Replacing your boiler might be a strategic move if you’re looking to lower energy costs and boost your home’s energy credentials. Or, you might need to replace your boiler out of necessity as the old one broke or failed!
In either case, modern boilers are highly efficient and will certainly lower your energy costs.
Older boilers can be as little as 60% efficient, whereas some highly efficient new boilers are as much as 95% efficient.
Replacing a boiler is a fairly lengthy process that can take several days for complex installations that involve rerouting plumbing. In most scenarios, however, it’ll only take a couple of days.
This is a guide to replacing or installing a new boiler.
What happens during a boiler installation?
Installing a new boiler may be as simple as swapping the old one out for the new one with minimal fitting required.
Alternatively, it might be as complex as fitting a new boiler, new plumbing and new water tank while removing a now-disused cold water feed in the attic (e.g. if switching from a traditional boiler to a system boiler).
It’s also common to fully revamp the heating system when undergoing a major boiler upgrade, which includes installing new radiators or even underfloor heating.
In any case, you’ll almost certainly need a Gas Safe engineer to perform the work and register the new boiler with both the gas register and the manufacturer. See our guide on who can install boilers for more information.
Here is the basic process:
1: The old boiler is removed
First things first, the installer will remove the old boiler. The engineer will shut off the gas and water supply and clear the area beforehand. Old boilers can often be recycled.
2: Flushing and cleaning
It’s often necessary to flush and clean the system with a chemical or powerflush. Cleaning the system at the same time as installing a new boiler makes sense. A clean system will bring the best out of a new boiler and prolong its life.
3: Upgrades to pipework and fittings
Modifying and upgrading the pipework entering/exiting the boiler may be necessary. Each boiler comes with its own best practice guidelines that the heating engineer will abide by.
Pipework upgrades can be tricky, and where pipes need to be dug out from screed, this will prolong the job and increase the installation cost. If the boiler is being relocated, the engineer will prepare the new location with pipework and fittings. Boiler relocations take significantly longer than swapping one for another in-situ and will also increase the installation cost.
4: Fitting the boiler
The boiler is fitted with flue, condensate, and other pipework and fittings.
5: Accessories
Boilers are often fitted with accessories such as system filters to prevent debris and sludge from entering the boiler. Boilers and manufacturers have different guidelines to follow here.
It may also be necessary to install new thermostats and timers. In addition, system and conventional boilers need hot water tanks - these may have to be upgraded to cater to the new boiler.
6: Testing
Once ready, the system is switched on and tested thoroughly. Next, the engineer will perform diagnostic tests and compare the results to the manufacturer’s guidelines.
7: Registration and handover
The boiler is registered with Gas Safe, and the controls are handed to the homeowner.
How much does a new boiler cost?
The boiler will cost anything between £750 or so for small combi boilers and more than £2,000 for larger boilers. In addition, system and conventional boilers have additional parts such as hot water tanks that cost extra (approx £200 to £500 or more).
Installation can cost anything from £250 to over £1000. It depends on the project and the scope of upgrades/replacements needed.
For example, an expensive project might involve replacing all radiators and all pipework and possibly even fitting underfloor heating. On the other hand, a cheap project might involve simply swapping one combi boiler for another.
- A new boiler typically costs £600 to £2,500, but some specialist or XL boilers might cost more.
- A new combi boiler costs £600 to £900 for a budget model, £900 to £1,200 for a mid-range model and £1,250 to £2,500 for a more powerful model.
- A new system boiler costs £600 to around £900 for a budget model, £900 to £1,300 for a mid-range model and £1,500 to £3,000 for a more powerful model. You’ll also have to factor in the water tank, which can cost around £500.
- A new conventional boiler costs £600 to around £900 for a budget model, £900 to £1,300 for a mid-range model and £1,300 to £2,750 for a more powerful model. You’ll also have to factor in the water tank, which can cost around £500.
How long will it take to install a new boiler?
Installing a new boiler takes anything between 6 hours for a simple swap to 4 days for projects that involve major upheaval of plumbing, water cylinders, etc.
Installation is easier if the new boiler is installed in the same place as the old one, whereas relocation will involve modifications to pipework which can be time-consuming. Moreover, if radiators and pipework need to be upgraded, the heating engineer will need help from other tradespeople.
This is common when renovating older homes and flats with new higher-pressure boilers, as the old pipework may not be able to handle the pressure.
Ask for advice
While some boiler installations are super-simple, others are long and convoluted. We will be able to assess your situation and come up with a plan to install your new boiler and heating system.
Don’t fear, though - most projects are simple! And once your new heating system is installed, it’s just a matter of maintaining it with regular services. A fresh, modern heating system should last many decades providing it’s well-maintained and serviced.
If you are looking for a new boiler, get a boiler quote today.
