QUICK ANSWER
Castle Air Conditioning & Heating repairs air conditioners across Katy, TX, from Cinco Ranch and Seven Meadows through Firethorne, Grand Lakes, Nottingham Country and Cane Island. We are based in Fulshear, so Katy is a short drive rather than a cross-city trek. Call in the morning and we will usually reach you the same day. All makes and models, NATE-certified technicians, and a written quote before any work starts. Call or text (713) 667-7606.
Air conditioner down right now?
Call or text (713) 667-7606. We answer 24 hours a day. If water is coming through a ceiling, you can smell burning, or the breaker keeps tripping, treat it as urgent and call rather than waiting for a form reply.
Why Katy gets us out more than most of our service area
Katy is the largest single area we cover, and it is unusual in a way that matters for air conditioning. The city spans three counties, Harris, Fort Bend and Waller, and the housing stock spans about thirty years with it.
In the newer master-planned communities the equipment is young and the faults are installation-related or drainage-related. In Nottingham Country, Kelliwood, Green Trails and the older parts of Cinco Ranch, a lot of systems are now fifteen to twenty-five years old, which is precisely the window where compressors, coils and capacitors start to go. Those are two different service calls, and it is useful to know which one you are likely having before anyone arrives.
The repairs we are called out for most in Katy
Poor airflow
The most common call, and often the cheapest fix. A clogged filter, a closed or blocked return, or a duct problem starves the system of air. That makes the coil colder than it should be, which is how a system ends up frozen solid in July. If one room never cools while the rest of the house is fine, airflow is usually where we start rather than the equipment.
Refrigerant that is too low, or occasionally too high
An air conditioner does not consume refrigerant. If the charge is low there is a leak, and topping it up without finding the leak is money poured into the attic. Low charge shows up as air that is cool but never quite cold, a system that runs constantly, or ice on the refrigerant line. Overcharging causes its own problems and is usually the legacy of someone guessing rather than measuring.
Electrical components
Capacitors, contactors and fan motors. Small parts, and the difference between a system that starts and one that hums and does nothing. A weak capacitor found during a spring service is a minor part fitted at your convenience. The same capacitor found on the first 98-degree Saturday is a hot house and a wait. This is the single best argument for having the system looked at before the season.
Blocked condensate drains
The one that does the most damage. Most Katy homes have the air handler in the attic, directly above a ceiling, and a blocked drain line means the pan fills and the water has somewhere unfortunate to go. A float switch should shut the system down before that happens, which is why a Katy air conditioner that has stopped for no obvious reason is very often a drainage problem rather than an equipment failure.
It is also largely preventable. See how to clear a clogged AC drain line for the signs and the fix.
Systems reaching the end of their life
In the older Katy neighbourhoods we are increasingly asked whether a repair is worth doing at all. That depends on the age of the equipment, what has failed and how long you plan to stay in the house. We will tell you honestly when a repair is the better spend, and when it is not. Our guide to choosing between repair and replacement sets out how we think about it.
How quickly we can get to Katy
We are based in Fulshear, which puts Katy closer to us than it is to most of the companies advertising in it. If you call in the morning we will usually reach you the same day. The honest exception is a day that is already fully booked, in which case we will tell you on the phone rather than leave you waiting on a technician who is not coming.
Outside normal hours we still answer, and we will come out for a genuine emergency. Out-of-hours work carries a premium and we tell you what it is before anyone is dispatched, never afterwards.
What a repair visit involves
| Step | What happens |
|---|---|
| 1. You call or text | A person answers, day or night. Describe what the system is doing. |
| 2. We triage | We tell you plainly whether this needs attention today or can safely wait until morning. |
| 3. We diagnose | A NATE-certified technician measures temperatures, pressures, airflow and charge rather than swapping parts until the symptom goes away. There is a diagnostic fee, billed separately from the repair. |
| 4. You get a price | A written quote before any work starts. You decide. Nothing happens without your say-so. |
If you are on our Set It and Forget It maintenance plan, 10% comes off the work.
Where in Katy we work
Across the whole of Katy and the surrounding communities, including Cinco Ranch, Seven Meadows, Grand Lakes, Firethorne, Nottingham Country, Kelliwood, Green Trails, Cane Island, Elyson, Jordan Ranch and the neighbourhoods around Katy Mills. If you are not sure whether you are inside our area, call and tell us the cross streets.
We also cover neighbouring Fulshear and Cross Creek Ranch, along with Sugar Land, Richmond and the wider southwest Houston area.
How to avoid most of this
Most of what we are called out for in July was visible in March. A weak capacitor, a fouled coil, a low charge or a drain line starting to close up are all things a spring service catches while they are still cheap. Our Houston maintenance schedule sets out what to check and when, including the jobs worth doing yourself between visits.
Why Katy homeowners call us
- Based in Fulshear, so Katy is local rather than a long drive
- Family owned, licensed under TACLA #00051749C, and insured
- NATE-certified technicians
- All makes and models, including equipment we did not install and warranty work
- A written quote before any work begins
- 4.9 stars from 200 Google reviews
- We do not buy radio or television advertising, so that cost is not built into your bill
Frequently asked questions
Do you offer same-day AC repair in Katy?
Usually, yes. If you call in the morning we will normally reach you the same day. If the schedule is already full we will say so on the phone rather than leave you waiting. Katy is one of our closest service areas, so we are rarely far away.
How much does AC repair cost in Katy?
It depends entirely on what has failed. A capacitor and a compressor are not the same conversation. We charge a diagnostic fee to find out properly, then give you the repair price in writing before any work starts. We have written up what AC repair actually costs in the Houston area.
My AC in Katy stopped working for no obvious reason. What is it?
Very often the condensate drain. When the drain line blocks, the pan fills and a float switch cuts the power so water cannot reach your ceiling. Check the breaker and the thermostat batteries too, but if the pan is full, the drain is the thing to deal with.
Do you cover Cinco Ranch and the newer Katy communities?
Yes. Cinco Ranch, Seven Meadows, Grand Lakes, Firethorne, Cane Island, Elyson and the rest. We are based in Fulshear, so most of Katy is a short drive for us.
Will you work on a system you did not install?
Yes. All makes and models, including warranty work, whoever originally fitted it.
My house is older. Is it worth repairing or should I replace?
It depends on the age, what has failed and how long you plan to stay. Plenty of the older Katy systems we see have years left in them. We will tell you honestly when a repair is the better spend and when it is not.
Do you handle commercial AC repair in Katy?
Yes. Rooftop units, packaged systems, commercial splits and server-room cooling. See our commercial HVAC services.
Your Houston HVAC Maintenance Schedule
What to check and when, and why humidity makes systems here behave differently from the same equipment further north.
Published by Castle Air Conditioning & Heating. Licensed TACLA #00051749C. NATE-certified technicians serving Katy, Fulshear, Fort Bend County and southwest Houston. Quotes in writing before work begins. Last reviewed September 2026.
AC repair in Katy? Call or text (713) 667-7606.
