Said It Here

Why does my AC stop working at night?

Outdoor AC units often shut down entirely during the night and blow hot or room-temperature air, leaving the house to heat up even when parts like capacitors have been replaced and drain lines flushed. Because technicians frequently cannot diagnose the issue, homeowners are left repeatedly resetting their breakers just to get normal cooling back.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    Had the capacitor changed
  2. 2
    Flushed drain lines
  3. 3
    Called technicians out for service
  4. 4
    Manually turning the indoor and outdoor unit circuit breakers off and back on to power cycle the system.

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/hvacadvice2 people · September 2026

“it will cut on during the day but at some point at night it stops working entirely and shuts off causing it to just blow hot air heating the house up.”source ↗

“I’ve had the capacitor changed, drain lines flushed, and no matter what it still does it an no one can seem to figure out what’s wrong.”source ↗

MissionScreen8130 · r/hvacadvice · 1 upvotes

“My AC stopped cooling today, this makes the third time in 4 months that it has done this.”source ↗

“The indoor blower fan was running and blowing room-temperature air, the thermostat had no error codes, and I’m not sure if the outdoor unit was running or not.”source ↗

“I shut off the breakers to both the indoor air handler and the outdoor condenser for 10 seconds and then turned them back on, and cold air started working completely normal again after a few minutes.”source ↗

KodiakBlackIsBack · r/hvacadvice · 1 upvotes

Where this came up

r/hvacadviceair conditioningappliance repairhome maintenancehvac

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