The short answer
Paying monthly for a new boiler means taking out credit, usually arranged by the installer through a lender. It can spread a cost of a few thousand pounds over several years, but it almost always costs more in total than paying upfront, unless the deal is genuinely 0% with no fees and no price uplift. To compare offers fairly, look at three numbers: the cash price, the APR, and the total amount payable. Check that the lender and any broker are authorised by the Financial Conduct Authority (FCA). This page is general information, not financial advice. If you are unsure whether borrowing is right for you, speak to an independent adviser or the free, government-backed MoneyHelper service.
What you are borrowing against
For scale, a like-for-like combi swap typically costs £2,200 to £3,400 fitted, a system boiler replacement £2,800 to £4,000, and a conversion from a system or regular boiler to a combi £3,000 to £4,200 (national ranges including VAT, checked October 2026). Get the fixed cash price in writing first. Every finance offer should be measured against it.
The numbers that matter
| Term | What it means | Why it matters |
|---|---|---|
| Cash price | What you would pay upfront | Your baseline for every comparison |
| Deposit | Any amount paid at the start | Reduces what you borrow |
| APR | Annual percentage rate, the yearly cost of the credit including interest and required fees | The fairest way to compare credit offers of a similar length |
| Representative APR | The rate at least half of approved customers get | You may be offered a higher rate after a credit check |
| Term | How many months you pay for | Longer terms mean lower monthly payments but usually more interest in total |
| Total amount payable | Everything you pay over the term, deposit included | The real cost of the boiler on finance |
The monthly payment is the number sales material leads with, and it is the least useful for comparison. A lower monthly figure over a longer term can cost you far more overall.
How to compare two offers
- Ask each installer for the cash price and the finance price for the same boiler and the same work.
- Check the term, APR and total amount payable on each.
- Subtract the cash price from the total amount payable. That difference is the cost of borrowing.
- Compare that cost against other ways of paying, such as savings or credit you arrange yourself.
- Check what happens if you want to pay off early, and whether there is a charge.
If the finance price for a boiler is higher than the cash price for the same boiler, the 0% offer is not free. The cost has moved into the price.
Check the lender is FCA authorised
Anyone who lends money to consumers, or arranges credit as a broker, must be authorised by the FCA. Many installers act as credit brokers and introduce you to a lender. Before you sign:
- look up the lender’s name and firm reference number on the FCA register
- if the installer is arranging the finance, check they are listed as authorised to broker credit
- read the pre-contract credit information, which sets out the APR, term and total amount payable
- ask whether the installer receives a commission from the lender
If a firm is not on the register, or the details do not match, walk away.
Your protections
For most regulated consumer credit agreements:
- You have 14 days to withdraw from the credit agreement after signing. You would then need to repay the amount borrowed, usually with any interest for the days you had it.
- You may have a claim against the lender as well as the installer if something goes wrong with the job, where the credit was arranged through the installer for that purchase. Ask the lender how this applies to your agreement.
- You can complain to the lender first, then to the Financial Ombudsman Service if you are not satisfied.
These rules can change and depend on the exact agreement, so check the current position on gov.uk or with the lender.
Questions to ask before signing
- What is the cash price, and is it the same if I pay monthly?
- What APR am I being offered after the credit check, not just the representative rate?
- What is the total amount payable?
- Is there a fee for paying off early?
- Who is the lender, and are you acting as a credit broker?
Paying monthly and making the right choice
Finance should never push you into a bigger or dearer boiler than the house needs. Settle the type and size first, using combi vs system vs conventional boilers and what size boiler do I need?. Then compare fixed cash prices using our boiler replacement cost guide, and only then look at how to pay.
City Boiler does not lend money or arrange credit. We connect you with independent Gas Safe registered installers, some of whom offer finance through their own lenders. Their terms are theirs, so check each one using the steps above. Find out more on the boiler replacement hub.
Common questions
Can I pay for a new boiler monthly?
Many installers offer monthly payments through a lender or credit broker, subject to a credit check. You can also use your own savings, a credit card or a personal loan arranged yourself. Compare the total cost of each route, not just the monthly figure.
Is 0% boiler finance really free?
It can be, if the cash price is the same as for someone paying upfront and there are no fees. Check whether the boiler costs more on the finance deal than it would for a cash buyer, and what happens if you miss a payment or the offer period ends.
How do I check a finance company is legitimate?
Look up the lender, and the installer if they act as a credit broker, on the Financial Conduct Authority register. Anyone offering or arranging consumer credit in the UK must be authorised. If they are not on the register, do not sign.
Can I cancel boiler finance after signing?
For most regulated consumer credit agreements you have a 14 day right to withdraw from the credit, though you would still need to pay for the boiler. Cancelling the installation contract itself is a separate matter. Read the agreement and ask before signing.