How Much Does a New Oil Boiler Cost?


We at Add Heat install more than 500 boilers of all kinds every year, and we have a good sense of what you should be paying in different circumstances. Because we are asked questions like ‘How much does a new oil boiler cost’ quite frequently, we’ve put together this guide which will help you find the answer to the real question – ‘How much should I be paying for an oil boiler that does everything I need it to do?’

The short answer

The biggest factors affecting oil boiler cost are probably boiler size and manufacturer quality. Assuming an average home size and a good quality boiler, you’d expect to pay somewhere between £2500 and £3800 for an internal, heat-only oil boiler and between £3400 and £4500 for an internal combi boiler. Note, though, that if your cylinder needs to be replaced the price would go up. Other factors affecting the price include whether the oil boiler is internal or external – expect to pay an additional £300 to £400 for an external oil boiler – and an extra £500 – £600 if the new boiler is being installed in a different spot than where the old boiler was installed.

The long answer

In reality, you have a lot of options. You can get a very small heat only oil boiler from a less prestigious manufacturer for as little as £1150, while larger units from the best manufacturers may cost £2800 or more. Oil combi boilers are more expensive at the low end, with prices running from as low as £2000 and going up to around £2600.

The cost of the actual oil boiler aside, the largest variables all fall under the heading of ‘installation costs’. Here we’ve listed the most common installation expenses, and what you can expect to pay if they apply to your boiler and situation.

Oil Boiler Installation Costs

This table gives you an estimate of the costs for installing a new oil boiler in different scenarios. The total cost listed will include:

  • The cost of the boiler (a middle of the road unit in terms of size and quality)
  • A standard flue
  • Powerflush cleansing of your heating system
  • A standard thermostat and control system
  • Installation of a new condensate pipe
  • A new magnetic filter
  • Labour / installer time
  • VAT

If any building works are required, they should be added to the price you can expect to pay.

Combi Oil Boiler Cost Estimates (Internal Oil Boilers)

  • Provision of a combi oil boiler and installation in the same location where the old boiler was installed: £3800
  • Provision of a combi oil boiler and installation in a new location: £4400

Combi Oil Boiler Cost Estimates (External Oil Boilers)

  • Provision of a combi oil boiler and installation in the same location where the old boiler was installed: £4200
  • Provision of a combi oil boiler and installation in a new location: £4800
  • Provision of a combi oil boiler and installation in a new location, and installing a new base: £4900

Heat Only Oil Boiler Cost Estimates (Internal Oil Boilers)

  • Provision of a heat only oil boiler and installation in the same location where the old boiler was installed: £3100
  • Provision of a combi oil boiler and installation in a new location: £3700

Heat Only Oil Boiler Cost Estimates (External Oil Boilers)

  • Provision of a heat only oil boiler and installation in the same location where the old boiler was installed: £3300
  • Provision of a heat only oil boiler and installation in a new location: £3900
  • Provision of a heat only oil boiler and installation in a new location, and installing a new base: £4000

Replacing Heat Only Oil Boiler with Combi Oil Boiler Cost Estimates (Internal Oil Boilers)

  • Provision of a combi oil boiler and installation in the same location where the old boiler was installed: £3600
  • Provision of a combi oil boiler and installation in a new location: £4200

Replacing Heat Only Oil Boiler with Combi Oil Boiler Cost Estimates (External Oil Boilers)

  • Provision of a heat only oil boiler and installation in the same location where the old boiler was installed, with a new base: £4700
  • Provision of a heat only oil boiler and installation in a new location, with a new base: £4500

Other cost factors for new oil boiler installations

In some circumstances, you may need any of a range of non-standard components. Things like external fire valves, longer flues and oil filters can increase your final costs. The table below explains what these components are, and what you can expect to pay if they prove necessary.

Vertical Balanced Flue Extension £90
Replaces or extends your flue

Plume Management Kit £150 plus £60 per additional metre
Keeps steam and other oil boiler emissions away from windows, drives, etc

Flexible Liner Kit £400
Required to run flue into an existing brick chimney breast

Tiger Loop £200 (for twin pipes)
Prevents boiler lock-out by keeping oil supply to the burner constant

Fire Valve £80 to £120
Cuts off oil supply if the boiler temperature gets too hot

Oil Filter £80
Prevents debris and impurities in the oil from reaching the boiler

Oil Watchman £120
Sounds an alarm in case of oil overfill

Something else to consider – do you really need to replace your oil boiler?

Eventually, all oil boilers reach a point where their performance has degraded so much that it is less expensive to replace them than to repair them. This is also an opportunity to upgrade your oil boiler, adding new features or extra capacity for a larger home or a growing family.

It might be time to replace your oil boiler if:

  • Your current boiler is more than 10 years old
  • Your heating bills have been rising due to inefficiency
  • Your boiler or heating system is making unusual sounds
  • Your boiler seems to be needing repairs more and more often
  • Replacement parts for that model are becoming difficult to find
  • It simply isn’t doing a good job heating your home

Remember that all of these prices are approximate. We’d be happy to discuss your current boiler situation in detail, and give you a more precise estimate. Call us now or email us to get started!

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