If you're trying to maximize total savings, the priority order for most Oklahoma homes looks like this:
- Attic insulation & air sealing first. Oklahoma homes lose conditioned air to attics that hit 140°F+ in summer. Sealing and insulating before replacing HVAC means you can size the new system smaller — and the rebate plus the avoided oversize is substantial.
- HVAC or heat pump replacement. Cooling is half your bill. A high-SEER2 replacement is the biggest single rebate most Oklahomans claim.
- Water heating. Heat pump water heaters carry meaningful federal credits and growing utility rebates, with payback periods that have shortened dramatically.
- Cool roofing. Best timed when you're already replacing your roof — the incremental cost is small and the cooling reduction is real.
- Windows & doors. Long payback periods mean these are usually best done as part of a remodel or to address a specific comfort issue, not as a pure efficiency play.