What it is
Your AC pulls humidity out of the air and drains it away. When algae blocks that drain, water backs up, a float switch trips, and the system shuts off to avoid flooding your house.
What you would notice
- The system shut off by itself and will not restart
- Water pooling around the indoor unit or a stain on the ceiling below it
- A full drain pan
- It happens on the most humid days
Can you do this yourself?
You can do this
This is the friendliest repair on the list. There is no electricity involved and no refrigerant. The float switch that shut your system down is doing its job — it stopped the unit before water damaged your ceiling.
What to say when you call
Red flags
- A quote in the four figures for a drain clog
- Being sold a whole new air handler over standing water
The call-out alone runs $100–$250 before any work, plus $40–80/hr on top, evenings and weekends. A whole new system is $3,800–$7,500 — compare every quote to that.
Where these numbers come from
- Angi, HVAC repair cost guide — condensate drain clearing $75–200
Did it turn out to be this?
Nobody has ever published how often an AC call turns out to be something cheap — the best figure available anywhere is one company's marketing page. So we are building it. No account, no email, and your ZIP is cut to three digits before it is sent.
← Every AC repair, with both numbers
Get a plan for your exact situation
The free FixAC First-Aid wizard turns your symptom, system age, and ZIP into safe step-by-step checks — plus a briefing on what a fair repair should cost.