Air conditioning not cooling or blowing warm air? Work out why
Before you assume the worst: a decent share of the "not cooling" calls we take are settings, not faults. Work through this in order and you'll either fix it in five minutes or know exactly what to tell the engineer.
Check these first (five minutes, no tools)
- Mode: the snowflake symbol, not the sun, the droplet (dry) or the fan. Heat pumps default to heating in winter and people forget.
- Setpoint: below the current room temperature. Set it to 20°C to test.
- Fan speed: on auto or high, not the lowest setting.
- Filters: pull them out and look. Grey and furry means no airflow means no cooling.
- Outdoor unit: is the fan actually spinning? Is the isolator switched on? Has the breaker tripped?
- Windows and doors closed, and nothing sat in front of the indoor unit.
If the basics are fine, it's one of these
| Symptom | Likely fault | Typical repair |
|---|---|---|
| Cools weakly, ice on the pipes | Low refrigerant — you have a leak | £280 – £550 leak find, repair and recharge |
| Outdoor fan not turning | Failed fan motor or capacitor | £180 – £340 |
| Outdoor unit hums but won't start | Failed start capacitor | £140 – £220 |
| Cools then stops after 10 minutes | Overheating / high-pressure trip, often a blocked condenser | £110 – £180 clean |
| Nothing at all outdoors | Tripped supply, PCB or comms fault | £150 – £400 |
| Cools fine but the room never gets there | System undersized for the room | Resize or add a unit |
Low gas is the most common real fault
Refrigerant is a sealed charge — it isn't consumed. If a system that used to cool well no longer does, gas has escaped, usually at a flare joint made too tight or too loose at install. Simply topping it up is a false economy and is not permitted under F-Gas regulations without addressing the leak: pressure test with nitrogen, locate, repair, vacuum, then recharge to the manufacturer's weight.
This is the single strongest argument for a properly torqued, pressure-tested installation in the first place — and why we leave a nitrogen test record with every job.
When it isn't the unit, it's the sizing
A 2.5kW unit in a south-facing loft conversion with a full-height window will run flat out and never quite win. If your system holds a room at 24°C on a 30°C day but no lower, it's likely undersized rather than faulty. A survey with a proper heat-load calculation tells you in ten minutes — and it's why we measure glazing, orientation and insulation rather than quoting off room size alone.
Repair or replace?
Under 8 years old with a repairable fault: repair, every time. Over 12 years old with a failed compressor or a major leak on R22 or R410A: replacement usually makes more sense, and a new inverter system will use around 30–40% less electricity. We'll tell you honestly which side of the line you're on.
FAQ
Why is my air conditioning blowing warm air?
Most often it's set to heating or dry mode, but it can also be low refrigerant, a failed outdoor fan or capacitor, or a tripped outdoor supply.
Does air conditioning need regassing?
Not routinely. Refrigerant is sealed — if it's low, there's a leak that must be found and repaired rather than simply topped up.
How much does an AC repair cost in the West Midlands?
Most domestic repairs land between £140 and £400 depending on the part. A full leak find, repair and recharge is typically £280–£550.
Do you charge for a diagnostic visit?
We charge a fixed diagnostic fee and waive it if you go ahead with the repair, so you're never paying twice.
Ready for a real price on your home?
Free home survey, fixed written quote, F-Gas certified installers across the West Midlands. 60-second form or WhatsApp us a photo.