Choosing a boiler installer comes down to a handful of checks: are they Gas Safe registered for boilers, or OFTEC registered for oil; will they survey the property before quoting; is the quote fixed and itemised; which manufacturer warranty can they offer; and will they be around next year to service it. Get clear answers to those and the choice is usually obvious. Get vague answers and the cheapest quote can become the most expensive boiler you ever buy.
A new boiler is a decision you live with for fifteen years or more, and the installation matters as much as the boiler. The same model fitted well and fitted badly will have very different lives. Here are the nine questions worth asking every installer you speak to, and what a good answer sounds like.
1. Are you Gas Safe registered, and for what?
For a gas boiler this is not optional. Ask for the engineer’s Gas Safe licence number and check it on the Gas Safe Register website. Look at the categories on the back of the card too: the engineer needs to be qualified for boilers, not just cookers or fires. For an oil boiler, ask for OFTEC registration and check it on the OFTEC website. Our guide on whether you can install your own boiler explains what the law requires.
2. Will you survey the house before quoting?
A quote from a photo and a phone call can be fine for a simple like-for-like swap, but anything more needs someone to look at the flue, the gas or oil supply, the water pressure, the pipework and the radiators. An installer who quotes without any of that is guessing, and guesses tend to turn into extras on the day.
3. Is the price fixed, and what does it include?
Ask for a written quote that names the boiler model, the controls, the flue, the magnetic filter, the system flush, the removal of the old boiler and the paperwork. Then ask whether the figure is fixed. A fixed price means the installer carries the risk of the unexpected, which is how it should be. A day rate plus materials means you do.
4. Which boiler are you recommending, and why?
A good installer explains the choice in terms of your house: the number of bathrooms, the hot water demand, the space available, the fuel. Be wary of an installer who only fits one brand because that is the one they get a bonus on, and equally wary of one who lets you pick anything without comment. Our guides on which boiler brand is most reliable and what boilers heating engineers recommend are a useful starting point.
5. What warranty comes with it?
Manufacturer warranties vary from two years to twelve, and the longest ones are only available through installers accredited by that manufacturer. Ask how long, what it covers, whether it includes parts and labour, and what conditions apply. Almost all require an annual service by a registered engineer, so ask about that too.
6. Will you flush the system?
Fitting a new boiler to a dirty system is the quickest way to wreck it and to void its warranty. Ask whether the quote includes a chemical clean or a power flush, and how the installer decides which is needed. If the answer is a blank look, move on.
7. Who does the paperwork?
The installer should complete the Benchmark commissioning checklist in the manual, register the warranty with the manufacturer and notify the installation so you receive a Building Regulations compliance certificate from Gas Safe or OFTEC. Ask them to confirm all three. Our guide to the boiler installation certificate explains why each one matters.
8. What happens if something goes wrong afterwards?
Ask who you call, how quickly they come, and whether they offer servicing and repairs as well as installations. An installer who will be around for the annual service, and who answers the phone in January, is worth more than a saving on the day.
9. Can I see recent reviews and speak to a customer?
Read the reviews, but read them properly. Look for detail about the work rather than a row of five stars with no words, look at how the company responds to the occasional bad one, and ask whether you can speak to a customer who had a similar job done. A local firm with years of local reviews is a different proposition from a lead-generation website that sells your details to whoever bids highest.
Warning signs
- pressure to sign on the day, or a discount that only lasts until tomorrow
- no registration number offered, or one that does not check out
- a quote with no boiler model or no mention of a flush
- a large cash deposit requested before a survey
- no landline, no address, no reviews older than a few months
How DCI Boilers can help
DCI Boilers is Gas Safe and OFTEC registered, based near Saltash and working across Cornwall and Devon. We survey every job, quote a fixed price, flush every system, fit manufacturer warranties of up to 12 years and service what we install. Read about our gas boiler replacement and oil boiler replacement services, and ask us any of the nine questions above. We would expect nothing less.
Need help now? Call DCI Boilers on 07888 862 603 or get a free quote.
Frequently asked questions
How many quotes should I get for a new boiler?
Two or three from installers who have surveyed the house. More than that and the quotes stop being comparable, because each installer specifies the job slightly differently.
Is the cheapest boiler quote a bad sign?
Not automatically, but check what has been left out. The usual omissions are the flush, the filter, the controls and the removal of the old boiler.
Should I use a big national company or a local installer?
Both can do good work. A local firm typically offers the same boilers and warranties with a named engineer who comes back for the service, and a shorter wait when something needs attention.
How do I check a Gas Safe registration?
Ask for the licence number and enter it on the Gas Safe Register website, or scan the QR code on the card. Check the boiler category is listed on the back.