What a new boiler costs, and what moves the price

What moves the price

• TypeA combi is the cheapest to fit because there is no cylinder. A system boiler adds the unvented cylinder; a regular boiler may need new tanks as well.
• OutputA small flat needs a smaller boiler than a four-bedroom house with two bathrooms. Bigger outputs cost more. Oversizing wastes money twice, on the boiler and on the gas.
• Staying put or movingLike for like, in the same place with the same flue route, is the cheapest job. Moving the boiler to a garage or a loft means new pipework, a new flue and often a condensate pump.
• Changing typeGoing from a regular boiler to a combi means removing the cylinder and tanks and rerouting pipework. From a combi to a system boiler means finding room for a cylinder.
• The system it joinsOld, sludged pipework has to be cleaned before a new boiler goes on it, or the warranty is at risk. A power flush or chemical clean adds to the job.
• Make and warrantyLonger warranties usually come with the dearer models, and only when the boiler is serviced every year. Ian is a Worcester Bosch Accredited Installer, which brings the extended Worcester warranty, up to 12 years on some models. He fits other makes on request.

What should be included

When comparing quotes, check each one covers the same things. A cheap quote that leaves these out is not cheap.

• The boiler itself, and the flue.
• Removing and disposing of the old boiler, and any cylinder or tanks that are coming out.
• A magnetic filter on the return, which most manufacturers require for the full warranty.
• Cleaning the system and dosing it with inhibitor.
• Controls: a room thermostat and programmer, or a smart thermostat. Since 2018 a new combi in England has to include an energy saving measure such as a smart control.
• Commissioning, the Benchmark record, notifying Gas Safe and registering the warranty.

Ian's quotes include all of this as standard: the boiler and flue, the old one taken away, a magnetic filter, a system clean with inhibitor, the controls, and the commissioning and registration. A like for like swap is normally done in a day.

How Ian quotes

1. Visit

   Ian looks at the boiler, the flue, the pipework, the radiators and how you use hot water. He measures the mains pressure.

2. Type and size

   He says which type suits the house and what output it needs, and why. The three types are explained here.

3. The price

   A written quote for the boiler, the fitting and everything listed above, so you can set it against any other quote and know you are comparing the same job.

4. Repair as well

   If the old boiler can be repaired, he gives that price too, so you can choose.

Payment is by bank transfer: 50% on booking, which covers the boiler and materials, and the balance once the boiler is commissioned and you are happy with it.

Is it worth replacing yet?

A well serviced gas boiler is commonly expected to last 10 to 15 years. Once repairs start costing a large share of a new boiler, or parts are no longer made for it, replacing it is usually the better spend. An old non-condensing boiler also wastes a large share of the gas it burns, so the new one costs less to run.

If the boiler is younger than that and the fault is a single part, a repair is nearly always the right answer, and Ian will say so.

Questions