Can you get a boiler quote without a survey?

Yes, and plenty of people buy a boiler that way perfectly happily. You answer a handful of questions online, a fixed price comes back in a couple of minutes, and nobody sets foot in the house until the day of the job.

The useful thing to understand is what that price is built on. A no-survey quote is not a price for your house. It is a price for the house you described. That is not a criticism, it is just the mechanism, and once you see it the right questions become obvious.

What a web form cannot see

These are the things that most often move a boiler price, and none of them can be established from a dropdown menu.

• The flue route and where it terminates, including how close it sits to windows, doors and the boundary.
• The size of the gas pipe running from the meter outlet, and whether it can carry the new appliance.
• Where the condensate can run to, and whether it can reach a suitable drain without a long external run.
• Your mains water flow rate, which decides whether a given combi can deliver what you are expecting.
• The condition of the system water and whether anything is already blocked or sludged.
• What is actually behind the old appliance, which on older properties can mean a back boiler, a redundant flue or tiling that will not survive removal.

That does not make remote quoting wrong

For a like-for-like swap in a straightforward house, a good remote quote can be as accurate as a visit. The difference between a sound one and a guess is how hard the company works to close the gap before committing to a number.

The better ones ask for photographs of the boiler, the flue outside, the gas meter and the pipework around it. Some do a short video call. Some ask you to time how long it takes to fill a container at the kitchen tap, which is a rough flow rate check you can do yourself in a couple of minutes. All of that is the company trying to see the job. A form that asks how many bedrooms and radiators you have and nothing else is not.

The question to ask, and it is not "is the price fixed"

Almost every online quote is fixed. Fixed is easy to promise, because a fixed price only holds for the job as described. The question that actually matters is who carries it when a description turns out to be wrong.

Ask for the answer in writing, before you pay anything, to these three:

• What happens if the gas run has to be upgraded to feed the boiler you have quoted?
• What happens if the existing flue position does not comply and the flue has to move?
• What happens if my flow rate will not support the model you have quoted, and does the price change if I need a different one?

Then check what the price covers, not just what it is

Two fixed prices can be very different jobs. A no-survey quote is easier to make attractive by leaving things out, because nobody has looked at the things that would have been put in.

Look for the system clean and the corrosion inhibitor, an in-line filter, the flue kit, any electrical work, making good after the old unit comes out, and the removal and disposal of the old boiler. If any of those are missing, they have not gone away. They have just moved to the day of the job, when saying no is harder.

The measuring happens either way

Here is the part that is rarely spelled out. Whether or not anyone surveys your house first, the numbers get taken eventually, because they have to be.

When the boiler is commissioned, the installer completes the Benchmark checklist, which records the commissioning data and stands as evidence that the installation meets the Building Regulations. Gas Safe Register sets out the combustion checks that go with it. Manufacturers lean on the same document: Vaillant, for one, requires the Benchmark logbook to be completed at installation and kept on site as a condition of the guarantee.

So the gas rate, the combustion figures and the state of the system all get established on the day regardless. A survey does not create that work. It just moves it to before you have committed, which is the only point at which the answers can still change your mind.

Source: HHIC, Benchmark checklist for new boiler installations; Gas Safe Register, technical bulletin 143: CO and combustion ratio checks at commissioning; Vaillant, domestic boiler guarantee terms and conditions

A sensible way to use both

Use an online price for what it is good at. It is fast, it is free, and it tells you roughly where the market sits before you have spoken to anybody.

Then get at least one quote from an installer who has actually seen the job, and compare the two on scope rather than on the total. If the surveyed quote is higher, the interesting question is what it includes that the other one assumed. Sometimes the answer is nothing, and you can buy the cheaper one with confidence. Often the answer is the flue, the gas run or the system clean, and you have just found out for free.

Tell us about your home and we will arrange up to three quotes from vetted local installers who will look at the job properly. It costs nothing and commits you to nothing, and it gives you something solid to hold an online price against.