Home Energy Audits: What a Professional Actually Checks

A genuine professional home energy audit is a diagnostic process, not a walkthrough that ends in a sales pitch for attic insulation. If an "audit" is free and immediately becomes a quote for one specific product, that's a marketing visit wearing an audit's name — a real audit is a paid, structured inspection with a written report as the deliverable.

What's actually included

1. A blower door test — a calibrated fan temporarily mounted in an exterior door depressurizes the house to measure actual air leakage, giving a real number (air changes per hour) rather than a visual guess.
2. Infrared thermal imaging — used to visualize where insulation is missing or thin, typically done during or after the blower door test while the pressure differential makes leaks more visible on camera.
3. Combustion safety testing — checking gas appliances (furnace, water heater) for backdrafting or unsafe combustion byproducts, especially important once a home is made tighter through other efficiency work.
4. Insulation assessment — attic, walls, and rim joists, checked against recommended R-values for your climate zone, not just a visual "looks fine" check.
5. Ductwork inspection — checking for leaks in forced-air duct systems, a common and often underestimated source of efficiency loss.

What it typically costs

Professional audits with the full blower-door-and-infrared process commonly range from $250–$700, depending on home size and region — some utilities subsidize or fully cover audits as part of efficiency programs, which is worth checking before paying out of pocket. A free "audit" from a company primarily selling one product (insulation, windows, or HVAC) is a different, more limited service, even when it uses similar language.

How to read the results

A thorough audit report ranks recommendations by cost-effectiveness — air sealing is very often the highest-return recommendation, ahead of most insulation or equipment upgrades, because leaks are relatively cheap to fix and directly reduce both heating and cooling loss. Be cautious of a report that recommends only the most expensive interventions (full insulation replacement, new HVAC) without addressing cheaper air-sealing opportunities first.

| Common recommendation | Typical relative cost | Typical relative impact | |---|---|---| | Air sealing (caulk, weatherstripping, sealing penetrations) | Low | Often high | | Attic insulation top-up | Moderate | Moderate–high, if currently under-insulated | | Duct sealing | Moderate | Moderate, if leaks are significant | | Window replacement | High | Often lower than expected relative to cost |

FAQ

Is a blower door test safe for my house? Yes, it's a standard, non-invasive diagnostic tool used broadly in the building performance industry — it doesn't damage the home, and the pressure differential is controlled and temporary.

How long does a full audit take? Typically 2–4 hours for an average single-family home, depending on size and complexity.

Should I get an audit before or after getting solar quotes? Generally before — reducing your usage through efficiency work first means any solar system you install afterward can be sized smaller (and cheaper) while still covering your usage, discussed further in our home solar guide.

Found an error? See our Corrections Policy.