The pieces of a replacement
A full replacement usually includes the outdoor condensing unit, the indoor coil or air handler, the refrigerant lines, the pad or stand, the condensate drain, the thermostat, the permit, and the labor to install and start it up. A quote that leaves some of these out is not a cheaper version of the same job. It is a different job, so ask for the list.
System size comes from a calculation, not a rule of thumb
Square footage alone does not size an AC. Insulation, windows, sun exposure and duct layout all matter. A unit that is too big cools fast, shuts off early and leaves the air damp. One that is too small runs all afternoon. Sizing also affects price, because bigger equipment costs more.
Efficiency rating (SEER2)
The federal minimum for a split-system AC under 45,000 Btu/h in Texas is 14.3 SEER2. Higher ratings cost more up front and can lower the electric bill. Ask how much each step up changes your bill, and whether the rating is for the full matched system or only the outdoor unit.
Single-stage, two-stage or variable speed
More capable equipment holds a steadier temperature and removes more moisture, which Houston’s humidity makes worth asking about. It also costs more, and it needs a properly installed system to deliver on that.
Whether the indoor side changes too
Replacing only the outdoor unit costs less than a full system, but a mismatched coil can hurt performance and may affect the warranty. Your technician looks at the indoor coil, the air handler or furnace and the age of each.
Ductwork
New equipment on leaky, undersized or crushed ducts will not perform like new equipment. Duct repair or replacement adds to a quote, and skipping it can cost more in comfort and electricity. Ask what the technician found.
Refrigerant and the 2026 rules
New equipment uses R-454B or R-32 rather than R-410A. The federal 25C tax credit for AC replacements ended after December 31, 2025, so there is no federal credit to subtract in 2026.
Access and the permit
An attic air handler takes more labor than a unit in a closet. The City of Houston requires a mechanical permit for an AC replacement, pulled by a City-registered contractor, plus an inspection. Ask who pulls it and whether it is in the price.
Sources: U.S. Department of Energy minimum efficiency standards; EPA refrigerant transition rules; IRS Section 25C; City of Houston Permitting Center. Updated November 2026.
