How-to

How to Do a Home Energy Audit (DIY and Professional)

Updated Oct 28, 2026 2 min read By the WieHow – Home, Energy & Money Guides editorial team
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Quick answer

A DIY audit means checking for air leaks, insulation levels, heating and cooling equipment, water heating and lighting. A professional audit adds a blower door test and an infrared camera, typically costs a few hundred dollars and is often subsidized by utilities. Fix the cheapest, biggest problems first: air sealing, insulation and thermostat settings.

On this page
  1. Step by step
  2. Professional energy audits
  3. Typical findings and priorities

Most homes waste energy in a handful of predictable places. An energy audit finds them so you spend money where it matters most.

Step by step

  1. Collect a year of energy bills

    Note monthly electricity and gas usage. Big seasonal swings point to heating and cooling as the main costs.

  2. Look for air leaks

    Check around windows, doors, outlets on exterior walls, attic hatches, plumbing penetrations and recessed lights.

  3. Check insulation

    In the attic, measure insulation depth. In walls, remove an outlet cover (power off) and look for insulation behind the box.

  4. Inspect heating and cooling

    Note the age of your furnace, AC or heat pump, check the filter and look for disconnected or leaky ducts.

  5. Check the water heater

    Note its age and temperature setting (120 °F is recommended) and insulate accessible hot water pipes.

  6. Review lighting and appliances

    Replace remaining incandescent bulbs and measure old refrigerators and freezers with a plug-in meter.

  7. Make a priority list

    Rank fixes by cost and impact. Air sealing and insulation usually come first.

Professional energy audits

A certified auditor uses a blower door to depressurize the house and measure how leaky it is, and an infrared camera to see missing insulation and air leaks. Many utilities offer free or discounted audits; independent audits typically cost a few hundred dollars. The report ranks improvements by cost and expected savings.

Typical findings and priorities

FindingTypical fixCost
Attic air leaksSeal with caulk and foamLow
Thin attic insulationAdd insulation to R-38–R-60Medium
Leaky ducts in attic or crawl spaceSeal with masticLow–medium
Old furnace or ACReplace with high-efficiency systemHigh

Start by estimating your current heating cost:

Home Heating Cost CalculatorEstimate your yearly and monthly heating billTry the calculator →

Frequently asked questions

How do I find a qualified energy auditor?

Ask your utility first. Look for auditors certified by recognized building-performance organizations, and check reviews.

How much can an audit save?

It depends on what is found. Homes with poor insulation and many air leaks can often cut heating and cooling costs significantly after the recommended fixes.

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