done air sealing since. Probably yes if one room is always cold and everyone has blamed the furnace. Probably yes if you are about to spend four or five thousand dollars on a new heating system, because sizing a furnace for a leaky house means buying a bigger one than you would otherwise need.
Probably not if the house is fifteen years old, tight, and comfortable. In that case you are paying me 325 dollars to tell you it is fine, and while some people want that, I would rather say so up front.
The report you get back is a ranked list with costs beside it. Attic air sealing sits at the top most of the time, and it is boring, and it usually pays for itself inside three winters. Rim joist sealing is often second. New windows are almost never in the top three, which surprises people, because windows are the thing everyone is selling.