Three quotes come back for the same living room installation. Two sit within a hundred pounds of each other. The third is hundreds cheaper, and it is tempting, because the box on the wall will look identical whoever fits it. Before you accept it, ask the third firm a single question: who on the job holds the F-Gas certificate?
The law that sits inside every split system
Split air conditioning runs on fluorinated refrigerant gases, and in the UK it is a legal requirement that anyone installing, servicing or decommissioning equipment containing them holds F-Gas certification. This is not a trade body badge or a voluntary kitemark. It is the law, and it exists because these gases are potent contributors to global warming when they escape. Connecting the pipework, pressure testing, evacuating the lines and charging the system with refrigerant are precisely the tasks the certification covers. A person without it is not legally allowed to carry them out. Which means the very cheap quote from an uncertified fitter is not a bargain version of the same job. It is a quote for work that cannot lawfully be done.
How the cheap job goes wrong
Set the law aside for a moment and the practical picture is just as bad. Poorly made connections leak refrigerant, and a system that has lost gas cools badly, strains its compressor and eventually fails. Manufacturers routinely refuse warranty claims on equipment that was not installed by certified engineers, so the machine you saved money on carries no meaningful cover. And when it does fail, the certified engineer you call to rescue it starts by charging you to undo the first installation. People who take the cheap quote often end up paying for the job twice, with a summer of poor cooling in between.
Checking takes two minutes
Legitimate firms are certified through schemes such as REFCOM and will tell you their registration without being chased, because they paid for the training and are glad to be asked. So ask every firm that quotes: are you F-Gas certified, and under which scheme? Then ask for the number and check it with the scheme if you want belt and braces. A firm that hesitates, changes the subject, or says the rules only apply to big commercial jobs has answered your question, just not in the way they intended.
Every firm among the 996 air conditioning companies listed on this site can be asked that question, and the good ones will answer it before you finish asking. Compare certified companies working in your area, or put your job out for quotes and make the certificate the first line of your enquiry. The cheapest lawful quote is a good deal. The cheapest quote of all sometimes is not lawful, and that is the whole difference.
