How efficient is my gas boiler?
What does a boiler’s energy efficiency mean?
You rely on your boiler for hot water all year round and especially in the colder months for heating.
Doing all that takes a LOT of energy – over half the average home’s total energy use, in fact. So the efficiency of your boiler has a big impact on your finances as well as your carbon footprint.
A boiler’s efficiency is the amount of energy that actually goes into heating your home, rather than being lost or wasted.
If your boiler is 90% efficient, only 10% of the energy is lost.
But if your boiler’s efficiency is 70%, you’ll lose 30%.
What is ErP?
ErP stands for ‘Energy-related Products’. It’s the European rating system for boilers and other heating appliances.
Every new boiler has an ErP energy label, which ranks its efficiency from A-G. By law, all modern gas boilers in the UK are A-rated, which means they’re highly efficient.
Every new boiler has an ErP energy label, which ranks its efficiency
from A-G. By law, all modern gas boilers in the UK are A-rated, which
means they’re highly efficient.
What is SEDBUK?
There are two different versions of the SEDBUK rating system, which stands for ‘Seasonal Efficiency of a Domestic Boiler in the UK’.
SEDBUK 2009: The 2009 system gives each boiler an exact percentage score. This is what to look for if you really want to get into the detail, but the difference of a few percentage points won’t have a massive impact on your bill. The big savings come from swapping an old boiler for a new one.
SEDBUK 2005: This is the old system still used by lots of manufacturers. Like ErP, it rates boilers from A to G. A-rated boilers score over 90% for efficiency, while G-rated boilers come in under 70%.
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Why Choose us?
You can rest easy knowing that your boiler, service & repair needs are in safe hands with iSafe gas. We offer a wide range of benefits to ensure you never have any worries about being left out in the cold!
Watch how we ensure you're getting the right boiler for your home.
We install boilers from the leading manufacturers including Vaillant, Worcester Bosch, Viessmann, Alpha & Ideal.
Follow our sales manager James as he accompanies our engineer on a recent new boiler fitting for one of our customers.
Hear from one of our happy customers who had a brand new boiler fitted.
Why are new boilers more energy efficient?
In the UK, a 2007 law made it compulsory for all new boilers to be ‘condensing’ boilers. This is a modern design that’s much more efficient than the old style of boiler.
Condensing boilers use the warmth from the hot gases expelled in the flue, rather than just letting all that heat go to waste. A condensing boiler will always be at least 90% efficient, or even more.
So, if you’re wondering how efficient your home’s boiler is, the answer is probably ‘very’ – but only if it was bought and installed recently.
Why should you upgrade an old boiler?
Older boilers are much less efficient than modern condensing boilers.
The energy efficiency of an older boiler can be as low as 60% – which is a G rating. With a G-rated boiler, 40% of the energy you pay for is going to waste rather than heating your home.
That means upgrading an old boiler to a newer, more efficient model is a great way of saving money.
And because more energy efficiency means lower CO2 emissions, it’s good for the planet too.
How much can I save with a new boiler?
Source: Energy Saving Trust
Figures are calculated using fuel prices as of April 2022. These are estimated figures based on installing a new A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator controls (TRVs) in a gas heated home from an older boiler with a programmer and room thermostat. Savings will vary depending on the size and thermal performance of your home.
What type of boiler is most energy efficient?
If you’re choosing between a conventional, combi or system boiler, none of them is necessarily more energy-efficient than the others. But picking the right one for your property and family size will mean you’re using it in a more energy efficient way.
For example, if you’re in a small property with a small family, a combi boiler might be your best option. A combi boiler makes hot water on demand, so you won’t be storing hot water that never gets used.
But if you have a large property and a big family, a combi boiler won’t be the most energy-efficient choice. A system or conventional boiler is more likely to meet all your needs while helping to keep the bills as low as possible.
Is boiler size important for energy efficiency?
Yes, choosing the right size boiler for your property and your family has a big impact on energy efficiency.
We will do a full heat loss calculation at our survey to get the correct sized boiler for your home.
When we talk about boiler size, we’re really talking about its heat output. This is measured in kilowatts (kW).
If your boiler isn’t big enough, it will struggle to provide the heat you need. But if it’s too big for what you actually need, you’ll end up wasting a lot of energy in your heating and hot water.
Looking for a new boiler?
If you need advice on anything to do with boilers, our team at iSafe are always here to help.
You can book a free appointment and one of our heating advisors to come and look at your boiler and central heating system. They’ll talk you through the best options for your home and give you a fixed price quote.
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Frequently Asked Questions
Absolutely. We have a full section on the website which will show all of this for you. We are very proud of them as nothing beats a happy customer – Reviews. Word of mouth and recommendations is very important to us so we always ask for as much feedback as possible.