freon, R410A and R32: what a gas top-up actually means
Refrigerant is not fuel. It circulates in a sealed loop and is never consumed, so a unit that needs gas has a leak — full stop. The honest version of a regas visit: find the leak with a detector or nitrogen pressure test, repair it, pull a vacuum on the lines, then weigh in the exact charge printed on the nameplate. The dishonest version is a hose, a cylinder, and see-you-next-summer. If you have paid for top-ups two years running, you have paid twice for one unfixed leak.
The gas itself matters. Older UAE units run R22 — the gas everyone still calls freon — which is being phased out under the Montreal Protocol; imports are restricted and the shrinking supply gets pricier every year, so regassing an old R22 unit can cost a startling share of its remaining value. Most systems from the last decade use R410A, and newer machines increasingly use R32, more efficient but mildly flammable. The gases are not interchangeable: R410A runs at much higher pressures than R22, so you cannot refill an old system with new gas. When a technician says an ageing R22 unit with a leaking coil is not worth repairing, the arithmetic usually supports them.