Most people start looking into this after a utility bill comes in higher than it should have, or because one bedroom stays cold no matter where the thermostat is set.
A home energy audit puts a number on that problem. A certified auditor goes through the house with a blower door and an infrared camera, then compares what they find against the home’s own utility history and against a standardized reference home. The result is a list of fixes ranked by potential savings.
There’s a resale angle too. Lawrence Berkeley National Laboratory found that home sale prices rose 0.5 percent for every one-point gain on the Department of Energy’s ten-point Home Energy Score scale, based on a 2022 analysis of more than 25,000 rated homes.
What Is a Home Energy Audit
An auditor walks the property, tests how tight the building envelope is, and inspects the equipment that heats, cools and runs the house. The goal is to find where energy gets wasted and how much of it.
People tend to lump this in with a home inspection. The two overlap a little, but an inspection checks safety and condition. An audit goes after something narrower, which is locating specific, measurable sources of energy waste and ranking the fixes by savings.
Most homeowners meet the whole-house energy audit under a different name. Utility programs and state energy offices often call it a home energy assessment or a home energy evaluation, and so do a lot of contractors. It’s the same visit either way.
The walls, attic, windows and doors all get looked at, along with the heating, cooling and water heating equipment. Major appliances go on the list with their typical energy draw.
What comes out of it is a document the homeowner can act on directly, rather than a general impression of the house.
Home Energy Audit vs Home Inspection
The two get confused constantly, which is understandable. Both send a trained person through the house with a checklist.
That’s about where the overlap ends. Safety and condition belong to the inspection, while the audit is entirely about energy performance.
| Aspect | Home Inspection | Home Energy Audit |
|---|---|---|
| Main focus | Safety, code compliance, structural condition | Energy waste and efficiency performance |
| Core tools | Visual checklist, moisture meter | Blower door test, infrared camera |
| Typical output | Pass or fail condition report | Ranked list of efficiency upgrades |
| Common timing | At the time of sale | Any time, often before upgrades or rebates |
An inspector might note a drafty window or glance at the attic insulation. Without a blower door reading, though, that stays an impression and never becomes a number.
How a Home Energy Audit Works
The visit follows a fairly consistent order no matter who performs it, because auditors collect the data first and interpret it afterward.
- The auditor goes through twelve months of utility bills to set a baseline for how much energy the home actually uses.
- A visual walkthrough of the interior and exterior picks up obvious gaps, moisture and the age of the equipment.
- Diagnostic testing comes next. The blower door, infrared camera and duct testing equipment measure what the eye can’t see.
- Major appliances and HVAC equipment get logged with their approximate age and condition.
- Everything goes into a written report, with recommendations ranked by cost-effectiveness.
A finished basement or several HVAC zones will stretch the visit, but the order stays the same.
What a Home Energy Audit Checks
The audit mixes hands-on testing with a room-by-room review, and the final report draws on both.
Diagnostic tests and equipment used
Air leakage gets measured with a calibrated blower door test. A fan mounts in an exterior doorway and depressurizes the house, so the auditor can put a number on how much outside air is getting in.
The thermal imaging camera follows the same test. A depressurized house pulls outside air through every gap, and the camera shows each one as a temperature difference.
For a sense of scale, a typical existing home leaks at roughly 15 air changes per hour at that test pressure, according to Energy Vanguard. (The raw reading is CFM50 before it’s converted to ACH50.) Many current building codes require 3 to 5 ACH50 for new construction, so the typical existing home sits well above that.
A duct blaster test checks the HVAC ducts for leakage, and gas appliances get a combustion safety check. Auditors may also take moisture readings in a basement or crawl space.
Building areas and systems inspected
The envelope gets the closest look, since that’s where most of the energy is lost. Auditors record insulation levels in the attic and wall cavities (and sometimes at the rim joist), then measure them against the R-value. Windows and doors get checked for seal condition and glazing type, and any gaps around plumbing or wiring penetrations get noted.
On the equipment side, the HVAC system is assessed for age, filter condition and airflow balance. The water heater gets its age, efficiency rating and any venting issues written down.
Nothing gets fixed during the visit itself. The auditor measures and documents, and that’s where the job ends.
What a Home Energy Audit Report Includes
The report is what you’re actually paying for. It’s mostly a list of findings rather than a narrative, and each one traces back to something the auditor measured on site.
Expect a baseline summary comparing the home’s energy use against similar homes, plus the blower door and duct test results (as ACH50 and a duct leakage percentage). The main part is the prioritized list of recommended upgrades, ordered by cost-effectiveness. Any safety flags, such as backdrafting or a carbon monoxide risk, get noted too.
Windows usually show up by their U-value rating, and a lower number means less heat is passing through the glass.
Cheap fixes nearly always lead the list, and air sealing around obvious penetrations tends to sit near the top. Bigger-ticket items like insulation or HVAC replacement come later.
Who Is Qualified to Perform a Home Energy Audit
A clipboard and a flashlight don’t make someone a qualified auditor.
Two credentialing paths dominate the U.S. market, and both require a standardized exam plus supervised field hours. Certified auditors follow standardized testing procedures rather than an informal walkthrough, and some rebate and weatherization programs accept only a certified auditor’s report. If a rebate is the goal, check the credential before booking anyone.
| Credential | Issuing Body | What It Covers |
|---|---|---|
| HERS Rater | RESNET | Full diagnostic testing and HERS Index scoring |
| Home Energy Professional Energy Auditor | BPI | Building science, combustion safety, retrofit planning |
| Building Energy Assessment Professional | ASHRAE | Commercial and technical energy assessment |
There’s a more recent wrinkle as well. Since 2024, IRS and Treasury guidance has required auditors claiming the federal home-audit tax credit to list a business EIN (or other taxpayer identifying number) and attest to their certification directly in the written report.
For a homeowner, that makes a credential easy to verify, so nobody has to take a business card at face value.
How Much a Home Energy Audit Costs
Price depends mostly on the size of the home and where it is, plus how much diagnostic testing gets included. A basic walkthrough costs less than a full test-out with a blower door and duct testing.
A professional home energy audit in the U.S. typically runs $200 to $700 (SaveOnEnergy, 2025). Set against that, acting on typical audit recommendations can cut energy bills by 5 to 30 percent (U.S. Department of Energy). That’s a wide range, and where a given house ends up depends on what the auditor finds and how much of it gets fixed.
How long a visit takes
The on-site visit usually runs 30 minutes to 3 hours, depending on home size and testing depth (NYSERDA). Smaller homes with a simple heating system tend to land on the short end of that range.
A bigger house or multiple HVAC systems can push the visit toward the three-hour mark. Add-on tests like a duct blaster or a combustion safety check do the same.
Professional Audit vs DIY Audit vs Virtual Audit
DIY and virtual audits get you part of the way, but they aren’t interchangeable with a professional one. Only the professional version produces numbers a rebate program will usually accept.
| Aspect | Professional Audit | DIY Audit | Virtual Audit |
|---|---|---|---|
| Tools used | Blower door, infrared camera, duct blaster | Flashlight, incense stick, checklist | Homeowner photos or video call |
| Typical cost | Paid, sometimes rebate-eligible | Free | Free to low-cost |
| Accuracy | Measured, numeric results | Visual, subjective | Visual, remotely reviewed |
| Qualifies for rebates | Usually, if auditor is certified | Rarely | Sometimes |
Massachusetts handles this at scale through Mass Save. The program is utility-funded, and it sends a certified technician to eligible residents’ homes for a full blower door and infrared assessment at no direct cost.
A DIY walkthrough with a flashlight and an incense stick will still catch the obvious drafts around doors and outlets. That’s about as far as it goes. With no blower door, there’s no number to compare against a code requirement or a before-and-after retrofit result.
For a rebate or a tax program, it has to be a professional audit. On a tight budget and mostly curious, a DIY walkthrough does the job, and a virtual audit is fine as a quick second opinion before you hire a contractor.
Is a Home Energy Audit Worth It
The audit itself doesn’t save a dollar. Acting on what it finds does.
There’s a resale angle too. Homes with lower HERS Index scores sell for 3 to 5 percent more than comparable homes with higher scores, according to a Freddie Mac study of the resale market.
The practical upside is mostly about bills and comfort. Utility costs come down once the flagged fixes get made, cold rooms and drafts fade, and safety problems like backdrafting get caught before they turn dangerous. The documentation can also support a higher asking price.
The downsides are just as plain. The fee is upfront, and nothing guarantees a dollar-for-dollar payback. In busy regions, getting a certified auditor on the calendar can take weeks. And the savings depend entirely on whether anyone follows through on the recommendations.
A homeowner who reads the report and does nothing with it ends up with a document, not a lower bill. For an older house with a history of high bills, I’d say it’s an easy call. For a house that’s already been tuned up, it’s a harder one to justify.
Incentives and Rebates for a Home Energy Audit
A handful of programs offset either the audit itself or the upgrades it recommends, and they’re funded in different ways.
The Weatherization Assistance Program covers the full cost of qualifying upgrades for income-eligible households. Those households save $372 or more a year on utility bills on average, according to the U.S. Department of Energy. The help comes through state and local weatherization agencies rather than as a lump-sum check.
Low-income households can reach this weatherization rebate path through their state energy office instead of paying out of pocket.
The Home Efficiency Rebates program (HOMES), funded through the Inflation Reduction Act, works on a different model. Homeowners can get up to $2,000 for a whole-house retrofit that cuts energy use 20 to 34 percent, or up to $4,000 for cuts of 35 percent or more. Low- and moderate-income households qualify for double those amounts, up to $4,000 and $8,000, per DOE program guidance.
NYSERDA is among the state energy offices rolling out this rebate in New York. It layers on top of programs like EmPower+, which already require a qualifying audit first.
The federal Energy Efficient Home Improvement Credit (25C) used to cover up to $150 of an audit’s cost, capped at 30 percent, for work completed through the end of 2025. It expired for anything placed in service after December 31, 2025.
Insulation work the audit turns up may still qualify for a state insulation tax credit or a utility rebate, even where the federal version has lapsed.
How to Prepare for a Home Energy Audit
Most of the prep takes fifteen minutes the night before, and it shortens the visit and sharpens the report.
- Pull twelve months of utility bills, or set up online account access so the auditor can pull them directly.
- Write down the specific comfort complaints, like the cold bedroom or the room that never cools down.
- Clear access to the attic hatch and any HVAC closets, plus the crawl space if there is one.
- If you know the age of the water heater and major appliances, jot that down too.
Don’t run the bathroom or kitchen exhaust fans right before the visit, and don’t leave windows or exterior doors propped open. Skip lighting the wood stove or fireplace as well. Any of that throws off the blower door reading before the fan even starts.
What Happens After a Home Energy Audit
The report is where the work starts. Most homeowners go through the prioritized list a piece at a time instead of tackling every recommendation at once.
In my view the cheap, fast items should go first, things like caulking and weatherstripping. Anything above a few hundred dollars deserves two or three contractor quotes. Whatever upgrades are left should get matched to any rebate or program that still needs proof of the audit.
Bigger jobs like insulation or HVAC replacement tend to depend on contractor availability as much as budget, so schedule around that.
Some programs also allow a follow-up blower door test once the work is done, which confirms the leakage rate actually dropped. That before-and-after number is the only real proof the upgrades did what they were sold to do.
When a Home Energy Audit Does Not Apply
An audit isn’t automatically useful just because a house exists.
New construction usually doesn’t need one. Homes built to current energy code already meet a baseline envelope and HVAC performance level, so a full audit adds little beyond what the code inspection already confirmed.
Renters are stuck without the owner’s sign-off, since a tenant can’t authorize a blower door test or any invasive testing on a unit they don’t own.
A home that’s already been HERS-rated or recently audited is a poor candidate too. Repeating the full diagnostic package within a year or two rarely turns up anything new.
Then there’s intent. The report only pays off once its recommendations get implemented, so paying for one with no follow-up plan wastes the fee.
Manufactured and mobile homes typically need a specialized assessment protocol rather than the standard residential audit process.
None of this means the energy problems go away. It means a standard audit is the wrong tool, or the wrong moment, for dealing with them.
FAQ on What Is A Home Energy Audit
Does a home energy audit give the house a numeric score?
Sometimes. A RESNET-certified rater can calculate a HERS Index score during the same visit, comparing the home to a reference house of the same size and shape built to the 2006 IECC energy code. A basic walkthrough gets you a report but no index number.
Is a home energy audit ever free?
Many electric and gas utilities fund no-cost or heavily subsidized audits for ratepayers, and income-qualified households can get one through the Weatherization Assistance Program. Outside those programs, a full diagnostic audit with a blower door and infrared scan usually carries a fee.
Does getting an audit help when selling a house?
Cities like Portland and Berkeley require a documented energy score at listing, so buyers see proof of efficiency before they bid. Elsewhere it stays optional. Even then, the report gives a seller concrete numbers to back up an asking price.
How often should a home get audited?
There’s no fixed schedule, and no agency publishes one. Most homeowners get one once, then again after a major renovation or a new HVAC system, or when utility bills jump for no obvious reason.
What commonly goes wrong during a home energy audit?
A running dishwasher or an open window during testing can skew the blower door reading and understate the leakage rate, and so can closed-off rooms. A rushed walkthrough that skips the attic or crawl space is the other usual problem, since it misses the biggest sources of heat loss.
Can renters get a home energy audit done?
Only with the property owner’s written consent, since the auditor needs access to the attic and HVAC closets, and sometimes the utility account itself. Even then, the landlord decides which recommended upgrades actually get done, not the tenant living there.
What Does a Home Energy Audit Recommend Most Often?
Air sealing and insulation upgrades come up more than anything else, ahead of HVAC replacement, water heater changes and duct repair. That’s based on findings compiled during the visit.
More than 90 percent of certified auditors say they recommend both fixes on nearly every visit, according to a Resources for the Future survey of home energy professionals.
Sealing a house below 5 ACH50 triggers a different requirement under Section R303.4 of the International Residential Code, which calls for mechanical ventilation once a home reaches that level of tightness.
A tightly sealed house holds warmth more efficiently but needs a fan or heat-recovery ventilator to manage moisture and indoor air quality past that threshold.
The natural next step is understanding home insulation itself, since that single upgrade carries the largest share of audit-driven recommendations nationwide.
