A beginners guide to boiler ratings and efficiency

Tradespeople often use the term ‘boiler efficiency’ when referring to heating systems, but what exactly is it? Believe it or not, an energy-efficient boiler lowers the cost of your monthly bills It also contributes to the well-being of the environment.

Read further to find out more about the boiler efficiency ratings and what makes them so important.

 

What is Boiler Efficiency?

Boilers follow the same ratings as other household appliances the higher the boiler’s rating, the lower its energy consumption, and the lower energy bills you pay each month. 

For example, old boilers didn’t have to comply with current efficiency regulations meaning older boilers consume more gas particularly boilers with permanent pilots or non-condensing boilers.

To help you understand and compare boilers’ efficiencies, there are specific boiler ratings and efficiency charts on every boiler and appliance. 

Boiler Efficiency Ratings

• ErP Rating

ErP stands for Energy-related Products. This directive comes from the European Union and is valid for all member countries. They designed it to drive and increase the improvements in the performance and efficiency of boilers and other water heating systems and to cut down greenhouse gas emissions. 

ErP uses the letters from A to G to rank the efficiency of a boiler or a heating system. A is the highest rating and G the lowest. Nowadays, almost all modern boilers have an A rating. There are also different levels of A rating – A+++, A++, A+, or A. In terms of percentage, A-rated boilers equal to over 90% for efficiency, and the G-rated boilers are equal to under 70% efficiency. 

 

• SEDBUK Explained

When speaking and reading about boiler efficiency, you will also often see ‘SEDBUK’. SEDBUK stands for Seasonal Efficiency of a Domestic Boiler. This is the way all boilers in the UK are rated for easy comparison. This rating also helps determine a boiler’s carbon footprint. 

There are two types, SEDBUK 2005 and SEDBUK 2009. The former uses letters from A to G, where A is the most efficient and G is the least efficient. The latter uses a percentage to show efficiency. Respectively, the higher the percentage, the more efficient the boiler. 

However, the SEDBUK rating isn’t used anymore because the ErP rates replaced it in 2015. While the UK government and boiler manufacturers used the SEDBUK rating, the ErP rating is a European directive, and it’s used throughout the continent. 

 

• How Efficient is Your Boiler?

Are you now wondering what’s the efficiency of your boiler? To find out, check the sticker on the boiler, It can be anywhere on the boiler, the front, the back or on the bottom. All modern appliances have such a sticker which shows the efficiency rating. 

However, if your heating system or boiler is old, it may not have this sticker. Also, you or a plumber may have removed the sticker when the boiler was first installed. In case there’s no sticker, find the model number, and look for the rating online.

There should be an identification plate under the boiler, where the pipes protrude. Look for the brand and the exact model, and KW rating. When you gather this information, you can go to the PCDB database and check the efficiency rating of your boiler.

 

• How to Choose the Most Efficient Boiler

If you’re considering changing your old boiler to a new one, you may wonder which is the most efficient boiler. There are a couple of things you should know and think through before deciding on a new type of water heating system. 

 

To work out the total costs and compare boilers, you have to consider:

• The price of the boiler;
• Installation service and does it need additional parts;
• Running costs yearly;
• Annual service;
• Warranty;

 

Types of boilers

• Combi Boilers – Provide heating and instantaneous hot water, as a rule, the higher the kW rating the greater the flow of hot water.
• System Boilers – Provide heating only the hot water is stored in a cylinder which is heated from the boiler through the coil in the cylinder. System boilers are usually installed in larger homes where there is a higher demand for heating and a requirement for more hot water than a combi boiler can produce.
• Heat Only Boilers – Work the same way as a system boiler the difference been a system boiler has an internal vessel and pump making it a ‘sealed system’ whereas the heat-only boiler allows for the system to be open vented.

 

Boiler KW size is the other crucial metric you need to consider when choosing your replacement boiler the larger the house, the higher the KW rating is required to heat the house efficiently you must also take into account the households hot water requirements. Will a combi boiler provide sufficient hot water? Or do you need stored hot water? If you require stored hot water you will need to allow space for a cylinder as well as the boiler.

How Much Can You Save With an Energy Efficient Boiler

Your boiler is responsible for about 55%-60% of your yearly expenses on energy. If you can reduce the amount of gas used imagine the amount of money you could save each year. To help you with the calculations here is a breakdown, for a boiler that is rated 70% efficient, out of every £1 spent on gas, 30p is wasted energy. With a more energy-efficient boiler, rated at 90%, you lose only 10p for every £1.

How to Improve Your Boiler Efficiency

Understanding the running costs of your boiler is a good reason to want to improve its efficiency. But if you’re asking how to improve your heating's efficiency and if it can be done quickly and cheaply, here we list several things that can help improve the efficiency.

Seasonal Settings

Installing a new, more efficient boiler doesn’t mean you’re set and you can forget about it. The settings on the boiler can affect its efficiency a lot. Naturally, you wouldn’t want to keep the high temperature in your home in the warm months. So, changing the settings on the heating system or boiler seasonally can help you reduce your running costs. If you’re not convinced of your skills to deal with the system, you can hire a qualified Gas Safe/Corgi registered plumber to check them out and fix them. 

Regular Maintenance

To improve boiler efficiency, regardless of type, model, or brand, it’s crucial to have an annual service. The service will highlight any issues with the boiler or heating system and allow you to bring the system to full working order. 

An annual service can determine if the boiler is running at its most efficient. Also, the engineer can advise on the health of the system including the water dirt and corrosion build-up which will reduce the lifespan of the boiler and void the warranty but also make the heating inefficient.

Balancing The System

Hydronic balancing means that all radiators have the exact supply of heat they need. A professional can perform this or you can try it yourself. 

To do this, you must first close all radiator valves. Turn on the central heating and start opening the valves one by one, going further away from the boiler. When all the radiators get warm, this means they are balanced. This simple process can improve boiler efficiency by up to 15%.

Invest in a New Unit

If your boiler is one of the older styles with a permanent pilot or non-condensing it’s probably worth updating to a newer condensing boiler. 

Takeaways

As it is with most things, there are pros and cons to every decision and every type of boiler. Replacing an existing boiler is not a small investment as it’s intended to last for many years. That’s why it’s imperative to consider the boiler efficiency rating and also to think about every detail and aspect of the situation. It’s not a decision to take lightly, so if you’re uncertain about which is the best boiler for your home, you can contact a professional plumber or speak to a member of our staff.