Did you know that heating could account for around 55 per cent of what you spend every year on your energy bills? So, if you want to keep your household costs to a minimum, it makes sense to pay attention to the efficiency of your boiler.

By selecting the right heating system for your home, and making sure it runs as efficiently as possible, you could save yourself a lot of money in the long term. You will also be doing your bit to limit your carbon footprint and help the environment.

Is My Boiler Energy Efficient

What is the efficiency rating of my boiler?

One of the easiest ways to check the efficiency of a boiler, whether it’s one you already have or one you’re thinking of getting, is to look at its efficiency rating. By law, all boilers must have one of these ratings. Since 2015, new models have been assigned ratings determined by the Energy related Products (ErP) directive. A is the most efficient grade and G is the least efficient, and boilers can be rated differently for their heating and hot water performance.

Before the ErP directive, boilers were scored on the Seasonal Efficiency of a Domestic Boiler in the UK (SEDBUK) system, which assigns them a grade from A to G and an exact percentage score. For example, an A-rated boiler will get an efficiency score of over 90 per cent, while a G-rated model will get a score of under 70 per cent.

Modern boilers should all have a good efficiency rating. This is in part because they are condensing models, meaning they capture some of the energy that would otherwise be wasted in the form of hot gases escaping from the flue. They use this captured energy to heat water returning from the central heating system. As a result, they don’t require as much heat from the burner, saving fuel and making them more efficient to run.

However, if you have an old model, you may well find that it has a poor efficiency rating. Because of this, you might be paying much more than you need to for your heating and hot water.  

What is the most energy efficient boiler?

If you’ve decided it’s time to replace your existing boiler with a new one, you’ll no doubt want to make sure you get a highly efficient model. However, it’s important to be aware that there is no single best solution for all households. The most energy efficient and practical boiler for your home will depend on a range of factors. 

Here, we break down what you should consider when you’re trying to find the right boiler for your property.

Fuel

If you have access to mains gas, the cheapest and most efficient boiler for you will almost certainly be a mains gas powered model. This is guaranteed to cost you less than oil, LPG and house coal. 

If you’re not already on the mains, you may want to contact the company that owns the gas network in your area to see if it’s possible to get connected. Bear in mind that this company might be able to help you with the cost, and in some cases the work is fully funded.

Looking to replace your gas boiler?

Type

While you can be confident that any new boiler you choose will be designed to be highly efficient, you should think carefully about the particular type of boiler you select for your home. There are three main types available. These are combination (combi), conventional and system models.

Combi boilers are highly popular, making up more than half of all new boilers being installed in the UK. Designed to be space saving because they don’t require a hot water cylinder or separate pump, they heat water directly from the mains, giving you hot water on demand. In contrast, conventional boilers need a cold water storage tank to feed a hot water cylinder. They are typically found in older homes and are often used when there is a high demand for hot water or multiple bathrooms. They can also be a good option in areas where water pressure is low. However, they don’t deliver instant hot water. Instead, water must be preheated.

System boilers operate in a similar way to combi models in that they heat water directly from the mains and don’t use a cold water storage tank. However, they do use a storage cylinder and they can deliver a constant supply of hot water simultaneously to any number of taps. They are also compatible with solar water heating solutions, meaning they can deliver lower energy bills, as well as environmental benefits.

When asking yourself which type of boiler will be most efficient and practical in your home, you’ll have to take into account how you use your heating and hot water, as well as the size and layout of your property.

Model

Once you’ve decided on the type of boiler you want, you’ll need to pick a model. Make sure you pay careful attention to the energy efficiency rating. By selecting a highly efficient model, you stand to save yourself a considerable amount of money over the lifespan of the boiler. You’ll also be doing your bit to reduce your carbon emissions.

It’s important to research your options, and note that while it may save you a little money upfront, going for the very cheapest model available could actually end up costing you more overall if it is less efficient that alternative options. Bear in mind that if you are considering a storage cylinder, they also have an efficiency rating based on their heat retention and loss results.

How can I improve the efficiency of my boiler?

If you’re wondering how to improve boiler efficiency, it pays to bear the following suggestions in mind.

Invest in a newer, better model

When you’re dealing with an old, inefficient and potentially unreliable boiler, your best option may be to cut your losses and replace it with a new model. By swapping an outdated design for new condensing boiler, you stand to make major savings on your energy bills. Also, you won’t have to worry about your heating system breaking down.

Know your heating controls

It’s not just the model of boiler you have that impacts on efficiency. How you use it will also have a bearing on costs. There are now a wide range of heating controls available that can help you to control your bills. Ideally, the complete set of controls for your system will include a boiler thermostat, a programmer or timer, a room thermostat and thermostatic radiator valves.

By making sure you have these controls and getting to grips with how to use them correctly, you could significantly reduce your running costs. For example, turning your room thermostat down by just one degree could save you around £60 a year.

Ensure hot water cylinders are well insulated

If you have a boiler that uses a hot water cylinder, make sure this is well insulated. New models are factory insulated, but if you have an old one, topping up the existing insulation to 80mm could help you to save around £20 a year. Also, if you’re buying a new cylinder, make sure the one you go for is no bigger than you need it to be.

Use hydraulic balancing

Hydraulic balancing ensures that all radiators are supplied with exactly the amount of heat they need, and it can increase the efficiency of a heating system by as much as 15 per cent. The easiest way to do this is to call in a heating engineer. However, you could carry this process out yourself.

To do this, close the valves on your radiators that are located on the opposite side to the thermostatic radiator valves, or that control the flow of water into the radiators. 

Do this to each of the radiators in your home. Then, ensuring that your central heating is turned on, start with the radiator closest to your boiler and slowly open the flow valve until the radiator is warm and you can feel a noticeable difference in temperature between the flow pipe and the pipe at the other end of the radiator. 

Continue this process with the rest of your radiators, moving further and further away from your boiler until all of your radiators have been adjusted. Once you’ve done this, your heating system should be balanced.

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