✓ AR Heating & Gas. Servicing the North East for over 16 years.
Help 0191 540 2051
Sooting or fumes from a gas fire or back boiler? Stop using it. Smell gas? Call 0800 111 999. For advice on replacing a back boiler, call 0191 540 2051

Back Boiler Replacement in the North East

Still heating the house from a boiler hidden behind the gas fire? You are far from alone in the North East, but most back boilers are now well past their best. We take out the back boiler and fire, clear the tanks if you are going to a combi, fit a new boiler in a better spot and make the fireplace safe. New boilers start from £1,790 fitted, and your fixed price comes after a survey or through our online quote tool.
Get my fixed price
AR Heating & Gas
Online
Or call 0191 540 2051

What is a back boiler?

A back boiler is a gas boiler built into the fireplace, sitting behind a gas fire. The fire is what you see in the living room. The boiler is the box behind it, tucked into the chimney opening, and it heats your radiators and usually a hot water cylinder upstairs. The cylinder is fed by one or two cold water tanks in the loft.

They were fitted in huge numbers in older terraces and council houses right across the North East, and many are still running decades later. If you have a gas fire with a control panel hidden behind a flap at the bottom, a cylinder in the airing cupboard and no boiler anywhere else in the house, you almost certainly have one.

Price up a replacement
Modern combi boiler that replaces an old back boiler and gas fire

Why people replace their back boiler

A back boiler that still lights can feel like it has plenty of life left. Here is why most owners end up replacing it anyway.

Age

Back boilers stopped being fitted as standard a long time ago, so any one still working is old. Seals, valves and the heat exchanger all wear, and when something major goes, there is often nothing sensible left to repair.

Efficiency

Back boilers are not condensing boilers. A lot of the heat from the gas you pay for goes straight up the chimney. A modern condensing boiler recovers much of that heat, so the same warmth costs you less gas.

Parts

Parts for many back boiler models are hard to find or no longer made. A fault that would be a routine fix on a modern boiler can leave you without heating while someone hunts for a part that may not exist.

Safety

A back boiler relies on the chimney to carry fumes away. If the chimney or flue is blocked, damaged or poorly sealed, fumes can come back into the room. That is why an annual check matters so much on these appliances, and why many people decide to take them out rather than keep nursing them along.

Stop using it if you see these signs. Black soot marks on or above the gas fire, a lazy yellow or orange flame instead of a crisp blue one, a strange smell when it is on, or headaches, drowsiness or sickness that ease when you leave the room can all point to fumes spilling back. Turn the fire and boiler off, open the windows and call us on 0191 540 2051. If you smell gas, leave the house and call the National Gas Emergency line on 0800 111 999. A working carbon monoxide alarm in the room is essential.

Engineer removing an old back boiler and fitting a new boiler

What replacing a back boiler involves

Most people swap a back boiler for a combi. A combi heats water straight from the mains, so the cylinder and the loft tanks can come out as well. If your home needs stored hot water, for example with two bathrooms, we fit a system boiler and a new cylinder instead.

  • Removing the old kit. The gas fire and back boiler come out of the fireplace, and the gas and water feeds are capped safely.
  • Cylinder and tanks. Going to a combi, the hot water cylinder and the loft tanks are drained and taken away, which frees up the airing cupboard.
  • A new position and flue. The new boiler usually goes in the kitchen or a bedroom cupboard, with a flue through an outside wall and a proper condensate route.
  • Pipework. New pipes join the boiler to the heating circuit, the gas supply and the mains water. The gas pipe often needs upsizing for a modern boiler.
  • A system clean. Old back boiler systems are often full of sludge. We clean the system and fit a magnetic filter, and where it is badly blocked we recommend a power flush.
  • Making good the fireplace. We leave the opening safe and tidy. We agree at the survey exactly what making good covers, so you know if anything is left for a plasterer or decorator.
Get my fixed price

How long it takes

A straight combi swap is usually a one day job. A back boiler conversion is more work, so plan for longer. Often it is around two days, but it depends on how far the new boiler is from the old one, how the pipes can be routed and what we find in the loft. We will tell you our honest estimate after the survey, before you book. You will be without heating and hot water for some of that time, so we will talk through timing with you, especially in winter.

What it costs

New boilers from us start at £1,790 fitted. A back boiler conversion usually costs more than a like for like swap, because there is simply more to do: the fire and back boiler to remove, often a cylinder and tanks, a new flue position, extra pipework and making good. Rather than guess, we give you one fixed price, either after a free survey or through the online quote tool. That price does not change on the day.

Finance is available through Ideal4Finance, subject to status, and the boilers we fit come with manufacturer warranties of up to 12 years depending on the model. Our new boiler cost guide explains everything else that moves the price.

Things we check before we price it

A back boiler job is only as good as the survey behind it.

🚿
Mains water flow
A combi needs a decent flow and pressure from the mains. We measure it rather than assume.
🔥
Gas pipe size
Old back boiler pipework is often too small for a modern boiler and may need upsizing.
📍
Where the boiler goes
We look for a spot with a legal flue route and an easy condensate run.
🏠
Bathrooms in use
Two showers at once may mean a system boiler and cylinder rather than a combi.
🧹
System condition
Sludge from decades of running on an open system decides how much cleaning is needed.
🧱
The fireplace
We agree how the opening will be left and whether you want a gas fire back in later.

Areas we cover for back boiler replacement

We are based in Houghton le Spring and replace back boilers across Sunderland, Seaham, Newcastle, Chester le Street and the rest of the North East. For local detail on new boilers in your town, see new boilers in Sunderland, new boilers in Newcastle, new boilers in Chester le Street, new boilers in Durham and new boilers in Houghton le Spring. Not sure we reach you? Check the areas we cover.

An old open system needs a proper clean

Back boiler systems have usually run for years on a vented circuit with a loft tank, and the sludge shows it. A power flush before or during the install protects your new boiler and its warranty.

About power flushing

Heating Advice & Guides

More reading before you replace your boiler.

Paying for a new boiler monthly, how it actually works Guides
September 17, 2026
Paying for a new boiler monthly, how it actually works
What to ask before you agree to pay for a boiler in instalments, and why the price should always come before the mont...
+
Hard Water in Sunderland and What It Does to Your Boiler Boiler Problems
September 14, 2026
Hard Water in Sunderland and What It Does to Your Boiler
Most of the North East drinks soft water. Sunderland does not, quite, and your boiler knows the difference.
+
Nine Reasons Boilers Fail in Winter in the North East Boiler Problems
September 13, 2026
Nine Reasons Boilers Fail in Winter in the North East
The same nine faults, every year, in roughly the same order. Here is the list and what stops each one.
+
View All Posts

Back boiler replacement questions

Plain answers about taking out a back boiler and what replaces it.

Can a back boiler be replaced with a combi? +
Usually, yes. The fire, back boiler, cylinder and loft tanks come out and a combi goes in, often in the kitchen. The survey checks your mains water flow and gas pipe size to make sure a combi will perform properly.
How do I know if I have a back boiler? +
If your heating is controlled from behind a flap at the bottom of the gas fire, you have a hot water cylinder upstairs and there is no boiler on any wall in the house, it is almost certainly a back boiler.
How much does a back boiler replacement cost? +
New boilers start at £1,790 fitted, but a back boiler conversion usually costs more than a like for like swap because of the extra work. We give you a fixed price after a free survey or through the online quote tool.
How long does it take? +
Longer than a straight swap, often around two days, depending on where the new boiler goes and how the pipework runs. We give you our estimate before you book.
Can I keep a gas fire in the fireplace? +
Yes, if you want one. The back boiler comes out either way, but a new gas fire can be fitted in the fireplace as a separate job. Mention it at the survey so we can plan for it.
What happens to the fireplace and chimney? +
The old fire and boiler are removed and the gas is capped safely. We agree at the survey how the opening will be left, so you know if anything remains for a plasterer or decorator.
My gas fire has soot marks. What should I do? +
Stop using the fire and the back boiler, open the windows and call us. Soot, a yellow flame or symptoms like headaches can mean fumes are spilling into the room. If you smell gas, call 0800 111 999.
Do I need a power flush as well? +
Not always, but old back boiler systems are often badly sludged. We clean every system we fit a boiler to, and if yours needs a full power flush we will tell you and include it in your price.

Related pages

✓ Tell us about your back boiler and your home and see a fixed price for replacing it. No obligation. Get a quote now
Get a call back now