1. Sizing from a chart instead of a load calculation
Square footage alone does not tell you what a house needs. Window area, orientation, insulation, ceiling height, and how tight the envelope is all change the answer. Oversized equipment short-cycles, never dehumidifies properly, and wears out early. We run a Manual J calculation on every plan.
2. Ducts designed after the framing
When ductwork is an afterthought, it gets crushed through tight chases, run too long, and starved of return air. The result is the back bedroom that is always five degrees off. Bring the HVAC contractor in at the plan stage and duct routing becomes part of the design.
3. Not enough return air
Big supply, tiny return is the most common defect we find in new homes. It makes the system loud, cuts airflow, and pulls attic air through every gap in the house. Every bedroom with a closing door needs a return path.
4. One zone for a two-story or long ranch house
Heat rises and the sun moves. A single thermostat cannot make an upstairs and a downstairs, or an east wing and a west wing, comfortable at the same time. Zoning or a second system costs less during construction than it ever will after.
5. Ruling out geothermal too early
On an acreage build, the ground loop can go in while the excavator is already on site, which removes most of the extra cost that makes geothermal expensive as a retrofit. It is the quietest, lowest-operating-cost system you can put in a custom home, and we install ClimateMaster units built in Oklahoma City. At least get the number before you decide.
Need a hand with this?
Call or text (405) 615-2707. Same day on most calls around Washington, Purcell, and Norman.