At some point, every boiler has to be replaced. The question is when — and whether repair still makes sense at that point. Getting this wrong is expensive either way: paying for a major repair on a boiler that fails again six months later, or replacing a boiler prematurely that had plenty of life left.
Here is how our Gas Safe registered engineers assess whether a Devon boiler is worth repairing.
Age Is the Starting Point
Most modern condensing boilers have a working life of 10-15 years with annual servicing. Beyond 15 years, the probability of major component failure rises significantly. If your boiler is 12 years old or more, the repair-versus-replace calculation starts to shift.
That said, age is not the only factor. A 15-year-old boiler that has been annually serviced and has never had a significant repair can still have years of life left. A 10-year-old boiler that has been neglected may be near the end.
The Repair-to-Value Calculation
A rough guideline used across the industry: if the repair cost is more than half the cost of a new boiler installation, replacement is usually more cost-effective. This is particularly relevant when:
- The heat exchanger needs replacing (often the most expensive single repair)
- The boiler needs a gas valve replacement
- Multiple components are failing at the same time
For a new condensing combi boiler installed in a Tavistock or Okehampton property, installed cost is typically £1,500-£2,500 depending on the model and complexity. If a repair quote is above £800-£1,000, the calculation shifts firmly towards replacement.
Warning Signs That Suggest Replacement
Frequent breakdowns. If you have had two or more significant repairs in the last two years, the boiler is telling you something. Parts failures rarely come in isolation — when one component wears out, others are usually close behind.
Yellow or orange flame. A healthy gas boiler burns blue. A yellow or orange flame indicates incomplete combustion and the possible production of carbon monoxide. This is a safety issue requiring immediate attention. An engineer may be able to adjust the combustion, but in an older boiler this is often a sign of serious heat exchanger deterioration.
Carbon monoxide alarm triggering. If your CO alarm has triggered, get out of the property and call the Gas Safe emergency line. Do not assume a reset solves the problem. A boiler producing CO needs thorough investigation — and in many cases, replacement.
Constantly losing pressure. A boiler that needs topping up every few weeks has a leak somewhere. Sometimes this is a simple valve repair. In older boilers, it often indicates a failing pressure vessel or heat exchanger seam — neither of which is cheap to fix.
Significant rise in energy bills. Boiler efficiency drops as components age. A condensing boiler that was 90% efficient when new may be running at 75-80% after ten years of use. If your bills have risen without a change in usage, the boiler is a likely cause.
Reading Your Boiler's Fault Codes
Modern boilers display fault codes when they lock out. These are not always obvious, but they are useful information for the attending engineer. Common codes that suggest wear rather than a simple fix:
- H1 / F1 / EA fault codes (varies by brand): typically related to heat exchanger overheat — can indicate scale build-up, poor flow rate, or a failing component
- Ignition lockout codes (e.g. Vaillant F.75, Worcester E9): repeated ignition failures suggest either a worn igniter or pump issues
- Low pressure codes: if the boiler requires regular filling to maintain pressure, the cause needs investigating, not just topping up
When you call for a boiler repair, noting the fault code before the engineer arrives helps them arrive with the right parts.
New Boiler Cost Guide for Devon Properties
Installed costs for a replacement boiler in the Devon area (2026):
| Boiler type | Installed cost (approx) | Notes |
|---|---|---|
| Gas combi (mid-range) | £1,760–£2,400 | Most common in Tavistock and Okehampton terraces |
| Gas combi (premium) | £2,400–£3,200 | Longer warranty, better efficiency |
| Oil condensing combi | £2,800–£3,955 | Rural Devon properties without mains gas |
| Oil regular boiler + cylinder | £3,200–£4,500 | Larger rural properties, multiple bathrooms |
These figures include supply, installation, flue adaptation, and commissioning. They do not include power flush (£300–£500 if the system requires it before a new boiler is installed) or significant pipework alterations.
The Devon Rural Property Consideration
For properties with oil boilers — common across rural Devon, Dartmoor, and the Tamar Valley — the calculations are slightly different. Oil boilers tend to have longer working lives than gas boilers, partly because the servicing regime is more rigorous (OFTEC registration is required for all oil work). An oil boiler in good condition can run for 20+ years.
Modern oil condensing boilers are significantly more efficient than older pressure jet or Wallflame models. If you have a pre-2000 oil boiler, the efficiency uplift from replacement (from around 65-75% to 90%+) can justify replacement on running cost savings alone, even if the boiler is still functioning.
Landlord Requirements in Devon
Landlords in Devon have a legal obligation to have gas appliances — including boilers — serviced annually by a Gas Safe registered engineer, and to provide tenants with a copy of the Gas Safety Record (CP12 certificate) within 28 days of the check. Failure to do so is a criminal offence.
For a boiler that is failing regularly or approaching end of life, replacement before a tenancy begins is almost always the right commercial decision. Tenant callouts for boiler failures in winter are disruptive, expensive at emergency rates, and in the worst case can lead to local authority intervention if the property becomes uninhabitable.
We carry out annual boiler services and issue Gas Safe certificates on the day across the Tavistock service area.
What We Recommend
When we attend a boiler fault in Tavistock, Okehampton, Launceston, or surrounding rural Devon, we will always give you an honest assessment. If we believe replacement is more cost-effective than repair, we will say so — and if boiler repair is the right call, we will say that too.
We do not earn more from recommending replacement over repair. Our interest is in giving you accurate advice so the problem is properly resolved.
Request a quote online for boiler repair or boiler replacement across the Tavistock service area.