How Much Could You Save With a New Boiler?


Most people think that buying a new boiler is eye-wateringly expensive. But with energy costs predicted to increase next year, the cost of heating your home with an inefficient system looks set to get bigger and bigger.

Throw in the risk of an unexpected breakdown and suddenly a new boiler might not seem that expensive, especially when you consider the range of financing options available on new boilers.

This blog post contains helpful tips to help you work out whether it’s worth investing in a new system.

• You could save more than £226 per year on heating bills depending on the age of your boiler and the size of your home.
• If your older boiler breaks down unexpectedly, it could cost you up to £400 to get fixed
• A new boiler could be cheaper than you expect, especially if you make use of one of our financing deals

Boiler efficiency savings

Gas and electricity together eat up about 4% the average household budget. For some poorer families, this figure is closer to 10%.

When the cost of heating your home makes up around 60% of your total annual energy bills, boiler efficiency savings can dramatically reduce your total expenditure.

Boiler efficiency measures how much energy your boiler uses to heat your home. If everything else stays the same, then the more efficient your boiler, the lower your bills.

Most modern boilers are super efficient, wasting only small amounts of energy. Older boilers are generally much less efficient. Some of the oldest boilers can waste as much as 30 or 40% of the fuel they use.

Boiler efficiency can be measured in a few different ways. These days, the most common is the Energy-related Products (ErP) system, which is mandated by the EU. Like other appliances including fridges and washing machines, every new boiler comes with an ErP label, scoring the machine from A+++ down to G.

A-rated boilers have an efficiency over 90%, while G-rated boilers are less than 70% efficient.

Some of the most efficient modern boilers, such as the Which? Best Buy Worcester Bosch Greenstar gas boilers can achieve efficiencies as high as 95%.

How efficient is my boiler?

If your boiler doesn’t have an efficiency rating, you can roughly work out its efficiency according to its age. Here’s a rough guide to boiler age and efficiency:

• Over 25 years old: 60-70% efficient
• 15-25 years old: 70-80% efficient
• 10-15 years old: 80-85% efficient

Remember that boilers can run less efficiently if they are not serviced regularly. We recommend servicing your boiler every year.

How much could I save with a more efficient boiler?

How much you could save with an efficient boiler will depend on a number of factors, including the efficiency of your current system, the size of your home and whether your home is detached, semi-detached or terraced.

To help keep things simple, we’re going to compare boiler efficiencies across Ofgem’s Typical Domestic Consumption Values (TDCVs). These values, which suppliers use to set prices, represent industry standard values for gas and electricity consumption in typical domestic homes.

There are three TDCV values for domestic gas consumption – low, medium and high. The low value is typical for flats, bungalows and small homes. Medium is for average-sized family homes, while the large value is for bigger houses.

In 2020, the TDCV values for gas consumption by category are:

  • Low – 8000 kWh
  • Medium – 12,000 kWh
  • High – 17,000 kWh

If the average unit price for domestic gas is 3.8 pence per kWh and we assume that Ofgem’s TDCVs are based on boilers that are 100% efficient, we can work out how much you could save by switching from a less efficient boiler to a more efficient boiler.

Boiler efficiency and annual cost in the ‘low’ TDCV category, including flats, bungalows and small homes

  • 100% efficiency:  8000 kWh  annual consumption,  £304.00 annual cost
  • 95%   efficiency:  8,400 kWh  annual consumption,  £319.20 annual cost
  • 90%   efficiency:  8,800 kWh  annual consumption, £334.40 annual cost
  • 80%   efficiency:  9,600 kWh  annual consumption, £364.80 annual cost
  • 70%   efficiency: 10,400 kWh annual consumption, £395.20 annual cost
  • 60%  efficiency:  11,200 kWh annual consumption, £425.60 annual cost

If you live in a flat, bungalow or small home, you could save more than £105 by switching from a very old (60% efficiency) boiler to a modern high efficiency (95%) unit.

Boiler efficiency and annual cost in the ‘medium’ TDCV category, including medium-sized family homes

  • 100% efficiency:  12,000 kWh  annual consumption,  £456.00 annual cost
  • 95%   efficiency:  12,600 kWh  annual consumption,  £478.80 annual cost
  • 90%   efficiency:  13,200 kWh  annual consumption,  £501.60 annual cost
  • 80%   efficiency:  14,400 kWh  annual consumption,  £547.20 annual cost
  • 70%   efficiency:  15,600 kWh annual consumption,   £592.80 annual cost
  • 60%  efficiency:   16,800 kWh annual consumption,   £638.40 annual cost

If you live in a medium-sized family home, you could save more than £159 by switching from a very old (60% efficiency) boiler to a modern high efficiency (95%) unit.

Boiler efficiency and annual cost in the ‘high’ TDCV category, including large family homes

  • 100% efficiency:  17,000 kWh  annual consumption,  £646.00 annual cost
  • 95%   efficiency:  17,850 kWh  annual consumption,   £678.30 annual cost
  • 90%   efficiency:  18,700 kWh  annual consumption,  £710.60 annual cost
  • 80%   efficiency:  20,400 kWh  annual consumption, £775.20 annual cost
  • 70%   efficiency:  22,100 kWh annual consumption,   £839.80 annual cost
  • 60%  efficiency:   23,800 kWh annual consumption,  £904.40 annual cost

If you live in a large family home, you could save more than £226 by switching from a very old (60% efficiency) boiler to a modern high efficiency (95%) unit.

Efficiency savings summary

  • If you have a flat or a small home, you could save more than £105 per year if you swap a very old boiler for a new high efficiency model
  • If you have a medium sized home, you could save more than £159 per year if you swap a very old boiler for a new high efficiency model
  • If you have a large home, you could save more than £226 per year if you swap a very old boiler for a new high efficiency model

Boiler repair costs

Annual energy costs are not the only thing to consider when your calculating annual savings. You should also think about how much it will cost if anything goes wrong.

Even if you use a reliable Gas Safe Engineer like Add Heat, repairs can be expensive.

At Add Heat, we don’t charge a callout fee. If we manage to fix your fault in the first hour with no materials or spares, we’ll only charge a flat £69+VAT fee.

For relatively simple repairs like a replacement fan or gas valve, you might expect to pay around £150 for parts and labour. To repair a more serious fault, like a broken heat exchanger, your final bill might be closer to £400.

Older boilers are more likely to breakdown compared to newer boilers.

If your boiler has an expensive fault, it is often worthwhile purchasing a new boiler, rather than getting it replaced. A reliable Gas Safe Engineer will be able to offer their advice on whether you should fix or replace your old boiler.

How much does a new boiler cost?

Many people think that replacing a boiler is monstrously expensive.

To maximise the efficiency benefits of a new boiler, we generally advise investing in a high quality unit and a reliable boiler installer. But even this doesn’t need to break the bank. Especially if you take out a boiler finance deal.

The cost of a new boiler can depend on a number of factors, including:

  • The cost of the boiler unit
  • The cost of any necessary system changes, like new radiators or tanks etc.
  • The cost of installation
  • The cost of optional extras like smart controls

If you are doing a like for like boiler replacement – like replacing a Combi system with another Combi system – and there are no broader system changes required, then equipment and labour costs can be much lower.

The cost of a like for like replacement can range from between around £1,500 and £3,500 depending on the size and type of system you use.

The best way to get an accurate quote is to speak to a reliable Gas Safe Engineer today. You can get a quote from Add Heat by calling or emailing us.

New boiler financing

We can offer boiler finance deals for high efficiency Worcester boilers. Buyers can choose from a two year interest free boiler credit agreement or to spread the cost over ten years.

Speak to a member of the Add Heat team to learn more.

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