Boiler FAQs
Common questions about boilers — from choosing a new one to understanding how they work.
What are the different types of boiler?
There are three main types: combi boilers, system boilers, and heat-only (regular) boilers. Combi boilers provide heating and instant hot water without a storage cylinder, making them ideal for smaller homes. System boilers work with a hot water cylinder and suit homes with higher hot water demand. Heat-only boilers are designed for older properties with a traditional gravity-fed system and a feed-and-expansion tank in the loft.
How long should a boiler last?
A well-maintained modern condensing boiler typically lasts 10–15 years. Some high-quality boilers from brands like Worcester Bosch or Vaillant can last 20 years with regular annual servicing. Signs that a boiler is reaching the end of its life include frequent breakdowns, rising energy bills, difficulty sourcing spare parts, and visible corrosion.
How often should I service my boiler?
You should have your boiler serviced every 12 months by a Gas Safe registered engineer. Annual servicing keeps the boiler running safely and efficiently, maintains your manufacturer's warranty, and catches small problems before they become costly repairs.
Which boiler brands do you recommend?
We most commonly install Worcester Bosch and Vaillant boilers — both offer outstanding reliability, excellent parts availability, and strong warranty support. Viessmann, Ideal, and Baxi are also solid choices. We'll always recommend the best brand and model for your home's specific needs during our free survey.
What does an efficiency rating mean?
Modern boilers are rated on the ErP (Energy-related Products) scale from A to G. All new condensing boilers sold in the UK must achieve an A rating, meaning they convert at least 92% of fuel into useful heat. An efficient boiler can significantly reduce your gas bills compared to an older G-rated boiler, which may only be 60–70% efficient.
What warranty does a new boiler come with?
Warranties vary by brand and model, typically ranging from 2 to 12 years. Worcester Bosch and Vaillant offer up to 10-year warranties when installed by their accredited engineers. Halo Heating engineers are accredited with both manufacturers, so you'll receive the maximum warranty available. Always register your boiler warranty within the manufacturer's specified timeframe.
How much does a new boiler cost?
A new combi boiler installed typically costs between £1,800 and £3,500 depending on the model, complexity of installation, and any additional work required such as flue extensions or moving the boiler location. System boiler installations with a new cylinder can range from £2,500 to £5,000. We provide free, no-obligation quotes with transparent pricing.
Should I repair or replace my boiler?
A useful rule of thumb is the 50% rule: if the repair cost exceeds 50% of the cost of a new boiler, replacement is usually the wiser investment. Also consider the age of your boiler — if it's over 10 years old and breaking down regularly, a new energy-efficient boiler will likely pay for itself through lower energy bills. We'll always give you an honest assessment.
Why is my boiler making strange noises?
Boilers can make various noises, each indicating different issues. Banging or clunking often points to limescale build-up on the heat exchanger (kettling). Gurgling usually means trapped air in the system or low water pressure. Whistling can indicate a faulty pump or air in the pipes. Rumbling at startup may suggest sludge in the system. All of these warrant investigation by a qualified engineer.
What do boiler error codes mean?
Error codes are displayed on your boiler's control panel and indicate a specific fault. Common codes include low pressure errors, ignition failures, and sensor faults. You can often find a list of error codes in your boiler's manual. Some simple faults — like low pressure — can be resolved by homeowners, but for most fault codes it's safest to call a Gas Safe engineer. Call us on 01483 676108 for fast diagnosis.
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