Air Con Not Cold? Why It Stops Working in Summer — and What to Do

1 June 2026 · 5 min read

Why air conditioning loses its charge over winter

Air conditioning systems lose refrigerant over time — not because something is broken, but because the seals and o-rings in the system are designed to allow a very slow rate of permeation. A well-maintained system that has not been serviced in two years may have lost enough refrigerant to noticeably reduce cooling performance by summer.

Most drivers run the air con through the summer, then leave it switched off from October to April. When they turn it on in May or June and find it is blowing warm, the assumption is something has broken. In many cases, the system simply needs regassing — a straightforward job that takes around 45 minutes.

Regas vs full system check — what is the difference

A standard regas involves recovering any remaining refrigerant, pulling a vacuum on the system to check for leaks, and then refilling with the correct gas. If the vacuum holds, there is no significant leak and the regas is the right fix. If the system cannot hold a vacuum, there is a leak that needs locating and repairing before the gas will stay in.

Your car will use either R134a or R1234yf refrigerant — older vehicles use R134a, and most cars from 2017 onward use the newer R1234yf. These cannot be mixed and require separate handling equipment. We handle both at the Brierley Hill workshop and confirm which your car needs from the registration before we start.

Signs your air con needs attention before summer

If the air con is blowing cold but not as cold as it used to be, the system is likely low on charge. If it is blowing completely warm, the charge may be very low or there is a compressor or electrical issue. A musty smell when you first switch it on is a sign the cabin filter or evaporator needs attention — a separate job from regassing.

The best time to book an air con check is before the hottest weather arrives, when every garage is busy with the same jobs. If you are reading this in June and the system is already underperforming, call us on 07494 990846 and we will get you booked in as soon as possible.

Book air con regas in Brierley Hill →

Need help with your car?

Talk to the team at Nick and Stefan Motor Works in Brierley Hill — honest advice and a straightforward booking.

Call 07494 990846