AC Repair & HVAC Contractors in Castle Hills

Heating and Cooling in Castle Hills, TX

Castle Hills is a city of about 3,978 people (2020 Census). It covers about 2.5 square miles, is surrounded by San Antonio and is split by Loop 410. It is a mix of neighborhoods and businesses. Older homes often have long duct runs through the attic. A system that worked when the house was built may now struggle after additions, enclosed patios or a changed floor plan.

Castle Hills has its own permit office, so the rules below apply instead of San Antonio’s. The contractor list above is a directory, not an endorsement.

Heat, Attics and Sizing in Castle Hills

Cooling is the main job for any system here. At the San Antonio airport weather station, the 1991–2020 normals average about 122 days a year at 90°F or hotter, with a normal August high of 96°F. The same record shows roughly 3,148 cooling degree days against 1,438 heating degree days, so an air conditioner works more than twice as hard over a year as a furnace or heat pump does in heating mode. Winter still matters: the normals also average about 14 nights a year at or below freezing.

The DOE places Bexar and Guadalupe counties in climate zone 2A (hot-humid). For an attic in zone 2, ENERGY STAR recommends insulating to R49 when there is none, or adding R38 on top of 3–4 inches of existing insulation. That matters because many homes in this area run their ductwork and air handler in the attic, which can get far hotter than the outdoor air on a summer afternoon. Leaky or poorly insulated ducts there pull hot attic air into the system, so before you buy a larger unit, ask the contractor to check the duct connections, the insulation depth and the return air path.

System Types You Will See in Castle Hills

• Split AC with a gas furnace. An outdoor condenser plus an indoor coil on top of a gas furnace. This is common in Castle Hills homes that have gas service. When a furnace is replaced, ask the contractor to check the flue and the gas connection as part of the job.
• Heat pump. One outdoor unit that cools in summer and reverses to heat in winter, usually with electric backup heat strips for freezing nights. It suits all-electric homes, and it is the type that both CPS Energy and GVEC rebate programs cover.
• Ductless mini-split. Wall or ceiling heads fed by an outdoor unit, often used for garage conversions, additions and rooms the main ducts never reached. CPS Energy rebates cover mini-splits; GVEC’s rebate does not.

Efficiency floor. CPS Energy’s rebate minimum for a central or mini-split AC under 45,000 BTUh (under about 3.75 tons) is 14.3 SEER2, or 13.8 SEER2 at 45,000 BTUh and above. Ask for the AHRI certificate number for the exact outdoor unit, coil and furnace or air handler combination on your quote, because that certificate is what the utilities use to check the rating.

Refrigerant. New systems now commonly use lower-GWP refrigerants such as R-454B or R-32 in place of R-410A. In a May 26, 2026 rule, EPA removed the federal installation deadline for R-410A split systems as long as every component was made or imported before January 1, 2025. If a quote lists an R-410A system, ask for the manufacture dates, and see our refrigerant guide for what each type means for future repairs.

Castle Hills Permits and Inspections

• Who applies. The city says permits are obtained by the contractor or licensed trade doing the work. A homeowner may do their own work where state law allows.
• Codes. Castle Hills has adopted the 2021 ICC codes and the 2020 Energy Conservation Code.
• Do not start early. Work started without a permit pays a double permit fee.
• Inspections. The city says many repair and replacement permits need only a final inspection. Requests made by 2 p.m. are scheduled for the next business day.
• Contact. The permit office is open Monday–Thursday 8–4 and Friday 8–3. Reach the Permits Clerk at 210-293-9675 or permits@castlehills-tx.gov.

Utility Rebates for Castle Hills Homes

CPS Energy. If your electric bill comes from CPS Energy, its 2026 residential HVAC rebate covers central AC, central heat pumps and ductless mini-splits installed from February 1, 2026 through January 31, 2027. According to CPS Energy’s published table, the rebate pays $90 to $275 per cooling ton for replace-on-burnout jobs and $115 to $310 per cooling ton for early replacement of a working system, rising with the SEER2 tier. The main conditions are:

• It must be a one-for-one replacement in an existing home, installed by an HVAC contractor licensed in Texas.
• Your contractor’s invoice must list the model and serial number of each new indoor and outdoor unit, and it must match an AHRI certificate.
• To claim the early-replacement rate, the old central system must still work and be under 25 years old (under 20 for heat pumps), and you need photos plus its model and serial numbers.
• Apply within 30 days of completion. CPS Energy asks for a permit number on jobs inside San Antonio city limits.

Check the License Before Anyone Opens the Unit

Under Texas law, anyone who installs, repairs or maintains air conditioning, refrigeration or heating systems must hold a TDLR license, and every ACR company must employ a licensed ACR contractor at each permanent location. Search the company or contractor name in the TDLR license search and compare the number with the one printed on the quote and the truck. The listings above show the TDLR number where one has been provided. Also ask for a certificate of insurance and a written warranty that covers both parts and labor.

Nearby Areas and Guides

This page is part of our Central San Antonio AC repair contractor guide. You can also compare contractors in neighboring areas:

Planning guides for homeowners: