A £2,500 boiler on 10-year finance at 11.9% APR actually costs £4,340 by the time you’ve finished paying. The same boiler on 24-month 0% finance costs exactly £2,500. Which plan you should take depends on three factors that most installers don’t explain clearly on their website, because the longer, more expensive option is more profitable for them.
This guide breaks down how boiler finance actually works in the UK, what the major installers offer, the real total cost of each option, and when finance is the wrong answer entirely.
How boiler finance actually works
When you buy a new boiler through an installer that offers finance, you’re not borrowing from the installer. You’re borrowing from a consumer finance company, usually Novuna Personal Finance, V12 Retail Finance, or Omni Capital, that the installer partners with. The installer gets paid in full upfront by the lender. You then repay the lender over the agreed term.
Three consequences of this structure that matter to you:
- The lender decides whether you qualify, not the installer. Your application is a regulated credit check performed by the finance company.
- Your agreement is with the lender, not the installer. If you miss payments, the finance company pursues you. If the finance terms are misrepresented, the complaint goes to the Financial Ombudsman, not to the installer.
- APR offers vary by lender, not just by installer. Two installers using the same lender will often have very similar rates. Two installers using different lenders can differ by 2 to 3 percentage points on the same term.
The APR trap: why 10-year 0% doesn’t exist
Most installers advertise “0% APR finance” prominently on their boiler product pages. What rarely gets prominent billing is that 0% APR only applies to shorter terms, usually somewhere between 12 and 48 months. The longer interest-bearing options, typically 5 to 10 years, carry APRs between 9.9% and 12.9%.
Here’s what that difference costs you on a £2,500 boiler:
| Plan | APR | Term | Monthly | Total cost | Interest paid |
|---|---|---|---|---|---|
| 0% short-term | 0% | 24 months | £104.17 | £2,500 | £0 |
| 0% mid-term | 0% | 48 months | £52.08 | £2,500 | £0 |
| Standard interest | 11.9% | 60 months | £55.50 | £3,330 | £830 |
| Long-term interest | 11.9% | 120 months | £36.17 | £4,340 | £1,840 |
Illustrative monthly payments calculated on a £2,500 financed balance with no deposit. Actual rates vary by installer and credit profile.
The 120-month plan produces a small, comfortable monthly payment. It also costs you an extra £1,840 on top of the boiler’s price, paid out over the full length of the boiler’s expected lifespan.
Put differently: if you take the 10-year plan, you’ll still be paying for the boiler in year 10, by which point it’s out of warranty and possibly nearing replacement. The low monthly figure is engineered to feel affordable, and it is. It also carries the highest lifetime cost of any option on the table.
What each major UK installer offers
The headline APR is only part of the comparison. Minimum and maximum terms, deposit flexibility, and the specific lender used all affect which installer’s finance deal suits your situation.
| Installer | 0% APR terms | Interest-bearing terms | Deposit |
|---|---|---|---|
| BOXT | 3 to 5 years | Up to 10 years at 10.9% | £0 available |
| Heatable | 1 to 4 years | 3, 5 or 10 years at 11.9% | 25% recommended for best rates |
| British Gas | 4 years | Extended via Hitachi Capital | £0 available |
| E.On Next | 1 to 3 years | Up to 10 years at around 8% | Up to 50% deposit supported |
| Warmzilla | 1 to 2 years | 3 to 10 years at 10.9% | Flexible |
Rates and terms subject to change. Always confirm current offers directly with the provider before signing.
The meaningful differences in this table:
- E.On Next’s long-term APR of around 8% is noticeably better than the 10.9% to 11.9% offered elsewhere. On a £2,500 loan over 10 years, that’s roughly £500 saved in interest.
- BOXT offers 0% on terms up to 5 years, which is the longest 0% window of the major installers. If you want low payments without paying interest, this is the plan to look at.
- Heatable’s 25% deposit preference isn’t a hard requirement but you’ll notice the difference in APR tier if you can manage it.
Deposit strategy: when to put money down
A deposit does three things. Most obviously, it reduces the amount you borrow. Less obviously, it improves the APR tier the lender offers, because larger-deposit applicants are treated as lower-risk. Third, a deposit can unlock 0% APR plans you wouldn’t qualify for at zero down.
The short rule: if you can afford a 0% plan, take one. If the monthly payment on a 24-month 0% plan stretches you, a 25% deposit plus a 48-month 0% plan is the next-best answer. Long-term interest-bearing finance is a last resort, not a default.
Bad credit: what actually changes
You can still get boiler finance with poor credit. The terms are materially worse, and in many cases you’d be better off with an alternative form of borrowing.
With a credit score below 600, typical outcomes are:
- APRs of 15% to 25% rather than 10% to 12%
- Shorter maximum terms, usually capped at 5 years
- A deposit requirement of 20% or more
- Possibly a guarantor on the agreement
In this situation, the maths often flips. A personal loan from a credit union, which is rate-capped at 42.6% APR but typically offered at 15% to 25% to members, can work out cheaper than subprime boiler finance because the term flexibility is better. A 0% purchase credit card, if you can get approved, costs nothing during the promotional period. Both routes are worth checking before signing an installer’s high-APR finance agreement.
- ECO4 grant eligibility. If you claim qualifying benefits, a replacement boiler may be free.
- Your local authority’s boiler grant scheme. Several councils run top-up funds beyond ECO4.
- Personal loan quotes from your bank and one credit union for direct comparison.
- A 0% purchase credit card, if your limit and repayment capacity allow it.
Alternatives that are often cheaper
Boiler finance is one route out of several. For many people it’s not the cheapest, and it’s rarely the most flexible. Here’s how the common options stack up:
| Option | Typical rate | Suitable for |
|---|---|---|
| ECO4 grant | Free | Homeowners claiming qualifying benefits |
| Personal loan (prime) | 7% to 9% APR | Good credit, prefer a separate agreement from the installer |
| 0% purchase credit card | 0% for 12 to 24 months | Good credit, confident you can clear the balance in time |
| Credit union loan | 12% to 25% APR | Poor credit, existing union member |
| Boiler finance (0% APR) | 0% | Good credit, short term affordable, want convenience |
| Boiler finance (interest) | 10% to 12% APR | When no other option is available |
Notice where installer finance sits in this list: in the middle, not at the top. It’s often convenient, because the application happens inside the installer’s quote flow and approval is quick. But convenience isn’t the same as value, and the convenience premium is real money over a 5 or 10 year term.
When finance is the wrong answer
Four situations where taking boiler finance is usually a mistake:
You have savings that cover the cost
Paying upfront means no credit application, no interest, no 10-year commitment. If £2,500 is sitting in a current account earning nothing, using it is almost certainly better than paying an installer 11.9% APR. The exception is if you’d be draining an emergency fund entirely. Keep a float, but don’t finance a purchase you could cover.
You qualify for ECO4
A free boiler under the Energy Company Obligation scheme beats any finance deal on earth. Qualifying benefits include Pension Credit Guarantee Credit, Universal Credit, Income Support, income-related Employment and Support Allowance, and several disability-related benefits. If you’re eligible, apply for a grant before agreeing to any paid installation.
You can get a cheaper personal loan
If your bank offers a 7% APR unsecured loan of £2,500, that’s materially cheaper than 11.9% boiler finance. The application adds a day or two to your timeline, but saves hundreds in interest over a 5-year term.
Your boiler isn’t actually broken
Installers sometimes push replacement more aggressively than a neutral engineer would. If your existing boiler is 8 years old, serviceable, and working, paying for repair and continuing to save towards a future replacement can be the right call. Get a second opinion from an independent Gas Safe engineer before agreeing to replace a unit that might have another 2 or 3 years in it.
Frequently asked questions
Yes. BOXT, Heatable, and British Gas all offer £0-deposit finance plans. Your APR tier and maximum term may be less favourable than with a deposit, and you’ll need a reasonable credit score to be approved.
Yes. All FCA-regulated consumer finance requires a credit check. The finance company performs it, not the installer. A soft search happens when you view your options; a hard search takes place when you submit a full application.
Standard consumer credit consequences apply: a late fee, a mark on your credit file, and eventually a default if unpaid. The boiler is not repossessed, because it’s plumbed into your home, but the debt remains enforceable through standard means.
Generally yes, without penalty, on FCA-regulated agreements longer than 12 months. Always check your specific terms. Early settlement is particularly valuable on interest-bearing plans because you stop accruing interest from the settlement date.
It depends on the card. A 0% purchase credit card you can clear within the promotional period is usually cheaper than boiler finance of any kind. A standard credit card at 22% APR is usually worse than 10.9% installer finance.
The boiler stays with the property, but the finance agreement stays with you. Your repayments continue as normal from your new address. You can’t transfer the agreement to the buyer of your old home, so factor this into longer-term decisions if you’re likely to move in the next few years.