There are three main types of gas boiler. The right one depends on how many bathrooms you have, your water pressure and how your heating is set up now.
Heats your radiators and gives you hot water straight from the mains whenever you turn on a tap. No hot water cylinder or loft tanks, so you get space back.
Best for: Flats and homes with one bathroom.
Heats your radiators and a hot water cylinder, usually kept in an airing cupboard. There are no loft tanks, and stored hot water means several taps can run at once.
Best for: Homes with two or more bathrooms.
Also called regular or conventional boilers. They work with a hot water cylinder and tanks in the loft, so they suit traditional heating systems.
Best for: Older homes, low mains water pressure, or keeping your existing setup.
Most manufacturers make a good, better and best range. Here’s how each brand’s line-up compares, from entry level to premium. Pick a brand to jump straight to it.
Worcester Bosch boilers are built in Worcester and are some of the most popular in the UK. The Greenstar range runs from the great-value 2000 up to the premium 8000.
Worcester’s great-value combi. It’s compact enough to fit between kitchen wall cupboards and one of their quietest combis, ideal for flats and homes with one bathroom.
Combi
The all-rounder of the Greenstar range, with quiet running and a full colour display. A great fit for most family homes.
CombiSystem
Worcester’s premium range, with the most powerful wall-hung combis they make. Built for bigger homes with more than one bathroom.
CombiSystemHeat only
Vaillant boilers are hand-built in Derbyshire and are known for quiet, reliable running. The range goes from the great-value ecoFIT pure to the popular ecoTEC plus.
Vaillant’s great-value range. It’s compact enough for a kitchen cupboard, with top or rear flue options for a neat fit.
CombiSystemHeat only
A no-fuss combi with Vaillant’s aquaCOMFORT feature for faster hot water, built to the same quality as the ecoTEC plus.
Combi
Vaillant’s core range, with the widest choice of types and sizes and a clear full text display. Suits most homes.
CombiSystemHeat only
Ideal have been making boilers in Britain since 1906. Their range covers everything from compact combis like the Instinct and i-mini to the premium Vogue Max.
Ideal’s compact, great-value combis, small and light enough to tuck into a kitchen cupboard. A good fit for flats and smaller homes.
Combi
Adds a large colour screen and comes with an Ideal system filter in the box.
CombiSystemHeat only
Ideal’s flagship, built with a stainless steel heat exchanger and premium components.
CombiSystem
Viessmann’s Vitodens boilers bring German engineering and a stainless steel heat exchanger to every model, from the great-value 050-W to the flagship 200-W.
Compact, light and quiet, the 050-W gives you Viessmann quality at a great price.
CombiSystem
The sweet spot of the range, with strong hot water flow rates and a heat only version for older systems.
CombiSystemHeat only
Viessmann’s flagship wall-hung boiler, a powerful and flexible choice for larger homes.
CombiSystem
Baxi have been around since 1866, making them one of Britain’s longest-running heating brands. Their numbered range makes choosing easy: the higher the number, the higher the spec.
A simple, reliable boiler at a lower price, ideal for smaller homes.
CombiHeat only
A step up in features and guarantee length, with a version for every type of system.
CombiSystemHeat only
Baxi’s top range, with brass and stainless steel components and a magnetic system filter in the box.
CombiSystemHeat only
ATAG boilers are designed and built in the Netherlands, with a stainless steel heat exchanger in every model. The range covers combi, system and heat only boilers, with the iC Economiser at the top.
ATAG’s popular combi, with a stainless steel heat exchanger and a compact case that fits neatly into a kitchen cupboard.
Combi
The system boiler version of the iC, made to work with a hot water cylinder in homes with more than one bathroom.
System
ATAG’s top combi. It uses heat from the flue to warm the incoming cold water, so it needs less gas to make hot water.
Combi
We fit boilers in homes of every size, and in shops, offices, schools and other commercial buildings across Sheffield and South Yorkshire.
New boilers for houses, flats and bungalows, from a straight swap to a full system upgrade.
Higher-output boilers for shops, offices, schools, churches, care homes and landlords with larger buildings.
Already know the brand you like? Our comparison guides explain what you get as you move up each range, so you only pay for what your home needs.
For most flats and homes with one bathroom, a combi is the simplest choice. If you have two or more bathrooms, a system boiler with a hot water cylinder usually works better. A heat only boiler makes sense if you want to keep a traditional setup or your mains water pressure is low. We confirm the right option when we survey your home.
All six brands on this page are well established, with good parts availability and solid guarantees. The best choice depends on your budget, the space you have and how much hot water your home uses. Compare the ranges above, or ask us for a recommendation.
Often, yes. It means removing the hot water cylinder and loft tanks, which frees up space. We check your mains water pressure and flow first to make sure a combi will give you a good shower.
A combi heats water on demand straight from the mains, so there's no cylinder. A system boiler heats a cylinder of stored hot water, which means several taps and showers can run at the same time.
It depends on how many bathrooms and radiators you have and how much hot water you use. A boiler that's too big wastes money and one that's too small struggles, so we size it properly at your survey.
Most like-for-like boiler swaps are done in a day. Moving the boiler or changing the type of system, such as heat only to combi, usually takes two to three days.
Tell us a little about your home and we’ll recommend the right type, size and model, then give you a clear quote.
