Non-condensing boilers are an older type of heating system that were commonly installed across the UK until about 20 years ago. They are not very efficient and can be costly to run because they lose a lot of heat through the gases that escape out of the flue (a pipe that releases waste gases). These old boilers are only about 70–80% energy efficient. In comparison, modern A-rated condensing boilers like the Ideal Logic+ Combi and Baxi 800 Combi are over 94% efficient. The big difference is that condensing boilers have an extra heat exchanger. This extra part captures heat from the waste gases and uses it to start warming the water. This means less fuel is needed to fully heat your home, saving energy and money.

A combination boiler (or combi boiler) is a small, all-in-one system that provides both heating and hot water. Unlike back boilers, it doesn’t need a separate water tank or hot water cylinder. Instead, it heats water directly from the mains whenever you turn on a tap or shower. This means you get instant hot water without having to wait for a tank to warm up.

Best Combi Boilers in the UK

• Worcester Bosch Greenstar 4000: Quiet, dependable, and energy efficient (A-rated).
• Ideal Logic+ Combi: Small, affordable, and saves energy.
• Baxi 800 Combi: Simple to install and comes with a long warranty.
• Ideal Vogue Max: High quality with smart controls for easy use.

The ECO4 scheme is the latest version of the UK government’s energy efficiency grants. Launched in 2022 and funded by the UK’s major energy suppliers, it is designed to help households improve their energy performance. The scheme focuses on homes with low energy efficiency ratings (EPC bands D, E, F, and G) or families who receive income-based benefits. Through ECO4, eligible households can receive support such as a free boiler grant. This includes the option to replace your non-condensing gas boiler with a new A-rated combi boiler grant, helping to lower energy bills and keep your home warmer especially as heating costs continue to rise.

Do you qualify?

• You need to own your home.
• Your current boiler should be old, inefficient, or not working properly. ECO4 usually helps replace boilers that are over 20 years old, especially non-condensing ones.
• To qualify, your home must have a low Energy Performance Certificate (EPC) rating—D, E, F, or G. If your home is already quite energy efficient (EPC A to C), you likely won’t be eligible.
• You must have gas supply or be willing to get connected.

You can check if you qualify using Heat1 online tool. After that, a certified surveyor will visit your home for a quick check. If approved, your new boiler is usually installed within a few days.

Save Money: Get a new, energy-efficient boiler through a grant—free of charge.
Boost Efficiency: Enjoy more heat while using less energy.
Dependable Heating: Modern Baxi combi boilers are durable and rarely break down.
Eco-Friendly: Use less energy and reduce your carbon footprint.

If you switch from an old, inefficient non-condensing boiler to the highly efficient Ideal Vogue Max Combi boiler, you could slash your energy bills and enjoy big savings. This premium combi boiler is expertly designed to save energy by heating water only when you need it, unlike older gas boilers with tanks that waste energy keeping water hot all day. Depending on your home and usage, this upgrade could save you up to £300 a year!

In the UK, new combi boilers usually cost between £500 and £3,000. But here’s the best part — If you qualify, you could get a brand-new combi boiler installed for free through the ECO4 government grant with Heat1, making it an easy, affordable, and smart choice for your home.

Heating accounts for over 60% of energy use in UK homes—most of which is powered by gas. Upgrading from a non-condensing boiler to a modern A-rated condensing model can significantly reduce your home’s carbon emissions. Combi boilers are more efficient because they use less energy to heat your home, which means they release fewer harmful gases into the atmosphere compared to older, non-condensing systems.

Environmental Benefits:

• Save up to 1.5 tonnes of CO₂ per year
• Reduced dependence on fossil fuels
• Improved air quality, especially in urban areas

By participating in the ECO4 scheme, you’re not just cutting energy costs—you’re helping build a greener, more sustainable future.

Applying for a free A-rated combi boiler with heat1through the ECO4 scheme is straightforward:

Step-by-Step Application Process:

Eligibility Check: Use Heat1 free tool to see if you qualify in just 60 seconds.
Free Survey: If you qualify, Heat1 will arrange a free survey where their experts check your boiler and home.
Approval & Scheduling: Once the survey is done and you’re approved, they will set a date for the installation.
Installation: On the scheduled day, their engineers will remove your old gas boiler and install the new one.

If you’re still relying on a non-condensing gas boiler, there’s never been a better time to upgrade. Through the government’s ECO4 scheme, you could receive a brand-new boiler grant at no cost. Not only will you reduce your energy bills and keep your home warmer, but you’ll also boost its overall comfort and value. Don’t wait—check your eligibility now at heat1.co.uk and take the first step toward a greener, more energy-efficient home.