Size the house at the real outdoor temperature
Four answers. A heating and cooling load using the ASHRAE outdoor temperature for that state. Show the math when they ask how you got it.
New/ducted home: a central air handler reuses the duct distribution.
Coverage band: undersized. Deal basis: estimated.
2 x 20x25 filter-back return (or 400-800 sq in net free area equivalent)
Airflow rules of thumb (400 CFM per ton nominal, 350 humid / 450 dry; return free-area sizing). Confirm with a static-pressure test and Manual-D before install.
Plan for this house
New/ducted home: a central air handler reuses the duct distribution.
Lead with New ducted heat pump: One central heat pump that reuses the duct distribution for whole-home heating and cooling. Present the 1 brand-neutral fallback option(s) only if the homeowner declines the heat pump, and always price the lit option beside any fallback.
- No fossil furnace on file. Confirm the existing heat source before setting a dual-fuel switchover; otherwise size electric backup or run heat-pump-only.
- Run is 0.4 ft past the 24.6 ft factory pre-charge: add refrigerant per the model charge rate (see refrigerantChargeEstimate) and weigh it in.
- Confirm the O/B reversing-valve orientation against the equipment (most energize O on cool).
- A C (common) wire is required for modern wifi / smart controls. Verify a true common is landed, not a jumper.
- Maintain condenser clearances: ~12 in sides, 24 in service side, 60 in overhead, 6 in back. Confirm exact values against the model install manual.
- Confirm the condensate path: gravity drain if a downhill route exists, otherwise a condensate pump with a float safety switch.
- Snow region: mount the condenser on a stand/riser above the expected snow line, keep the base-pan drain clear, and protect from roof-shed ice. Wall brackets help in heavy drift.
- Coastal / salt air: specify a corrosion-protected coil and schedule periodic fresh-water coil rinses to fight salt corrosion.