Choosing the perfect boiler for your home is an important decision that affects your comfort, energy bills, and heating efficiency. With so many options available, it can feel overwhelming.
To choose the perfect boiler, consider your home’s size, hot water needs, and heating system. Combi boilers are great for small homes with low hot water usage, while system and heat-only boilers combined with a hot water cylinder suit larger homes with multiple bathrooms. For the best results, use an expert installer.
This guide will break down everything you need to know, helping you select the best boiler for your needs.
What to consider when choosing a boiler for your home
Several factors determine the best boiler for your needs, including fuel type, efficiency, budget, and installation requirements. Here, we explore the key elements to help you make an informed decision.
Boiler types
Before we get into the pros and cons of each type of boiler, let’s take a quick look at the three most common types of gas boiler – combi, heat only and system.
| Type | Also called | Brief description |
| Heat only | Conventional boiler, regular boiler | Require a cold water tank in the loft as well as a hot water cylinder, normally a low pressure system. |
| System boiler | Sealed system boiler | Work with an unvented hot water system, ideal for homes with multiple bathrooms. |
| Combi boiler | Combination boiler | Provides heating and instant hot water without a separate cylinder. |
See our detailed descriptions and the pros and cons of each type of boiler below.
Fuel type
Most boilers run on mains gas, typically the most cost-effective option. However, if your home is off the gas network, you might consider LPG, electric, or oil boilers.
Boiler size
What size boiler you need depends on your home’s heating and hot water demands.
You should consider:
- Property size – for medium homes (3–4 bedrooms), a 30–35kW boiler is usually sufficient.
- Number of radiators
- Number of bathrooms and hot taps used simultaneously
- Current heating system
- Hot water storage requirements
A qualified heating engineer can assess your home and recommend the best power output to meet your needs.
Energy efficiency
Modern boilers are designed to be highly energy efficient, reducing carbon emissions and lowering heating bills. Look for A-rated condensing boilers, which recover heat from exhaust gases to improve efficiency.
Budget and installation costs
While initial costs can vary, investing in a high-quality boiler with a long warranty can save you money in the long run. Consider the upfront cost and potential savings from reduced energy consumption and maintenance.
How to choose between boiler types
Different types of boilers suit different homes. Take a look at our comprehensive list of pros and cons to decide which might be best for your home.
Combi boiler
Advantages of a combi boiler
- Combis provide instant hot water, which heat-only and conventional boilers do not.
- Combi boilers are generally the most energy-efficient option for most UK homes.
- Their compact design saves space as there is no need for a separate cylinder to store hot water. So you can ditch the old cold water storage tank in the loft if you have one.
- They have lower maintenance costs as the integral heating and hot water functions are covered by the boiler manufacturer’s warranty.
Disadvantages of a combi boiler
- They don’t work well in properties where there is poor water pressure coming into the house and/or there are poor flow rates.
- Hot water flow rates are reduced if two or more taps/showers/baths are running simultaneously.
What type of properties benefit from combi boilers?
Combis are ideal for flats and small to medium-sized houses with one bathroom. They are also best for homes with good mains water pressure and low to moderate hot water demands.
Heat only boiler
Advantages of a heat only boiler
- They are the cheapest type of boiler, so replacement costs are low.
- They are ‘kinder’ to older central heating systems that may leak from the high-water pressure delivered by system or combi boilers.
- Heat-only boilers rely on a circulating pump to circulate water from the cold water storage tank, so if your area suffers from low mains water pressure, you will be unaffected.
Disadvantages of a heat only boiler
- Less energy-efficient than modern pressurised systems, leading to higher heating bills.
- Higher maintenance costs, as only the boiler is covered by the manufacturer’s warranty. If other system components, such as the hot water tank, valves, and pumps, break down, they could be costly to repair or replace.
- There are no heat only boilers manufactured with stainless steel heat exchangers; they are only made of aluminium, which is a poorer-quality material.
What type of properties benefit from heat only boilers?
Suitable for large or older homes with traditional heating systems, multiple bathrooms, low mains water pressure, and an existing hot water storage cylinder.
System boiler
Advantages of a system boiler
- When combined with an unvented hot water cylinder, system boilers deliver good hot water flow rates to multiple outlets simultaneously, so they are great for homes with a high demand for hot water.
- As more of the system’s components are integral to the boiler, the manufacturer’s warranty covers it all.
Disadvantages of a system boiler
- They require a hot water cylinder so they take up more space than a combi boiler.
What type of properties benefit from system boilers?
System boilers are generally best for larger homes with multiple bathrooms where simultaneous hot water usage is common. Suitable for properties with high hot water demands and no space for a cold water storage tank.
How to choose between boiler brands
It’s a no-brainer that you should install a good-quality boiler. This will not only ensure reliable, good performance but also minimise maintenance issues in the future.
Consider the materials of the key components. High-quality models feature brass hydro blocks and stainless steel heat exchangers for durability, whereas some are made of plastic.
Good-quality heat exchangers are made of stainless steel, while lower-quality heat exchangers are made of aluminium. Lower-cost materials are more likely to malfunction and cause leaks or other breakdown problems, which can prove inefficient and costly, so it is not recommended to buy cheap.
JPS Plumbing, Gas and Electrical’s recommendations
Valliant boilers
Vaillant boilers are a top-quality brand with stainless steel heat exchangers and brass hydro blocks. We recommend their ecoTEC Plus range, which includes combi and system boiler options.
There is no heat only boiler on the market that is made with stainless steel and brass components. They all have aluminium heat exchangers and plastic hydroblocks. We believe the best option for a heat only boiler is the Vaillant ecoFIT Pure range.
The standard warranty is 5 years, but, as a Vaillant Advance Mastertech Installer, JPS Plumbing, Gas and Electrical can offer a 10-year warranty on the Vaillant range.
Watch Jamie explain the benefits of a Valliant boiler on our Youtube channel.
Baxi boilers
The Baxi 800 range of combi boilers and system boilers has stainless steel and brass components. They are high quality and efficient. The Baxi 600 range is exactly the same as the Baxi 800 range; the only difference is the warranty period. Baxi’s heat only range is a completely different boiler and we actually don’t recommend these boilers, instead we suggest a Vaillant or a Glow-worm.
As a Baxi-approved installer, JPS Plumbing, Gas and Electrical can offer a 10-year warranty on the Baxi 800 range, and a 7-year warranty on the Baxi 600 range.
Watch Jamie explain the benefits of a Baxi boiler on our Youtube channel.
Main boilers
The Main Eco Compact Combi boiler has the stainless steel and brass components we’re looking for. This is our ‘go to’ recommendation for a budget range boiler and it is very popular with landlords.
As the hydroblocks and heat exchangers are made from the higher quality materials, they are still very good quality boilers. Incidentally, Main is part of the Baxi family and this boiler is basically the same boiler as the Baxi 800 and Baxi 600 range, it’s just got a different front cover.
As the Main boiler is Baxi’s budget option, there is a 5-year warranty period.
Watch Jamie explain the benefits of a Main boiler on our Youtube channel.
Glow-worm boilers
Glow-worm is Vaillant’s budget brand and is a popular choice with landlords. Reflecting their cheaper prices, in the Glow-worm Energy range, the heat exchangers are made of aluminium instead of stainless steel and the hydroblocks are made of plastic instead of brass.
The standard warranty is 7 years, but, as a Vaillant Advance Mastertech Installer, JPS Plumbing, Gas and Electrical can offer a 10-year warranty on the Glow-worm range.
Watch Jamie explain the benefits of a Glow-worm boiler on our Youtube channel.
Looking for a new boiler? Get in touch
JPS Plumbing, Gas and Electrical serves homes and businesses throughout the South Coast. Our friendly and experienced team of engineers is here to help with expert advice and professional installation. Whether you need a boiler replacement or a completely new system, contact us today for a free, no-obligation quote or get an instant boiler quote here.
Frequently asked questions – how to choose the perfect boiler for your home
Will getting a new boiler save me money on my energy bills?
Modern A-rated boilers are much more efficient than old non-condensing boilers. They will undoubtedly save energy, which in turn will save you money. According to the Energy Saving Trust, as of February 2025, upgrading from an E-rated to an A-rated boiler in an average semi can save at least £200 per year.
How often does it need servicing?
All boilers should be serviced every year. For modern boilers, the service is more of a safety check, to clean out the condensate trap and to make sure all the component parts are running correctly. For an older boiler, as well as the safety checks, of course, it’s more about cleaning the heat exchanger out and making sure that any soot and other particles aren’t in the boiler and getting in the way of the flame.
If I want a boiler installed, what is the process?
A boiler should be serviced annually to ensure safety and efficiency. Regular servicing helps prevent breakdowns and prolongs its lifespan. Book your annual boiler service online today with JPS Plumbing, Gas and Electrical. For ultimate peace of mind, consider our boiler cover, which also includes essential boiler repairs.
What is the difference between a combi boiler and a system boiler?
A combi boiler provides instant hot water without a storage tank, making it ideal for small homes. A system boiler works with a separate hot water cylinder, suitable for larger homes with higher hot water demands.