Most air conditioning failures are one of four things, and three of them are cheap. The expensive one is the compressor, and a system that has lost its compressor is usually a replacement decision rather than a repair. Knowing which of the four you are looking at is what separates a useful call out from an expensive diagnosis.
The four common failures a home AC repair finds
Low refrigerant from a leak, which shows as poor cooling that got worse gradually. Blocked airflow from filters or a dirty outdoor coil, which shows as poor cooling and a hard working system. A blocked condensate drain, which shows as water dripping from the indoor head. And electrical or control faults, which usually show as a system that will not start or cuts out. Only the last two are common as sudden failures.
How good firms repair air conditioners: the first visit
Reads the fault code, checks the filters and the outdoor coil, measures pressures and temperatures across the circuit, and inspects the condensate route, before ordering anything. Topping up refrigerant without finding out where it went is the classic bad repair: it works for a season, costs money, and puts the same gas back into the atmosphere the following year.
When emergency air conditioning repair is warranted
For a home, a failed system in a heatwave is uncomfortable rather than dangerous, and same day attendance is priced accordingly. Where the system is protecting something, a server cupboard, a medical need, stock in a shop, an emergency call out is a different calculation. It is worth agreeing response times in a service contract before the failure rather than negotiating during one.
Repair against replacement
A compressor failure outside warranty, a leak in a buried pipe run, or a system using a refrigerant that is being phased down and is now expensive are all points at which repair stops making sense. The test is the repair cost against a new system, adjusted for the fact that the rest of the old equipment is the same age as the part that just failed.
Questions people ask about air conditioning repair service
Why has my air conditioning stopped cooling but is still running?
Most often low refrigerant from a leak or restricted airflow from filters and a dirty outdoor coil. Both make the system run continuously and achieve little. Check and clean the filters first, because that is free, and if it does not improve, the system needs an engineer with gauges.
Why is water dripping from the indoor unit?
Almost always a blocked condensate drain or a failed condensate pump. The unit produces water whenever it cools, and if that water cannot leave it backs up into the tray and over the edge. It is a common, cheap fix and worth attending to quickly because of what the water lands on.
Can any engineer repair any make?
Broadly yes for diagnosis and refrigerant work, which is generic. Parts and warranty are not: manufacturers restrict some parts to their own accredited installers, and warranty work usually has to go through them. Ask before booking if the system is still in warranty.
Is a repair covered by the manufacturer warranty?
Only if the system was commissioned correctly, registered, and serviced at the stated interval. Those three conditions are why the commissioning sheet and the service record matter, and why a system installed without paperwork tends to have no warranty when it is finally needed.
Is an AC emergency repair worth the call-out premium?
It depends on who is in the building. For a household in a hot week it is usually cheaper to wait a day or two for a normal visit. For a server room, a shop with stock that has to stay cool, or somebody whose health depends on the room staying cool, the premium is the cheapest part of the day. Ask what the out of hours rate is before you need it, and whether the first visit is diagnosis only.