The average home in the U.K. spends $500-3,500 on new boilers depending on boiler type and other factors. When you throw in boiler installation costs, the numbers get a nice little boost to $1,500-$4,000.1
But averages aren’t very specific numbers. A more useful question to research might be, how much is a new boiler for my home?
When installing a new boiler, match its size to your house’s size. If the boiler is an energy powerhouse heating a tiny house, you’re burning more fuel than needed, increasing your carbon emissions and costs.
And if your home is too large and you install a smaller-sized boiler, it’d have to really exert itself to keep up with your energy needs.
The typical UK household needs a 30-kilowatt combi boiler.2 That said, the right size boiler for your house depends on your home’s size and what your hot water demands look like. The more bathrooms, radiators, and occupants, the more powerful the new boiler should be.
The following combi boiler/home size chart should give you a clear idea of what size would be ideal for your living situation. This boiler cost guide relates to combi boilers since they’re the most common type in the UK.
Number of Bathrooms
Number of radiators
Ideal Boiler Size in kilowatt hours
Smaller UK homes with relatively low hot water demands; for example flats, 2-bed terraced houses, 3-bed semi-detached houses
Up to 10 radiators
Small to Medium-sized homes
Large homes with high hot-water flow rates
3 or more bathrooms
36kw and above
Data source: Boiler central
Use the numbers from the table above to estimate your home’s boiler replacement cost. To do that, determine the appropriate boiler size range for your home. Then, decide what boiler brand and model to get. At this point, calculating the new boiler’s cost should be pretty straightforward.
Next, consult a few reputable local boiler installers and get free quotes and pick one provider. Finally, add the quoted labor costs to the boiler price; now you’re looking at numbers that are as close as it gets to reality.
Suppose two homeowners looking to heat up similarly sized houses decide to install the exact same combi boiler model. Would their project costs be the same? Not necessarily; actually, they could end up with different total installation costs.
Below are a few situations that could make the final number to be different from what it would have been otherwise:
- Homes with an external wall near the boiler typically have horizontal flues. What if you have no wall standing directly behind the boiler? In that case, the installation does become a little more complicated because you have to install a vertical flue. The adjustment would definitely increase the costs.
- If the flue’s location is near a door or window (or your neighbor’s), you must devise a way to safely direct flu waste away. In most cases, that’d mean spendintg extra money on installing a plume kit.
The flue in this situation exits through the nearest ceiling rather than a wall. While the additional cost borne might not be substantial, you’re spending more money nonetheless.
- Sometimes, it may be necessary to upgrade the main gas pipework to the current standard or even move it to a new location. The project might also require some additional brickwork. And all this could significantly alter the final cost.
To figure out if the new boiler installation would require pipework upgrades, look at the flue shape.
If the flue is square-shaped, there’s a decent chance you have an older home that doesn’t comply with the current gas safety regulations. Older homes tend to have 15mm pipes3 versus the current standard that requires 22mm piping.3
What if you have a round-shaped flue? The odds are you have a modern home that meets the current safety standard.
Analyze your energy bill and pay particular attention to the gas part of the math. Upgrading to an A-rated combi boiler with an efficiency rating of 92 percent could save you a nice sum on energy costs over time.
Your gas bill varies based on a number of factors. Some of the most critical ones is the size of your home, how well the house is insulated, and the boiler’s efficiency rating of the boiler.
Other factors that have a bearing on boiler running costs are your energy consumption behavior, your tariff, and any discounts received based on your bill payment method or being on a dual fuel tariff.
You’ve learned what the costs of new boiler installation look like for different home sizes. But knowing that isn’t useful unless you consult a good boiler company and installer for quotes. Use your analytical skills to parse the numbers and make the smartest financial decision possible.