Does an air conditioner need regassing? Refrigerant, leaks and EU rules

Updated September 1, 2026 · Claude AC · 2 sources cited

Contents (6)

What a genuine loss of charge looks like
Finding the leak, not just refilling it
What EU law actually requires
What it costs, and when a refill is money wasted
How to avoid the problem in the first place
Frequently asked questions

« It probably needs a regas » is the most repeated sentence in European air conditioning, and it is built on a false analogy. A car needs fuel because it burns it. An air conditioner does not burn refrigerant: the gas circulates in a sealed loop, changing state between liquid and vapour, and in a healthy machine the same charge stays in the circuit for the whole twenty-year life of the equipment. A unit that is low on refrigerant is not hungry. It is leaking, and the leak is the fault.

That distinction has consequences beyond pedantry. A refill without a repair releases the same gas twice and bills the customer twice, and it turns a diagnosable fault into an annual subscription.

What a genuine loss of charge looks like

Low refrigerant produces a characteristic pattern, not a generic « it is not cooling well ». The signature is a machine that still runs, still blows air, but has lost capacity gradually over weeks or seasons.

Symptom	Why low charge causes it
Cooling has faded over two or three summers	A slow flare-joint or coil leak loses grams per month, not kilos at once
Ice on the thin copper pipe or on part of the indoor coil	Less refrigerant means lower evaporating pressure, so the coil drops below 0 °C
The unit runs continuously without reaching the setpoint	Reduced capacity, so the compressor never catches up with the room
Weak temperature drop across the indoor unit	A healthy split typically pulls the outlet air well below the room air; a starved one barely does
An oily stain at a pipe joint or on the outdoor unit	Compressor oil travels with the refrigerant and marks the escape point

Crucially, most of these are also produced by problems that cost nothing to fix — a filthy filter, a blocked outdoor coil, a fan running slowly, furniture blocking the return air. That is why any competent visit checks airflow first. Our guide on an air conditioner that has stopped cooling works through the whole diagnostic order, and the maintenance guide covers the cleaning that prevents half of these calls.

Finding the leak, not just refilling it

A proper refrigerant intervention on a split has a shape, and you can ask for each step by name:

Measurement before anything else — pressures and temperatures at the service port, with superheat or subcooling calculated. « Low on gas » stated without those numbers is a guess.
Recovery — whatever charge remains is pumped into a recovery cylinder, never released. Deliberate venting of fluorinated gases is prohibited across the EU.
Leak location — nitrogen pressure test, electronic detector, or UV dye left in the oil for a slow leak that only shows itself after weeks.
Repair — a badly made flare joint is remade; a corroded coil is replaced. There is no chemical sealant that a serious refrigeration engineer will put into a domestic split.
Vacuum — the circuit is evacuated to remove air and moisture, then held to prove the repair is tight. Skipping the vacuum is the classic corner cut and it kills compressors.
Weighed recharge — the exact nameplate charge, plus the allowance per extra metre of pipe run, put in by weight from a scale. Not « by feel », not « until the pressure looks right ».

What EU law actually requires

Regulation (EU) 2024/573 governs fluorinated greenhouse gases across the Union, replacing the 2014 regime. Three of its provisions shape any refrigerant job on a household machine.

First, handling requires certification. Recovery, leak checking, installation, servicing and decommissioning of equipment containing F-gases may only be carried out by certified persons and undertakings. Second, bulk refrigerant may only be sold to and bought by certified undertakings — which is precisely why the cans of gas sold online for « DIY topping up » have no legitimate place near a European split, and why pre-charged split systems may be sold to consumers only where there is evidence that a certified installer will do the work. Third, deliberate release is banned, and holders of equipment must take precautions to prevent unintentional release and repair leaks without undue delay once detected.

The periodic leak-check obligation, on the other hand, is widely misquoted to homeowners. It applies from a charge threshold expressed in tonnes of CO2 equivalent — 5 tonnes for standard equipment — which almost no domestic split reaches:

Equipment	Typical charge	Refrigerant (GWP)	≈ tonnes CO2e
Single split, 2.5 kW bedroom unit	0.6–1.0 kg	R-32 (675)	0.4–0.7
Single split, 5 kW living room	1.2–1.7 kg	R-32 (675)	0.8–1.1
Older split on legacy gas	1.2–1.7 kg	R-410A (2 088)	2.5–3.6
Small multi-split, four rooms	2.5–4.0 kg	R-32 (675)	1.7–2.7
Light commercial system	8–15 kg	R-410A (2 088)	17–31 — mandatory checks

So a household split is normally below the statutory leak-check line, while a shop or office system sits well above it and carries logbook and inspection duties. Being below the threshold does not exempt anyone from the repair-the-leak and do-not-vent obligations — those apply to all equipment. The wider phase-down schedule, and what it means when buying new, is set out in our guide to the F-gas Regulation 2024/573.

What it costs, and when a refill is money wasted

Prices vary enormously across Europe and any figure here is indicative only, but the structure of the bill is consistent: a call-out and diagnostic charge, an hourly rate for leak location, the repair itself, then refrigerant billed by the kilo — with R-410A markedly dearer than R-32 because quota restriction has been squeezing supply for years. A remade flare joint with a weighed recharge is a modest half-day job. A pierced indoor coil or a corroded outdoor coil is a different order of expense, because the part often costs a meaningful fraction of a new machine.

That is where the arithmetic turns. On a unit past twelve or fifteen years old, still running R-22 or R-410A, a sealed-circuit repair buys a short future on a machine whose gas is getting scarcer each quota step and whose seasonal efficiency is far below what a current model delivers. The honest recommendation in that case is replacement, and our guide on air conditioner lifespan and replacement lays out the thresholds. On a five-year-old R-32 split, the same repair is straightforwardly worth doing.

How to avoid the problem in the first place

Most domestic leaks start at the flare connections made on site — a joint under- or over-torqued, a flare cut badly, a pipe stressed by being pulled straight. Hence the value of a documented pressure test and vacuum at commissioning, as covered in our guide on installing air conditioning yourself in Europe. After that it is mechanical protection: keep the pipe insulation intact, hang nothing on the pipework, and deal with compressor vibration rather than tolerating it.

Frequently asked questions

How often does an air conditioner need regassing?

Never, in normal operation. The refrigerant circuit is sealed and the charge should last the life of the equipment. Any service plan that includes a routine annual top-up is either selling something unnecessary or quietly refilling a leak it has not repaired. If a machine genuinely needs gas twice, the second visit should be about finding the leak, not adding more.

Can I top up my air conditioner myself with a can from the internet?

No. In the EU, bulk fluorinated refrigerants may only be sold to and handled by certified undertakings, and deliberate release is prohibited. Beyond the legal point, the practical one is decisive: charge is set by weight against the nameplate figure, after evacuation, and a circuit filled without a vacuum accumulates moisture that destroys the compressor from the inside.

Is ice on the pipes always a refrigerant problem?

No — restricted airflow causes the same icing, and it is far more common. A clogged filter, a dirty evaporator, a slow indoor fan or blocked vents all drop the coil below freezing. Switch the unit off, let the ice melt fully, clean the filters and try again. If it ices up again with clean filters and unobstructed airflow, then low charge or a faulty expansion device becomes the likely cause and needs measurement.

Does an air conditioner lose efficiency before it stops cooling?

Yes, and that is the expensive part of a slow leak. Capacity falls first, so the machine runs longer for the same result and the electricity bill rises quietly while the room still feels acceptable. If your consumption has crept up season after season with no change in habits, compare it against the figures in our guide to air conditioning running costs in Europe before assuming tariffs are to blame.

My installer says the system needs « a small top-up » after installation. Is that normal?

A genuine addition is normal in one case only: pipe runs longer than the pre-charged length, where the manufacturer specifies extra grams per additional metre. That is a documented, weighed addition made at commissioning, and it should appear on the paperwork with the quantity stated. A top-up requested weeks after installation, on a standard pipe run, points to a joint that was not made properly.