The contractor as well as the work. Keller’s fee schedule lists a $100 mechanical permit when no building permit covers the job, and the city only issues permits to registered contractors holding a state air conditioning license and $300,000 in insurance or a bond.
Federal ones. New home systems may not use a refrigerant with a global warming potential of 700 or more unless all specified components predate 2025, and the EPA ended production and import of R-22 in 2020.
No. Square footage is one input, with insulation, windows, ductwork and sun exposure. Four or more bedrooms is the norm here, 59 percent of Keller homes, and two houses with the same footage can need different systems.
At least 14.3 SEER2 below 45,000 Btu per hour and 13.8 SEER2 above that, under the federal standard for Texas split-system air conditioners installed since January 1, 2023.
Plan for it. The Census puts 29 percent of Keller homes in the 2000s, so a system original to one is 17 to 26 years old, past the 10 to 15 years where replacement usually makes sense.