Guide
HVAC repair: who may legally do it, and when maintenance is cheaper
Updated
Searching for HVAC repair usually means something has already stopped working. Two things are worth knowing before you call: not everybody is allowed to open the system, and a repair on a leaking unit is often the more expensive of the two options.
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If it contains F gas, the engineer must be certificated
Most air conditioning and refrigeration equipment uses fluorinated greenhouse gases, and working on it is a regulated activity rather than general trade work. Gov.uk publishes both requirements separately: the individual needs the relevant qualification to work on equipment containing F gas (gov.uk), and the business employing them needs company certification (gov.uk).
Both, not either. An engineer with a personal qualification working for an uncertificated company does not satisfy the requirement, and it is the operator of the equipment who carries the compliance risk, not only the contractor.
Leak checking is on a statutory clock, by size
Frequency is set by the charge expressed as tonnes of CO2 equivalent, not by the age or type of the unit. Gov.uk sets it out directly (gov.uk):
| Charge (tonnes CO2 equivalent) | Minimum leak check frequency |
|---|---|
| 5 to less than 50 | At least once every 12 months |
| 50 to less than 500 | At least once every 6 months |
| 500 or more | At least every 3 months |
Where an automatic leak detection system is fitted, the guidance allows operators to "double the period of time allowed between leak checks", so equipment in the first band moves from annual to every two years. Below 5 tonnes CO2 equivalent the scheduled checking requirement does not bite.
Why a repair quote and a maintenance quote are not comparable
A repair is priced against a fault that has already happened. A maintenance contract is priced against the checks that are due anyway, and on equipment above the threshold those checks are a legal obligation rather than a service upsell. Comparing the two as though they were alternatives overstates the saving from declining the contract, because part of the contract is work you are required to have done.
- Refrigerant loss is the tell. A system low on gas has a leak. Topping it up without finding the leak treats the symptom, and on regulated equipment it is not a compliant response.
- Repeat call-outs cost more than the interval. Two emergency visits in a year usually exceed the annual contract that would have included the statutory check.
- Age changes the calculation. Where refrigerant for an older system is being phased down, the availability and price of the gas can decide replacement over repair independently of the fault.
- Access and downtime are real costs. Out-of-hours attendance on a failed system in occupied premises is priced differently from a planned visit.
Why this page publishes no repair prices
No official source publishes HVAC repair rates, and the spread between a filter and a compressor on the same unit is larger than any average would survive. What is above is the part that is fixed by regulation: who is allowed to do the work, and how often the equipment must be checked. Those determine more of a real quote than a headline hourly rate does.
Two questions to ask whoever attends
- What is your company certification, and what is the engineer's qualification? Both are required and both are documents.
- What is the charge of this system in tonnes of CO2 equivalent? That single number tells you which leak check band you are in, and therefore what you are obliged to do next year whether or not you take a contract.