HVAC Energy Audit Checklist — Find Where You're Losing Money (2026)

Find the nameplate on each unit and record: manufacturer, model number, serial number (which encodes the manufacturing date), and efficiency rating (SEER/SEER2 for AC, AFUE for furnace, HSPF/HSPF2 for heat pump). A 15-year-old AC at SEER 10 uses roughly 40% more electricity than a new SEER 16 unit for the same cooling output. Knowing your baseline efficiency tells you whether equipment replacement should be the top priority.

Current federal minimums are SEER2 13.4–14.3 for ACs (region-dependent), 80–90% AFUE for furnaces (region-dependent), and HSPF2 7.5 for heat pumps. If your equipment falls below current minimums, replacement delivers guaranteed efficiency gains. Equipment at or above current minimums may still benefit from newer technology, but the payback period is longer.

Oversized HVAC equipment is one of the most common energy waste problems in residential systems. An oversized AC cools the house quickly but shuts off before adequately dehumidifying — resulting in a cold, clammy house and short-cycling that wastes energy. Compare the equipment tonnage to a Manual J load calculation for your home. Many older installations are oversized by 0.5–1.5 tons because contractors used outdated rules of thumb.

A duct blaster test pressurizes the duct system and measures how much air leaks out. The result is expressed in CFM25 (cubic feet per minute at 25 pascals of pressure). A tight duct system leaks less than 4% of total system airflow; a typical older home leaks 20–30%. This single test tells you more about HVAC energy waste than any other measurement. Cost: $150–$300 as part of an energy audit.

Walk your attic, basement, and crawl space and visually inspect all accessible ductwork. Look for: disconnected joints (common with flex duct), gaps at boots and registers, deteriorated cloth duct tape (loses adhesion within 1–5 years), and crushed or kinked flex duct. A single disconnected duct joint in an attic can waste $200+ per year in heating and cooling costs.

Ducts running through attics, crawl spaces, and garages lose heat (or gain heat in summer) through the duct walls. Current code requires R-8 insulation on ducts in unconditioned spaces. Many older homes have R-4 or even uninsulated ductwork. In a 130°F attic, uninsulated ducts delivering 55°F air lose 15–20% of their cooling capacity before reaching the register.

Using a flow hood or anemometer, measure the actual CFM delivered to each room and compare to the design requirement. Rooms receiving less than 80% of design airflow have duct restrictions, leaks, or balancing issues. Rooms with excessive airflow may be compensating for undersized ducts elsewhere. This room-by-room measurement reveals distribution problems that total system airflow doesn't show.

A blower door test depressurizes the house and measures total air leakage in ACH50 (air changes per hour at 50 pascals). A tight house is under 3 ACH50; the average existing home is 7–10 ACH50. Every reduction of 1 ACH50 saves roughly 3–5% on heating and cooling costs. This test identifies whether air sealing should be a priority before considering equipment upgrades.

Measure the depth of attic insulation in several locations. Current code for most climate zones requires R-38 to R-60 in the attic (roughly 10–17 inches of fiberglass batts or 10–15 inches of blown cellulose). Insulation that has settled, been compressed by stored items, or has gaps around penetrations performs well below its rated value. Adding attic insulation from R-19 to R-49 can save 10–20% on heating costs in cold climates.

Check weather stripping on all exterior doors for compression, cracking, and gaps. Check caulking around window frames for cracks and separation. A 1/8-inch gap around an exterior door leaks as much air as a 3-inch-diameter hole in the wall. Replacing weather stripping costs $5–$15 per door and caulking costs $5–$10 per window — among the cheapest energy improvements available.

Identify what you have: manual (no programming), programmable (set schedules), or smart (learning algorithms plus remote access). A non-programmable thermostat left at a constant temperature wastes energy during unoccupied hours. If you have a programmable thermostat that's never been programmed — which describes roughly 40% of homes with programmable thermostats — that's an immediate zero-cost savings opportunity.

The Department of Energy recommends: 68°F when occupied in winter, 60–62°F when sleeping or away; 78°F when occupied in summer, 85°F when away. Each degree of setback saves approximately 1–3% on heating or cooling costs. Verify the programmed schedule matches your actual occupancy pattern — many households have outdated schedules from when work patterns were different.

Place a calibrated thermometer next to the thermostat and compare readings after 15 minutes. A thermostat that reads 3°F high means the system runs longer than necessary. Also verify placement: the thermostat should be on an interior wall, 52–60 inches above the floor, away from direct sunlight, supply registers, exterior doors, and heat-generating appliances. Poor placement causes the thermostat to misread the house temperature.

Request 12 months of electric and gas usage data from your utility company (most provide this online). Plot monthly usage to identify the heating and cooling baseload. The difference between your lowest-usage month (spring/fall) and peak months (January/July) represents your HVAC energy consumption. If peak months are 3–4x the baseload, the HVAC system and/or building envelope need attention.

Divide your annual HVAC energy cost by your home's square footage. Efficient homes in moderate climates spend $0.50–$1.00 per square foot per year on heating and cooling. Homes spending $1.50+ per square foot have significant efficiency opportunities. This metric makes it easy to compare against benchmarks and track improvement over time.

Many utility companies offer free or reduced-cost energy audits as part of demand-side management programs. These audits often include blower door testing, duct leakage testing, and infrared imaging — services that would cost $400–$600 privately. Check your utility's website or call their energy efficiency department. Some programs also offer rebates for recommended improvements.