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How to choose a water heater installer

The cheapest quote is not automatically the best one, and the most expensive is not automatically thorough. Here is how to tell the difference, whether or not you ever use us to find someone.

Before you sign anything

Four checks worth doing

Check the licence yourself

California licensed contractors must include their licence number in advertising. Do not take it from their website. Look it up on the CSLB site, confirm the status is active, confirm the classification covers this work, and confirm the name matches who is actually turning up.

Ask how many they have installed

Specifically of the thing you are buying, in the last year. A general plumber who does two tankless conversions a year is a different proposition from one who does two a week. This matters far more for tankless and heat pump work than for a like for like tank swap.

Get the quote in writing, itemised

Unit, labour, permit, haul away, and every upgrade line separately. A single number with no breakdown cannot be compared against anything, and it is where surprise charges hide.

Find out who services it afterwards

The installer, the manufacturer, or a third party. Ask before you buy, because the answer determines what happens the first time it throws an error code.

Source: California Contractors State License Board guidance on licence verification and advertising requirementsChecked 7 Aug 2026
Comparing quotes

Why the cheapest number is often the incomplete one

Two quotes for the same job can differ by thousands, and it is usually not margin. It is what one of them has left out.

On a conversion, the lines that move the total are rarely the appliance. Gas line capacity, venting, a dedicated electrical circuit, condensate routing and the permit are where the money is, and a quote that omits them is not cheaper. It is unfinished.

When you compare two numbers, the useful question is not which is lower. It is what is in each one that is not in the other. Ask the cheaper contractor directly what they have assumed about your gas line and your venting. The answer tells you whether the price is real.

Questions worth asking every contractor

  • Is the permit included, and will you schedule the inspection?
  • What have you assumed about my gas line, and did you look at it?
  • What venting does this need, and is the whole run in this price?
  • Does it need a dedicated circuit, and who runs it?
  • Is haul away of the old unit included?
  • What is the warranty on parts, and separately on your labour?
  • Who do I call in two years when something goes wrong?
  • Would you put this system in your own house? Why?

On manufacturer certifications

Brands run contractor programmes, and being in one can genuinely mean better training and better warranty support. But the status changes, tiers differ, and plenty of excellent installers are in no programme at all.

If a contractor says they are authorised or certified for a brand, ask which programme and check it in the manufacturer’s own directory. We apply the same rule to ourselves and never describe an installer that way unless we have verified it.

Know these before you call anybody

Asking three companies to quote three different systems produces three numbers you cannot compare. The reading below is what makes a quote readable, and each page takes a few minutes.

Before you collect quotes

Give three contractors the same question

The quiz gives you the technology, a size direction, a cost range and the options your house rules out. Take that to a quote and the numbers you get back are comparable.

How we choose who to introduce covers the conflicts policy and who gets paid what.

Work out what you need first