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Speedy Gas LondonTips for Buying the Best Replacement Boiler

Tips for Buying the Best Replacement Boiler


With so many different types of boilers available, how do you know which the best one is? If you’re ever in doubt, you can start from some good boiler manufacturer and brand reviews, including British Gas, Baxi, Vaillant and Worcester Bosch, according to how customers have rated them in the past. If you prefer to be guided by an expert, you can get in touch with us so that we can quickly help you. This guide contains useful information to get you started.

Video: Guide to Buying Your Boiler

For most, replacement boilers are the most expensive purchases in the household so finding the best option for your home is essential. Please take a look at Which video for a guide to finding and buying the perfect replacement boiler for your needs.

What to keep in mind when choosing a new boiler

Before having the boiler installed, you need to choose between them. You need to consider the following factors to find the best one for your needs.

  •  The Fuel Type: Most heating systems in UK homes is run on gas, which means a gas boiler is a necessity. However, there are other options for those not connected to the gas network (about 4.3m homes). Oil boilers and liquid petroleum gas (LPG) boilers are options. You could also opt for a back boiler to be connected to a wood burning stove. Check out our heating oil guide and guide to home heating systems to help find the right type for your needs.
  • The Boiler Type: There are different types of boilers, including the combination/combi boiler or a heat only boiler. The first will provide hot water and heat the radiators while the heat only boiler will provide hot water only. For more information, contact us for an opinion.
  • The Efficiency of the Boiler: About 60% of CO2 emissions from a home occurs in homes with gas central heating, Energy Saving Trust states. It makes it important to think about the efficiency so you can cut your carbon footprint as well a keeping your energy bills low.
  • The Heating Controls: There are times that you want to control your temperature and where or when it is operating. This also helps to lower your bills since you can only heat the rooms that need it. Replacing your boiler is a great time to consider heating controls too.

Installing a Boiler

70784938_1-Pictures-of-OIL-BOILER-BURNER-INSTALLATIONS-SERVICINGYou should never attempt the replacement installation by yourself. It has to be completed by the professionals. Check the Gas Safe Register to find someone who is competent. Corgi used to run this scheme. When talking to a tradesperson, as to see the ID card from the Gas Safe Register so you can run a quick website check for them. Speedy Gas professionals are all registered.

It is worth taking the time to shop around. Ask various installers for quotes. Here at Speedy Gas we’re confident you get a great, cost-effective service with us. Three quotes are the minimum that you should get and you want to check what these quotes include – find those that include call-out fees and any other costs that may occur. The headline discount may look great but you may be shocked when you see the labour and boiler charges. Do not forget a mediocre professional can end up making you waste much more money than expected!

We offer a service where the replacement boiler can be suggested and chosen for you. If you have already done your research, we will make sure you get the one that you want.

Prices of Boilers

The cost of the boilers depends on the brand, type and size that you need.

It is possible to buy one for less than £600 but you can find others that are more than £2,000. The problem is that higher price tag never guarantees that you will get the best boiler.

For an idea on the price, we put various boilers into categories in this table below:

Snapshot of typical boiler prices
Price band

Gas combi boilers

Gas heat-only boilers

Oil combi boilers

£400 – £700

7 boilers

 20 boilers


£700 – 900

10 boilers

14 boilers


£900 – £1,200

10 boilers

1 boiler



2 boilers

3 boilers

30 boilers


Please note that this is just a snapshot. Before deciding on a boiler, contact the manufacturer for the latest prices and if there are any offers available. You can also check boiler reviews to learn more about specific models and makes. You can get an overview of the biggest brands, rated by customers.

The Cost of Installing Boilers

vaillant boilersThe price doesn’t stop with the boiler.

Be careful when evaluating costs. Speedy Gas is always 100% transparent about service charges. With some companies, though, you need to factor in the installation costs, along with call-out charges, extra parts needed and other work to make sure your central heating system is up and running. You then need to remember about the VAT. You may find that the cost of the boiler is just a small fraction of the total cost for your replacement boiler.

To understand more about the pricing system for replacement parts, get in touch with us.

Combi Gas Boilers

Combination boilers are commonly referred to as combi boilers and are the most popular throughout the UK. They heat the water on demand and warm up the radiators.

There are different types of these boilers available. Most of them will heat your cold water straight from the mains whenever you need it, so there is no need for a storage tank or hot water cylinder.

The Benefits of Combi Gas Boilers:

  • All the components of the boiler are contained within the combi gas boiler system. It is compact and looks better than other types of boilers.
  • It eliminates the need for an expansion or feed tank for cold water, usually stored in the loft, so you can get the hot water as soon as you need it.

The Downsides of Combi Gas Boilers:

  • The boiler has moving parts, meaning that there is more chance of something going wrong.
  • Those with larger households may not benefit. The system is designed for households that don’t use hot water at the same time. You can’t run the bath and use the kitchen sink at the same time.

Heat Only Boilers

Heat only systems are open-vented and have a water tank. There are other components, including a circulation pump outside of the boiler. There will also be cold water needed, such as an expansion or feed tank in the loft.

The system is also known as the conventional boilers with the hot water stored in a storage tank or cylinder. When you know you need the hot water, there is an on/off switch so you only heat the water when necessary.

The Benefits of Heat Only Boilers:

  • When people need to use different hot water sources at the same time, they can, which is great for larger families.

The Downsides of Heat Only Boilers:

  • The hot water is stored in a tank and once that is used, you will need to wait for the boiler to heat the water again. When running a bath, you may not have hot water for a few hours afterwards.

Sealed Heat Only Systems

It is possible to buy a sealed heat only system, which is the heat only boiler without the external components. While there is the hot water cylinder, there is an expansion vessel within the boiler instead of an external expansion tank. This usually includes the circulation pump along with some valves.

Condensing Boilers

When you want your fuel to go further, condensing boilers are worth considering. Energy Saving Trust states that £310 a year could be saved by replacing your G-rated boiler with a condensing boiler that is highly efficient, especially one that improves your heat controls.

Before choosing, though, find out more about how condensing boilers work and how they differ from other options to heat your home.

How Do Condensing Boilers Work?

When you want an efficient, greener boiler, it is worth choosing a high-efficiency condensing system. They use the heat better, whether fuelled by oil or gas.

When you have a heat only system, some of the heat ends up wasted through the release of hot gases through the flue. In a condensing boiler, the heat is captured so the water that returns from the central heating system is heated. It makes it more efficient by needed less heat for all your needs.

Getting in touch with us, you will also find out the answers to all the questions commonly asked, including what should you do if the condensate pipe in the boiler freezes.

Non-Condensing vs. Condensing Boilers

You can get non-condensing and condensing heat only or combi boilers. Under new building regulations, all new boilers that are installed within a domestic property should be condensing boilers but there are some exceptions in rare cases.

Condensing boilers are fully sealed and the air comes from the outside, whereas its counterpart will take it from inside a room.

When it comes to safety, condensing boilers are better. There is not as much risk of the boiler sucking anything into the system, while being 25% more efficient, on average at least, than the non-condensing versions.

Oil Boilers

Around four million homes aren’t connected to the gas network in the UK, meaning that an oil-powered system is needed. This requires an oil boiler to be able to heat the home.

While this limits the choices, there is still a wide variety to choose between when looking for a replacement oil boiler to upgrade your system. Speedy Gas has tested over 20 models and can help you find the best one for your home. You can also use online comparison tools to get more information before we discuss your installation.

An Explanation of Oil Boilers

Heating through oil costs around £1,355 for a three-bedroom house, while gas systems cost between £770 and £950 per year depending on the boiler efficiency. LPG boilers cost around £1,300 per year. The system works very similar to the traditional gas system. The oil is used to heat the water, which will then provide hot water for the taps and to heat the radiators around the home.

There are combinations and heat only condensing boilers available. Most of the combination systems will have a hot water store within the boiler instead of offering instantaneous heating which most gas boilers will provide.

It is also common for the temperature of the hot water to decline as you use more water in the home. You can check out Which guide to home heating systems to find out more about the advantages and disadvantages to opting for oil central heating.

Efficiency and Maintenance of Oil Boilers

In general, oil is much more efficient than its gas counterpart so you get better value for your energy unit. However, the price of oil is still rising. You will need to find a supplier within your area, and Speedy Gas can help you in the London area.

According to changes to the building regulations, as of April1, 2007, all oil boilers need to have an 86% Sedbuk efficiency, at least, unless there is an exception made. Only condensing boilers have proven to meet this standard. Typical new boilers have 92%-93% efficiency ratings, compared to the 85% of the newer non-condensing systems and between 60% and 70% for the older ones.

When installing an oil boiler, you need to find a professional who is registered with the Oil Firing Technical Association (Oftec). You should have your boiler serviced every year to make sure it meets all safety requirements.


Where we go

Speedy Gas covers all of North London, NW, East London & Central London and surrounding districts. We can provide references from clients across London who we have provided boiler installations and heating / plumbing services to in the last year.

Get in Touch Today!

Mob: 078 1728 8668
Email: info@speedygaslondon.co.uk