How Efficient Are Condensing Boilers?

All new boiler installations in the UK are completed using a condensing boiler. By recycling waste gases, they’re able to improve efficiency in comparison to a non-condensing equivalent.

That means less energy consumption, reducing your carbon footprint, and a huge reduction in energy bills.

But, due to the fact condensing boilers are sealed, they’re much safer too.

How Much More Efficient Are Condensing Boilers?

Expect to see energy efficiency rise by somewhere in the region of 10-12%.

However, the exact percentage of improved efficiency will depend on the boiler you’re currently using, and the unit you’re upgraded too.

How Can I Calculate Improvements In Efficiency?

The first step is to determine what efficiency rating your boiler is. For example, a G-rated boiler will only operate at around 70% efficiency. This rises to around 82% for a D-rated boiler.

Let’s compare that with A-rated boilers, which are around 90% efficient. But, due to a new legislation called “Boiler Plus”, the combination of a boiler and heating controls, need to operate at 92% or higher.

So, even moving from a D-rated to A-rated “Boiler Plus” compliant package, would see a rise of 12% efficiency. Moving from a G-rated boiler, with just 70% efficiency? Your savings could be in excess of 22%.

How Much Money Will An A-Rated Condensing Boiler Save You?

Savings of up to £840 per year on your energy bills are possible. This would be the rough calculation for a large detached house, upgrading from a G-rated boiler, to an A-rated boiler.

Further Reading / Sources

You can see a full guide to boiler ratings and their efficiency at the Energy Saving Trust’s website.

There’s also an indication of a 30% reduction in energy consumption on Vaillant’s (a leading boiler manufacturer) website.