Why the number is so large
If you are on an annual billing arrangement, your true-up is the reconciliation of twelve months of usage against twelve months of generation and credits. The summer months in Fresno do most of the work in that calculation, because that is when a 3–5 kW compressor is running for hours a day, and often running during the exact hours when energy is priced highest.
What makes a true-up painful is not usually a single bad month. It is a pattern: five or six months where evening AC use quietly accumulated.
Read the statement before you change anything
- Find the monthly usage breakdown. Compare June through September against February. The difference is your cooling load, near enough.
- Look at the peak-hour split. Most time-of-use plans separate peak from off-peak usage. If a large share of your summer kilowatt-hours landed in the peak window, that is the expensive finding.
- Check the plan itself. Rate plans change. The plan that suited your household three years ago may not suit the way you actually use energy now.
To fill in: the rate and bill figures in this article are illustrative arithmetic with the assumptions stated inline. Check them against current PG&E / SCE residential rates before publishing, and update the date on the article when you do.
What a whole house fan changes
Peak pricing windows and the hours a whole house fan is most useful overlap almost perfectly. The fan does its best work from late afternoon onward, which is precisely the block of hours you are being charged most for. Shifting evening cooling from a compressor to a few hundred watts of fan does two things at once: it cuts the kilowatt-hours, and it cuts them out of the most expensive tier.
Then the overnight run compounds it. A house cooled to outside temperature overnight does not call for cooling at 2 pm the next day — it calls for cooling at 5 pm, and for less of it.
Things worth doing in the same season
- Attic venting. An under-vented attic at 150°F radiates into your ceilings all evening. Fixing venting improves both the fan and the AC.
- Damper sealing. If you already have a whole house fan with a leaking damper, you are losing heated air every winter and never seeing it on a line item.
- Duct leakage. Attic ductwork losing conditioned air into a superheated attic is one of the most expensive faults in Valley homes.
- Thermostat schedule. Pre-cooling before the peak window starts costs less than cooling during it.
Setting expectations honestly
A whole house fan will not zero out a true-up. What it does is remove a large, predictable block of evening and overnight compressor hours from next summer’s total, and move the rest to a cheaper part of the day. For most Central Valley households that is the single largest cooling change available short of replacing the HVAC system.
If you want a specific number for your house, we can walk your attic and give you a realistic estimate based on your floor plan, your existing venting and how you actually use your AC.