New Boiler Installation
Choosing a new boiler is less about picking a brand and more about correctly sizing it to the property — an oversized boiler cycles inefficiently and costs more than it should, while an undersized one struggles to keep up with demand, particularly for hot water in larger households. Genuinely new-build homes completed under the current Future Homes Standard have a different consideration again: from 2025, new-build properties are expected to use low-carbon heating (like a heat pump) rather than a traditional gas boiler as standard.
What's Included
- Boiler sized correctly for the property, not a default one-size choice
- Combi, system, and regular boiler options explained honestly for your situation
- Removal and safe disposal of the old boiler included
- Full commissioning and manufacturer warranty registration
How It Works
- 1 Survey the property — number of bathrooms, hot water demand, existing pipework and flue route
- 2 Recommend a boiler type and output size matched to that survey, with reasoning explained
- 3 Install, including any necessary pipework or flue changes
- 4 Commission the boiler, register the manufacturer warranty, and explain the new controls
Common Issues
- • An old boiler no longer worth repairing
- • Existing boiler undersized for current household hot water demand
- • New-build/extension projects needing to confirm current heating regulations
Pricing: Quoted individually after a survey, based on boiler type and output (indicative — confirm actual pricing with Rainbow Fix Ltd)
New Boiler Installation — Frequently Asked Questions
What's the difference between a combi, system, and regular boiler, and which do I need?
A combi boiler heats water on demand with no separate cylinder or tank, which suits smaller households with lower simultaneous hot water demand; a system boiler works with a separate hot water cylinder (good for larger households needing more hot water at once, especially from multiple bathrooms); a regular (conventional) boiler uses both a cylinder and a loft tank, and tends to suit larger or older properties, or a straight replacement where that pipework already exists. The right choice depends on your household size and existing pipework, which is exactly what the survey stage is for rather than defaulting to whichever is currently most popular.
How do I know what size (output) boiler I need?
Boiler output needs to match the property's heat demand and hot water usage pattern, not simply be sized up "to be safe" — an oversized boiler actually runs less efficiently because it short-cycles rather than running a longer, steadier cycle. This is calculated from the number of radiators, room sizes, insulation, and (for a combi) the number of bathrooms likely to want hot water at once, which is why a proper survey matters more than picking a size off a shelf.
I'm building a new-build extension or annexe — can I still fit a gas boiler?
This depends on whether the space counts as a genuinely new dwelling under current Building Regulations — from 2025, new-build homes are expected to use low-carbon heating (typically a heat pump) rather than a traditional gas boiler as the default, under the Future Homes Standard. An extension to an existing heated home is generally treated differently to a brand new, separate dwelling, so it's worth clarifying which situation applies to your project before assuming either option is automatically available.
Does a new boiler come with a warranty, and does it require anything from me to keep it valid?
Yes — new boilers come with a manufacturer warranty, typically ranging from around 2 years up to 10+ years depending on the model and manufacturer, but nearly all of them require proof of annual servicing by a qualified engineer to remain valid, which is worth factoring into your ongoing costs from the start rather than being caught out later. The installation includes registering the warranty in your name as part of the commissioning process.