Air con is one of those things you don’t really notice getting worse. There’s usually no warning light, strange noise or obvious failure - it just gets a little less effective each summer. Then one warm afternoon on the A11, you realise the windows are down, and the air con isn’t really doing much at all.

Here's what's actually going on, and what a proper regas involves.

Air con not cold? You probably need a regas

Every air con system loses a small amount of gas each year through its seals and hoses, and, of course, through general use. That's normal, not a fault.

You won't notice the first year or two. By year four or five, there isn't enough left to cool properly, and that's usually when people call us.

A regas puts it back to the correct amount. It isn't a repair; it's routine maintenance.

There's one more reason not to leave it. The gas carries the oil that keeps the compressor running. Let it get too low, and the compressor can wear out, and that's a much bigger bill than a regas.

What a regas actually involves

There's a difference between a regas and a top-up, and it's worth knowing which one you're being sold.

The machine in the photo is a Twin Pro, and it handles both refrigerant types. R134a covers older vehicles. R1234yf came in with EU regulations and is fitted to most cars built from around 2017 onwards. They are not interchangeable; they need separate equipment, and plenty of garages still only have the kit for one of them. If your car takes R1234yf and you've been told "we can't do yours", that's why.

A proper job runs in four stages:

1. Recover. The existing refrigerant and oil are drawn out and weighed. That figure is diagnostic in itself, so we would already know we're looking for a leak rather than just filling it up.
2. Vacuum and hold. The system is pulled down to a deep vacuum, which boils off any moisture that's got in, then left to stand. If the vacuum decays, the system is leaking, and we stop there and tell you.
3. Recharge. The exact weight of refrigerant specified for your vehicle is re-gassed or recharged.
4. Test. High and low side pressures are checked against spec to ensure the new refrigerant is holding (Although we've already tested it for leaks, it's a good sanity check once it's full), and then we measure the temperatures from your vents. A healthy system should be putting out somewhere around 4 to 8 degrees at the centre vents.

If it won't hold vacuum, we won't charge you for gas that's going to end up in the atmosphere. We'll show you the reading and talk through what's involved in finding the leak. Nine times out of ten around here it's a condenser, which sits right at the front of the car behind the grille and spends its life being sandblasted by grit off the A134.

If it smells, that's a different job

A damp, gym-bag smell for the first thirty seconds after switch-on isn't a refrigerant problem. Condensation collects on the evaporator behind the dashboard, and given a few years it grows a fairly unpleasant film of bacteria and mould.

An anti-bacterial treatment clears it, and it's worth pairing with a pollen filter change since a clogged filter restricts airflow across the evaporator and makes the whole thing worse. Both are easy while the car is already with us.

The best thing you can do costs nothing

The most common cause of an expensive air con repair isn't a leak. It's six months of not switching it on.

When the system sits idle, the compressor seals can dry out and shrink, and that's when the gas escapes in earnest. Ten minutes a week through the winter keeps the oil and refrigerant circulating and the seals oiled and swollen. It also dries the air.

Need an Air con regas in Thetford, Brandon, Bury St Edmunds and surrounding areas?

We're on the Gorse Industrial Estate at Barnham, a few minutes outside Thetford, and we've been looking after cars from this corner of Norfolk and Suffolk for over 35 years. Customers come to us from Brandon, Elveden, Mundford, Lakenheath, East Harling and Bury St Edmunds.

A regas takes about an hour, so most people have a coffee and wait. If that doesn't work around your day, we offer free local collection and delivery and courtesy cars, subject to availability.

Tell us your registration when you call, and we'll confirm which refrigerant your car takes and what the job costs before you commit to anything.

Book an air con regas: 01842 890304 or info@gorsemotors.co.uk

Frequently asked questions

Is an air con recharge the same as a regas?

Yes. Same job, different name. Some people also call it an air con top-up or an air con service.

How often should air conditioning be regassed?

Every two to three years is the general guidance, though it depends on the vehicle and how much the system gets used. If it isn't as cold as it used to be, it's already overdue.

Is air con checked in the MOT?

No. Air conditioning forms no part of the MOT test, which is why so many cars pass every year with a system that hasn't worked properly since 2019.

What does an air con regas cost?

It depends on which refrigerant your car uses. R1234yf costs considerably more per kilo than R134a, so a newer car is a dearer job through no fault of anyone's. Give us your registration, and we'll tell you which you've got and quote you before you book.

My air con blows cold and then goes warm again. Is it low on gas?

It might be, but it can also be a blocked condenser, a failing pressure switch, a tired compressor clutch, or an electrical fault. Cycling from cold to warm often points at pressure rather than volume, so we'd put gauges on it rather than guess.

Can you regas a hybrid or an electric car?

Yes. EV and hybrid systems use an electrically driven compressor and a specific non-conductive oil, and getting that wrong is a serious mistake rather than an inconvenient one. On a lot of EVs the same circuit also cools the battery pack, so it's worth keeping healthy for more than comfort.