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Blower door tests are measured in a few different ways, but the most popular are air changes per hour (ACH) and cubic feet of air (CFM) moving through the house per hour. A good ACH score is less than 2ACH, but 1ACH is better. This means the house experiences a total air change within 60 minutes (for 1ACH). For 2ACH, there’s a complete change every 30 minutes, and so on. CFM scores are similar in that a lower score means less air change, and therefore less leakage.

A home energy audit costs about $420 on average, with prices ranging from $100 to $2,250 or more. The final cost depends on factors like your home's size, location, the thoroughness of the audit, and the specific tests performed. A basic Level 1 walk-through inspection typically costs between $150 and $200, while a comprehensive Level 3 audit with detailed testing and a report costs around $900. Homeowners may be able to use the 2022 Inflation Reduction Act’s Energy Efficient Home Improvement credit to cover up to $150 of the audit cost.

Costs for common individual tests include:

• Blower door test: $350

• Duct testing: $100

• HERS test: $375

• HERS certification: $200

• Infrared imaging: $200

A blower door test shouldn’t take more than an hour, and most can be completed in less than 30 minutes. Expect the test to take longer once you start searching for leaks with thermal imaging or want to include sealing such leaks in the time estimate. The test doesn’t take much time and can’t be rushed, but it will take longer in large homes or those with many air leaks.

Window AC units use a fair amount of electricity, but significantly less than central AC systems. Because they are more energy-efficient for cooling individual rooms or small spaces, their usage is comparatively low. On average, a window AC unit consumes between 500 and 1,400 watts, while a central AC system uses over 3,500 watts—meaning a window unit uses about one-third of the energy. This typically translates to a monthly running cost of $15 to $40, although this can vary depending on external factors.