If your gas boiler is showing signs of trouble, you’re probably wondering about the cost of repairs before calling an engineer. At NJ Lees Plumbing & Heating, we understand that unexpected boiler repairs can be concerning, especially when you’re unsure about the price. This guide will help you understand the typical costs you might face in 2026 and what factors affect the final bill.
What Affects Gas Boiler Repair Costs?
The cost of repairing a gas boiler varies considerably depending on several factors. The type of fault is the primary consideration, minor issues like a worn-out pump or faulty thermostat typically cost between £150 and £400 to repair. More complex problems such as a heat exchanger fault or gas valve replacement can range from £400 to £800. If your boiler requires a complete replacement rather than repair, you’re looking at a significantly higher investment.
The age of your boiler also impacts repair costs. Older models may have less availability of spare parts, which can increase the price. Additionally, if your boiler is still under warranty and the repair is covered, you may qualify for free repairs or reduced costs. As Gas Safe registered engineers, our team at NJ Lees can assess your boiler and advise whether repair or replacement is the most cost-effective solution.
Common Boiler Problems and Typical Repair Costs
Understanding common issues can give you a better idea of what to expect. A broken thermostat usually costs £120 to £300 to replace, while a malfunctioning pump typically ranges from £200 to £400. Pilot light issues are often among the cheapest to fix at £80 to £200. However, a cracked heat exchanger is one of the most expensive repairs, potentially costing £600 to £1,200 or more, depending on your boiler model.
Other common repairs include fixing a leaking boiler, which might cost £150 to £500, and replacing a faulty pressure relief valve at around £200 to £400. At NJ Lees, our Gas Safe engineers will diagnose the exact issue and provide you with a clear quote before starting any work.
When Should You Repair vs. Replace?
If your boiler is less than 10 years old and the repair costs less than 50% of a replacement boiler’s price, repair is usually the better option. However, if your boiler is older than 15 years, has multiple faults, or repair costs exceed £500, replacement might be more economical in the long run. A new energy efficient boiler can reduce your heating bills by up to 30% compared to older models.
Our team can help you make this decision. Contact NJ Lees on 01903 530 851 for a professional assessment and advice tailored to your specific situation.