A home energy audit in Menlo Park, Atherton or Portola Valley should answer two questions: where does your house lose the air you paid to heat or cool, and how much of what the system produces actually reaches the rooms? Ours is an HVAC-focused check. It uses a blower door, duct leakage testing and thermal imaging, and puts extra weight on the heating and cooling equipment and the ducts. It is not a certified audit program and does not produce an official rating. What it gives you is measurements and a ranked list of fixes.
What gets measured
| Test | What it measures | What it often turns up |
|---|---|---|
| Blower door | Whole-house air leakage, with a calibrated fan holding the house at a set pressure | Gaps at the attic hatch, recessed lights, pipe and wire holes, fireplace dampers |
| Thermal imaging | Surface temperatures across ceilings, walls and floors | Missing or settled insulation, leaks around windows and wall tops |
| Duct leakage test | Air lost from the duct system itself | Disconnected runs, leaky joints, open returns in the attic or crawlspace |
| Equipment and airflow | Temperature change across the coil, static pressure, airflow, filter condition, age and rated efficiency | Restricted airflow, oversized or tired equipment |
| Thermostat and controls | Settings, schedules, heat pump backup-heat use | Electric backup heat running when the heat pump alone would do |
How the visit runs
- Walk-through with you. Which rooms are uncomfortable, when the bills spike, and any plans for the house.
- Outside, attic and crawlspace. Insulation depth and coverage, duct condition, where the equipment sits.
- Blower door. The fan is set in an exterior doorway and the house is depressurized. With outside air pulling in through every gap, the thermal camera shows where it enters.
- Duct test. Registers are covered and the duct system is pressurized on its own.
- Equipment check with the system running in heating or cooling.
- Report with the results and the ranked list.
Thermal imaging needs a real temperature difference between inside and out. In a mild climate the blower door supplies much of the contrast, and cool mornings give the camera the most to work with.
Reading the report: what usually comes first
Fixes are ranked by what they change for the money, not by how large they are. In most homes the order looks like this:
- Air sealing at the attic floor and other large openings.
- Duct sealing and reconnection, handled as duct repair.
- Attic insulation where it is thin, settled or disturbed. Sealing comes before insulating, because insulation laid over open gaps does not stop the air.
- Controls: thermostat setup, schedules and heat pump settings, sometimes a new thermostat.
- Equipment replacement, last, because the first four change how big the new system needs to be.
What older, larger and foothill homes tend to show
Older homes. Many Menlo Park houses are more than 50 years old, with ducts in the attic or crawlspace and insulation that is patchy or has been pushed aside by decades of wiring and repairs. In these houses the duct test and the attic inspection usually account for most of the findings.
Large homes with zones. In Atherton, a house with two or three systems or a zoned system gets each one tested on its own. Long runs to far wings and lower levels are where duct losses add up, and one zone can be the outlier in an otherwise tight house.
Foothill homes. In Portola Valley, spread-out homes on hillside lots see hot summer afternoons and cooler nights, so heat coming in through ceilings and sun-facing glass matters as much as winter loss. The same leaks that let conditioned air out let dust and pollen in, and on wildfire-smoke days a leaky house lets more smoke in with the windows closed. Sealing helps with all three.
Cost and timing
An energy audit runs $200 to $500 and takes 2 to 4 hours on site. House size, attic and crawlspace access, and the number of systems to test move the price, which is confirmed in writing before the visit. If the report points toward new equipment, estimates for new and replacement systems are free.
Rebates and what this check is not
Air sealing, insulation, duct sealing and heat pumps are the kinds of upgrades that utility, regional and state programs often support, and a report with measurements helps you plan around them. Programs set their own rules; some require testing by their own rater before and after the work, and this check does not replace that. See rebates for what to look at before counting on one. If you are planning a heat pump installation, the audit’s findings feed straight into sizing it.
To get the most from the visit
Have a year of utility bills handy if you can, clear a path to the attic hatch and crawlspace entry, and list the rooms that feel wrong and when. If your concern is dust, smoke or humidity rather than bills, an indoor air quality check measures those directly.