Cut your energy costs with a new boiler

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What You Need to Know

  1. The cost of running a boiler accounts for around 60% of our energy bills, so an energy efficient boiler can make big inroads into one of our biggest household bills.
  2. Boiler efficiency is measured as a percentage these days, with it being illegal to install a new boiler with an efficiency of less than 88%. However plenty of old boilers have an efficiency of 70% or even less.
  3. The amount of money you can save by upgrading from the worst type of old boiler to a new energy efficient one is as much as £570 a year.
  4. The cost of a new installation can vary from £500 to £1,500 depending on the amount of work needed on your existing system, and whether you are moving the location of the boiler or not.
  5. A new boiler can vary in price from £500 to £2,500, but the difference tends to be in functionality rather than energy efficiency, with even the budget models having to comply with legal efficiency levels.
  6. As well as saving money, other considerations when changing your boiler include fuel type, space-saving if you are removing large old water cylinders and other equipment, and the amount of hot water you use. 

Why should I replace my Boiler?

One of the biggest expenses every household in the country has to contend with each year is their energy bills. There has been much criticism of the energy companies for the prices they charge, and whilst there are some new players on the market who have challenging the so-called ‘Big-Six’ monopoly, most of us are still stuck with big bills, no matter who our supplier is.

This means it is down to us to manage our energy usage to keep bills at a reasonable level, and when taking on that challenge the first place to look is your boiler.

Your boiler accounts for around 60% of you energy bills each years, and in the cold winter months this percentage is even higher. This means that having an energy efficient boiler can make a big difference to your energy bills.

Many of us tremble at the thought of replacing our boiler, fearing a huge up-front bill for the cost of the new machine, plus the complicated installation process. This can lead to many people with their years or even decades-old boiler, and unknowingly running up far bigger costs in their energy bills, than a new boiler would cost.

Boiler Efficiency

Boiler efficiency is measured by a classification system called the Sedbuk (Seasonal Efficiency of Domestic Boilers in the UK) system, which used to rate boilers on a scale from A-G, with ‘A’ being the most efficient, and ‘G’ the least efficient. Since 2009, this system has been brought into line with the standard European efficiency ratings, and is now displayed as a percentage.

All new boilers will display their efficiency using the new percentage scheme, but some older ones already installed in homes may still use the A-G measurements.

Since 2010, it has been illegal to install boilers into homes with an efficiency rating of less than 88%. In terms of your household bills, this is as efficient as it can get, and 98% efficient boilers would not give you any more noticeable savings than 88% efficient ones.

How much money can I save?

The key question for almost everyone reading this article is going to be how much money can I save, and the answer is, potentially, quite a lot.

It will depend on the age and efficiency of your existing boiler. If your house still has an old boiler with an efficiency rating of ‘G’ on the old system (below 70% in modern terms), a new boiler is likely to save you as much as £340 a year on your bills if you live in a semi-detached house and £570 a year if you live in a detached house. Even a mid-terraced house can expect savings of £280 a year.

Even if you have a significantly more efficient ‘D’ rated boiler (78% - 82%) you will see savings of around £175 a year in a semi-detached house, £300 in a detached house, and £145 in a mid-terraced house.

These figures are of course estimates, but have been compiled by the Energy Saving Trust, and so offer a reliable guide. It should also be noted that they do include any other energy saving measures you can take, such as fully insulating your home, so the potential savings as a whole you could make could be even higher.

How much does it cost to buy and install a new boiler?

The cost of buying and installing a new boiler will vary considerably depending on the type of boiler you have, the amount of work that needs doing to install it, and the new boiler you are buying.

  • Boiler Type: If you have an old fashioned gas, or even oil fired boiler, you are almost certain to have a separate hot water cylinder in the house to store hot water. This means that you have two choices, a new regular boiler with a new water cylinder, or a combi-boiler.

A combo-boiler doesn’t need a hot water cylinder, as it heats hot water on demand. They are less efficient than regular boilers, but hot water cylinders are even more inefficient at retaining heat, meaning that overall a combi-boiler is the most efficient option.

  • Location: Keeping your boiler in the same position will be much more cost effective than moving it elsewhere. Changing location will require complex plumbing work to move the pipes and can be expected to add around £500 to any installation bill.
  • Mechanical Flush: If your heating system is very old it might require a mechanical flush. This involves putting chemicals into the system to clean the pipes, which are flushed through with a pump, and is likely to cost around £500.
  • Converting your system: If you are upgrading from a very old-fashioned boiler, such as one which heated water using gas heat only, you can expect installation costs to be quite a bit higher as you are likely to need additional changes to your flue, add a condensation drain, and remove old equipment, as well as do the other work mentioned above. Costs could go as high as £1,500.

In total, you can expect to pay anything from £500 - £1,500 to install a new boiler. Always be sure to use a gas-safe approved installer. Anyone who offers to do the work for less, but doesn’t have the correct accreditation is not a qualified gas installer, and you could be putting your home and your family at risk.

The price of new boilers themselves have come down considerably in recent years, and a budget model can now be picked up for as little as £500.

More expensive model are of course available, and you can spend as much as £2,500 or even more if you so wish. These models tend to offer more functions, such as changing your settings via an app on your mobile phone, but in terms of energy efficiency, and therefore the amount of money you can expect to save on your bills, there is very little difference between them.

What other considerations are there?

There are of course a few other factors which you also have to take into consideration:

  • Fuel Type: Most people these days will opt for a gas boiler as they are generally more cost-effective than those powered by other fuels. However, many homes in rural areas are not hooked up to mains gas, and this can cause a problem.

If this is a problem you are facing, you can contact the company which operates the gas supply in your area to enquire about the costs of getting connected to the mains. In some cases, a connection may be available for free.

Otherwise your only option is fuel oil, which can be more expensive and involve installing a more expensive boiler as well.

  • Size: When choosing the type of new boiler you want to install, size can be a big consideration. Hot water cylinders and other old-fashioned equipment can take up a great deal of space, so if you live in a flat or a small house, or need the extra space, a combi-boiler can offer a great space-saving alternative.
  • Hot Water Usage: The amount of hot water you use can directly influence the choice you make on a new boiler, as there is a relationship between the costs of the two.

The general rule of thumb is if you have a large family and use a lot of water, a regular boiler is likely to be the most cost effective option for you. If however you have a smaller household, and use less water, a combi-boiler is probably the best option for you.


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