After doing your air sealing, insulation, and equipment swaps, a professional energy audit tells you how much you’ve improved — and what you missed. It’s also a good starting point if you haven’t made any changes yet and want a roadmap.
Your utility sends a trained auditor to your home with two key tools: a blower door (which pressurizes your house to measure air leakage precisely) and an infrared camera (which reveals exactly where insulation is thin or missing, and where air is moving). This is $0 to you. Your utility pays for it.
Infrared cameras work best when there’s at least a 15°F difference between inside and outside temperatures. In California, schedule for early morning in winter (December–February) for the clearest thermal images.
They’ll ask about your comfort complaints (rooms that are too hot, too cold, drafty), your utility bills, your HVAC system age, and any recent improvements. Have your last 12 months of utility bills available if you can — they may ask for them. Your utility’s online portal usually has these.
The auditor installs a calibrated fan in your front door and seals around it. They depressurize the house and measure how much air flows in through leaks. The result is your home’s ACH50 (air changes per hour at 50 Pascals pressure). California Energy Code target for new homes is about 5.0 ACH50. Many older homes are 10–20+. The test takes about 20 minutes.
While the blower door runs, the auditor walks through with the infrared camera. Cold spots appear blue (air infiltration), hot spots appear orange (thermal bridging or heat loss). You can literally see your insulation gaps on a screen in real time. The auditor photographs every issue for the report.
The auditor checks your ducts for leakage (a major hidden loss in many CA homes — ducts in unconditioned attics can lose 20–30% of airflow), inspects your furnace or AC unit, and notes the age and efficiency rating. Leaky ducts are often a bigger problem than the equipment itself.
Within a week, you receive a written report listing issues found, their estimated energy impact, recommended fixes, and available rebates for each. This becomes your upgrade roadmap — prioritized by actual data from your specific house, not generic advice.
Utility audits are excellent but sometimes brief. For a deeper dive — especially if you’re planning significant renovations — hire a BPI (Building Performance Institute) certified auditor independently. They run more detailed diagnostics and provide more comprehensive reports. Cost: $200–$500.
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