I had an energy audit done on my house three years ago. The auditor found that my attic insulation was roughly half of what it should be, air was leaking around every recessed light in the ceiling, and the ductwork in the crawl space had separated at two joints. I was essentially heating and cooling the outdoors. The audit cost me $350. The fixes cost about $2,800. My energy bills dropped by $140 a month. That’s a payback of less than two years on a problem I didn’t even know I had.
Most homeowners have no idea where their energy goes. They see a high utility bill and assume that’s just what it costs. A professional energy audit tells you exactly where you’re wasting money and, more importantly, which fixes give you the best return. But not all audits are created equal, and not all auditors give you the full picture.
These 15 questions help you get the most out of your audit and turn the results into real savings.
Before You Contact an Energy Auditor
A bit of preparation makes the audit more thorough and the results more useful:
- Gather 12 months of utility bills. Both electricity and gas (or propane/oil). The auditor needs to see your seasonal usage patterns to identify where the biggest losses are. Many utilities provide this data online.
- Note your biggest comfort complaints. Rooms that are always too hot or cold, drafty areas near windows or doors, humidity problems, musty smells. These clues help the auditor focus the inspection.
- Know the basics about your home. Year built, square footage, insulation type (if you know it), HVAC system age, and when the windows and doors were last replaced. Don’t worry if you don’t have every answer. That’s what the audit is for.
- Make a list of recent improvements. If you’ve added insulation, replaced windows, or upgraded your HVAC in the last few years, tell the auditor so they don’t waste time evaluating something that’s already been addressed.
- Check for utility-sponsored audit programs. Many utilities offer free or subsidized energy audits. Some even provide rebates for implementing the recommended fixes. Call your utility before paying full price.
What to Mention or Send Beforehand
Share these details when you schedule the audit:
- Your utility bills. Email or provide access to 12 months of data. Some auditors can pull this directly from your utility account with your authorization.
- Your home’s age and construction type. This tells the auditor what to expect in terms of insulation standards, building practices, and common issues for that era of construction.
- Known problem areas. That cold bedroom over the garage, the drafty front door, the basement that’s always damp. Point the auditor where the problems are.
- Your budget and priorities. If you’re willing to spend $5,000 on improvements, the auditor can prioritize recommendations accordingly. If you’re looking for quick wins under $500, say so.
- Access requirements. Let the auditor know about attic hatches, crawl space access points, and any areas that might be difficult to reach.
What the Audit Includes
1. What does your energy audit actually include, and what tests will you perform?
A real energy audit goes way beyond a guy walking around your house with a clipboard. A comprehensive audit should include a blower door test (to measure air leakage), infrared thermal imaging (to find insulation gaps and thermal bypasses), duct leakage testing, combustion safety testing on gas appliances, and a detailed inspection of insulation, windows, and HVAC equipment.
If an auditor isn’t doing a blower door test and thermal imaging, you’re getting a walkthrough, not an audit. That’s like a doctor taking your temperature and calling it a physical exam.
2. Are you certified, and by what organization?
Look for BPI (Building Performance Institute) certification or RESNET HERS Rater certification. These are the two main credentials for residential energy auditors, and they require hands-on training, exams, and quality assurance checks.
An uncertified auditor isn’t necessarily incompetent, but there’s no accountability if their recommendations are wrong. Certification also matters if you want to qualify for utility rebates or government incentive programs, because many of those programs require a certified auditor.
3. What equipment do you bring, and can I see the results in real time?
A well-equipped auditor arrives with a blower door (a calibrated fan that fits in your door frame), an infrared camera, a duct blaster for testing duct leakage, a combustion analyzer, and a moisture meter. Asking to see the infrared images and blower door numbers in real time is completely reasonable. In fact, a good auditor will show you.
When you watch the blower door test and see the infrared camera light up with blue spots around your windows, you’ll understand exactly where the problems are in a way no written report can communicate. Keeping your own thermal leak detector on hand lets you spot-check problem areas after the audit.
Understanding the Results
4. What is my home’s air leakage rate, and how does it compare to the recommended standard?
The blower door test measures air leakage in “air changes per hour at 50 Pascals” (ACH50). A typical older home might test at 10-15 ACH50. The target for an energy-efficient home is usually 3-5 ACH50, depending on your climate zone.
This single number tells you how leaky your home is. If you’re at 12 ACH50 and the target is 5, you’re losing more than half your conditioned air through cracks, gaps, and holes. The auditor should explain where the biggest leaks are and what it would cost to seal them.
5. Where are the biggest energy losses in my home?
Most homes lose energy through the same culprits: air leakage (gaps around windows, doors, plumbing penetrations, and electrical outlets), inadequate insulation (especially in the attic), leaky ductwork, old HVAC equipment, and inefficient windows.
The audit should rank these losses from biggest to smallest so you know where to spend your money first. A good auditor gives you a prioritized list, not just a laundry list of everything that’s wrong.
6. What are the top three fixes that will give me the best return on investment?
This is the money question. Literally. Air sealing the attic and adding insulation often has the highest ROI of any home improvement. Sealing ductwork is usually second. HVAC upgrades and window replacement are important but typically more expensive per dollar saved.
Ask the auditor to rank improvements by payback period. “Seal the attic for $1,200 and save $60/month” is a 20-month payback. “Replace all windows for $18,000 and save $40/month” is a 37-year payback. Very different return profiles.
Costs and Implementation
7. How much does the audit cost, and are there utility or government rebates?
Professional energy audits range from $200 to $600 for a standard home. Some are more for very large homes or if specialized testing (like a HERS rating) is included.
Many utilities offer free or discounted audits as part of their energy efficiency programs. Some state programs reimburse the audit cost if you implement a certain number of recommendations. Ask your utility first, and ask the auditor whether they participate in any rebate programs.
8. Will you provide a written report with prioritized recommendations and estimated costs?
An audit without a written report is just a conversation you’ll forget half of by next week. The report should include test results (blower door number, duct leakage, insulation R-values), prioritized recommendations ranked by estimated savings and cost, estimated annual energy savings in dollars for each improvement, and any safety concerns found during the inspection.
Some auditors also provide an energy model showing your home’s current performance versus projected performance after improvements. That level of detail makes it easy to justify the spending.
9. Can you estimate the cost and payback period for each recommended improvement?
Estimated costs and payback periods turn an audit from a wish list into an action plan. You might not be able to do everything at once, and that’s fine. But knowing that air sealing pays for itself in one year while window replacement takes 15 years helps you decide where to start.
Ask the auditor to be specific. “Improve insulation” is vague. “Add R-30 blown cellulose to the attic, approximately 800 square feet, estimated cost $2,000 to $2,500, estimated annual savings $720” is actionable.
Safety and Health Concerns
10. Will you test for combustion safety and carbon monoxide risks?
Any gas-burning appliance (furnace, water heater, stove, fireplace) can produce carbon monoxide if it’s not drafting properly. Tightening up a home’s air envelope without checking combustion safety can actually make CO problems worse by reducing the fresh air that combustion appliances need.
A BPI-certified auditor will test for this as standard practice. They check the draft on your furnace and water heater, measure CO levels in the flue gases, and verify that tightening the home won’t create a backdrafting hazard.
11. Should I be concerned about moisture, mold, or indoor air quality?
Air sealing and insulation changes affect moisture dynamics in your home. Done correctly, they improve comfort and reduce mold risk. Done incorrectly, they can trap moisture and create new problems.
The auditor should assess current moisture conditions (using a moisture meter on suspect areas) and explain how proposed improvements will affect moisture. If there’s existing mold or moisture damage, that needs to be addressed before insulation or air sealing work begins.
Working with Contractors
12. Do you also do the remediation work, or do you only audit?
Some auditors are independent and don’t perform the actual improvements. Others work for companies that do both audits and upgrades. There are pros and cons to each approach.
An independent auditor has no financial incentive to recommend unnecessary work. An audit-and-upgrade company can offer a seamless process but might lean toward recommending services they provide. If the same company audits and fixes, consider getting a second opinion on the bigger-ticket recommendations.
13. Can you help me find qualified contractors for the recommended work?
A good auditor has relationships with insulation contractors, HVAC companies, and air sealing specialists in your area. They can point you toward contractors who do quality work, and they know what a fair price looks like.
Ask whether the auditor will review contractor bids for you or verify that the work was done correctly after completion. Some auditors offer a post-improvement verification test (another blower door test) to confirm that air sealing actually moved the needle.
14. Are there financing programs or rebates available for the recommended improvements?
Many states and utilities offer rebates for energy efficiency improvements, especially insulation, air sealing, and HVAC upgrades. The Inflation Reduction Act also provides tax credits (up to $1,200 per year) for qualifying home energy improvements.
Your auditor should know about these programs and help you navigate the paperwork. Some rebate programs require a pre-approval or a specific audit format before you start work, so ask about this before you begin.
15. Should I get a follow-up audit after the improvements are done?
Absolutely. A post-improvement blower door test verifies that air sealing actually worked and quantifies the improvement. If your home tested at 10 ACH50 before and 5 ACH50 after, you have proof that the work was effective. If it barely changed, you know the contractor missed something.
Some rebate programs require this verification test. Even if yours doesn’t, it’s worth the $150 to $250 to know for certain that you got what you paid for. Using a smart power strip on your electronics after the audit helps you eliminate phantom loads that the audit may have identified.
Typical Cost Range and Factors
Here’s what energy audits and common improvements typically cost in 2026:
Energy audit costs:
- Basic walkthrough (no testing): Free to $100
- Standard audit with blower door test: $200 - $400
- Comprehensive audit (blower door, thermal imaging, duct testing): $350 - $600
- HERS rating: $400 - $800
Common improvement costs:
- Air sealing (attic, basement, penetrations): $800 - $3,000
- Attic insulation (blown-in): $1,500 - $4,000
- Duct sealing: $500 - $2,000
- Duct insulation: $800 - $2,500
- Weatherstripping and caulking: $100 - $500 (DIY) or $300 - $1,000 (professional)
- HVAC replacement: $5,000 - $15,000
Typical annual savings after improvements:
- Air sealing alone: $200 - $600/year
- Attic insulation: $300 - $800/year
- Duct sealing: $200 - $500/year
- Combined improvements: $600 - $1,800/year
What affects the cost:
- Home size. Bigger homes take longer to audit and require more materials for improvements.
- Home age. Older homes typically need more work and have more complex air leakage patterns.
- Climate zone. Cold climates benefit more from insulation, while hot climates benefit more from air sealing and radiant barriers.
- Current condition. A home with zero insulation improvements in 30 years will need more work than one that’s been maintained.
- Local labor rates. Vary by region, typically 20-40% higher in metro areas.
Red Flags vs. Green Flags
| Red Flag | Green Flag |
|---|---|
| ”Audit” is just a visual walkthrough with no testing equipment | Uses a blower door, infrared camera, and duct blaster as standard |
| No certification or refuses to share credentials | BPI certified or RESNET HERS Rater with verifiable credential number |
| Provides verbal recommendations with no written report | Delivers a detailed written report with test results, prioritized recommendations, and cost estimates |
| Recommends replacing everything without prioritizing by ROI | Ranks improvements by payback period and separates needs from nice-to-haves |
| Doesn’t test combustion safety on gas appliances | Performs combustion safety testing as standard procedure |
| Pressures you to sign a contract for improvements on the spot | Gives you time to review the report, get contractor bids, and make informed decisions |
| Claims your home “needs a full renovation” | Identifies specific problems with specific solutions and honest cost estimates |
Money-Saving Tips
- Start with air sealing. It’s almost always the cheapest fix with the fastest payback. A few hundred dollars in caulk, spray foam, and weatherstripping can eliminate the biggest energy drains.
- Check for utility rebates before you hire anyone. Many utilities rebate 50-100% of the audit cost and offer additional incentives for implementing recommendations. Don’t leave free money on the table.
- DIY the easy stuff. Weatherstripping doors, adding draft stoppers, caulking visible gaps, and insulating outlet covers on exterior walls are all weekend projects that cost under $100 and make a noticeable difference.
- Prioritize by payback period, not by comfort. The attic might be less exciting than new windows, but attic air sealing and insulation typically pay for themselves in 1-3 years while window replacement takes 15-30 years.
- Bundle improvements to save on labor. If a contractor is already in your attic to air seal, adding insulation at the same time is cheaper than scheduling a separate visit.
- Use the Inflation Reduction Act tax credits. You can claim up to $1,200 per year in credits for insulation, air sealing, and energy-efficient HVAC upgrades. That’s real money back on your tax bill.
- Get a post-improvement test. If the blower door number doesn’t improve significantly after the work, the contractor owes you a re-do. Without the test, you’ll never know.
Glossary
Blower Door Test: A diagnostic test that measures how much air leaks in and out of your home. A calibrated fan is mounted in an exterior door frame and depressurizes the house. The amount of air flowing through the fan at a standardized pressure tells you how “leaky” the home is, measured in ACH50 (air changes per hour at 50 Pascals of pressure).
ACH50: Air Changes per Hour at 50 Pascals. A standardized measurement of home air leakage. Lower numbers mean a tighter home. Most older homes test at 8-15 ACH50. A well-sealed home targets 3-5 ACH50.
R-Value: A measure of insulation’s resistance to heat flow. Higher R-values mean better insulation. Recommended R-values vary by climate zone and location in the home. Attic insulation in cold climates should be R-49 to R-60.
Thermal Bypass: A path where conditioned air escapes around or through insulation. Common examples include gaps around recessed lights, unsealed plumbing penetrations, and open wall cavities behind bathtubs. Insulation only works if air isn’t blowing through it.
HERS Rating: Home Energy Rating System score that rates your home’s energy efficiency on a scale where 100 represents a standard new home. Lower scores are better. A score of 70 means your home is 30% more efficient than the standard. Useful for comparison and required for some incentive programs.
Helpful Tools and Resources
Find cold spots, drafts, and insulation gaps around your home before and after the professional audit. A handheld thermal detector helps you verify that fixes actually worked.
Phantom loads from TVs, chargers, and gaming consoles waste $100-$200/year in most homes. A smart power strip cuts power to devices when they're off, eliminating the waste.
The gap under your exterior doors is one of the easiest air leaks to fix. A draft stopper takes two minutes to install and makes an immediate difference in comfort and energy use.
- BPI (Building Performance Institute): Find BPI-certified energy auditors in your area and learn about certification standards.
- ENERGY STAR Home Energy Assessment: Resources and tools for understanding home energy performance.
- DSIRE Efficiency Incentives: Search for state and utility rebates for energy efficiency improvements.
Quick Reference Checklist
Bring this to your energy audit appointment:
- What does the audit include, and what tests will you perform?
- Are you BPI or RESNET certified?
- What equipment do you bring?
- What is my home’s air leakage rate?
- Where are the biggest energy losses?
- What are the top three fixes with the best ROI?
- How much does the audit cost, and are there rebates?
- Will you provide a written report with costs?
- Can you estimate payback periods for each fix?
- Will you test for combustion safety?
- Are there moisture or air quality concerns?
- Do you also do the remediation work?
- Can you recommend qualified contractors?
- Are there financing programs or rebates for improvements?
- Should I get a follow-up audit after improvements?
Frequently Asked Questions
How often should I get a home energy audit?
Once every 5-10 years, or whenever you make significant changes to your home (adding rooms, replacing HVAC, major renovations). If your energy bills suddenly spike without an obvious explanation, that’s also a good reason to schedule one. The initial audit is the most valuable because it identifies the baseline issues. Follow-up audits verify that improvements are working and catch new problems.
Can I do my own energy audit?
You can do a basic walkthrough: check for drafts around windows and doors, look at attic insulation levels, and inspect visible ductwork for gaps. A handheld thermal leak detector helps identify cold spots. But you can’t replicate a professional blower door test, infrared thermal scan, or duct leakage test with consumer tools. Think of the DIY version as a screening, not a diagnosis.
How long does a professional energy audit take?
A comprehensive audit typically takes 2-4 hours for an average-sized home (1,500-2,500 square feet). Larger homes or those with complex systems may take longer. The blower door test alone runs about 30-45 minutes. You should be home during the audit so you can ask questions and see the results in real time.
Will my utility company do a free energy audit?
Many utilities offer free or heavily subsidized energy audits. Some send an auditor to your home; others provide an online tool based on your billing data. The free versions are usually less comprehensive than a paid professional audit, but they’re a good starting point. Call your utility’s customer service line or check their website for available programs.
What is the difference between an energy audit and a HERS rating?
An energy audit identifies problems and recommends fixes. A HERS rating produces a standardized score (similar to a miles-per-gallon rating for your home) that can be used for comparison, real estate listings, and some incentive programs. Some auditors provide both. If you’re selling your home or applying for energy-efficient mortgage programs, a HERS rating adds value. For most homeowners focused on reducing bills, a standard audit with a blower door test is sufficient.