What a real assessment includes
The Department of Energy's consumer guide to home energy assessments describes two core tests. A blower door, a fan mounted in an exterior doorway, depressurizes the house so outside air pulls in through gaps. Ask for a calibrated blower door, one connected to a pressure gauge called a manometer, because that gives an exact measurement of how leaky the house is. An infrared camera scan, done during the blower door test, shows leaks as dark streaks. The assessor may also test duct leakage with a duct blower, look at the furnace or boiler, check for gas leaks and check ventilation.
Not every "assessment" includes those tests, so ask before you book. The Community Net-Zero Education Project, a Philadelphia nonprofit, notes that PECO's standard $49 assessment is a one- to two-hour walk-through without a blower door test, while homes heated with electricity (including heat pumps) can get a more in-depth $99 version that adds a blower door and thermal imaging. PECO's own flyer for the $49 assessment says it's for PECO electric customers, one per home per year, with a custom report and up to $125 in free energy-saving products. Private assessments run roughly $250 to $600 or more, according to DOE, and many contractors discount the fee if you hire them for the work.
Why it can change what you buy
Insulation slows heat moving through a surface, but it doesn't stop air. DOE's air sealing guide compares insulation to a sweater and air sealing to a windbreaker. If the blower door shows big leaks between the living space and the attic, those get sealed before more insulation goes on top. DOE's insulation guide lists a history of ice dams as a sign of serious air leaks.
Windows are the other big question. DOE's weatherization guide for homeowners puts windows at 25 to 30 percent of home heating and cooling energy use, but it also says windows in good condition don't have to be replaced. Caulk, weatherstripping, storm windows, window coverings or solar film come first. Its priority list puts air sealing, attic insulation, sealing and insulating the basement rim joist and adding storm windows at high priority, and new windows at low priority. The same guide lists window replacement at about $150 to $1,500 per window, so the gap between "seal and add storms" and "replace twelve windows" can be large.
Signs an assessment is worth it before windows or insulation:
- Some rooms are much colder or hotter than others, or you feel drafts away from the windows.
- You're getting quotes for more than a few windows and they're still sound, just drafty.
- The attic looks thin or uneven, or you've had ice dams or attic moisture.
- Bills seem high for the size of the house and you don't know why.
If a window is cracked, rotted or won't close, fix it now. That's a repair, not an efficiency decision.
Fix leaks first, and don't skip the safety checks
DOE's Weatherization Assistance Program lists repairing minor roof and wall leaks before attic or wall insulation, along with combustion appliance safety testing, among its standard measures. Tightening a house changes how much air a gas furnace, boiler, water heater or fireplace can draw. DOE's air sealing guide warns that without enough air these appliances can release carbon monoxide, which is why ventilation and combustion testing belong in the plan. Ask who will do that testing before and after air sealing, and make sure your CO alarms work. Don't try to run pressure or combustion tests yourself.
Before the visit and what to ask
DOE suggests having recent energy bills ready and a list of problems you've noticed, like condensation and drafty or uncomfortable rooms. Then ask:
- Is a calibrated blower door test included, and will I get the leakage number?
- Will you scan with an infrared camera while the blower door runs?
- Are you certified, and do you also sell the upgrades you recommend?
- Can I take the report to other contractors for quotes?
- Will you test the heating system and water heater for safe venting?
One thing has changed: the federal tax credit that covered part of an energy audit and of window and insulation upgrades ended after 2025, according to the IRS. Older articles and some contractor pitches still mention it, so don't count it in your budget for 2026 work. Utility programs and income-qualified weatherization help are the places to check now.