Boiler Efficiency

To increase your boiler efficiency you should consider changing your back boiler as they are really inefficient

You have an old boiler, located behind a wall and fire front, that is inefficient and should be replaced. Back boilers provide hot water and sometimes heat radiators. They are usually fitted behind an open fireplace or stove and are not efficient as a lot of the heat they produce is lost up the chimney.

You Need to Upgrade From a Standard-efficiency Boiler to a High-efficiency Boiler

You have an old boiler that isn’t working efficiently. Recent changes in the law mean all new gas boilers fitted in the UK should be high-efficiency condensing models. This simply means that the boiler will extract more energy from the fuel and turn it into usable heat. Old standard-efficiency boilers can waste over a third of the energy they produce. Modern high-efficiency boilers can be 90% efficient. Upgrading to a condensing boiler can save as much as 40% on your heating and hot-water bills.**

This boiler is very efficient and has a fantastic SEDBUK rating

The boiler your installer is showing you is a very efficient model. SEDBUK stands for Seasonal Efficiency of Domestic Boilers in the UK. It’s a Government database that provides a simple way of comparing the energy efficiency of boilers. The SEDBUK rating shows the efficiency of boilers as a percentage. The most efficient boilers today are rated as being around 90% efficient.

  • 90% and above A
  • 86% – 90% B
  • 82% – 86% C
  • 78% – 82% D
  • 74% – 78% E
  • 70% – 74% F
  • Below 70% G

Calculating Boiler Efficiency – What You Need To Know

A boiler system is an important part of any home, mainly because it performs an important function. But, boiler systems also come with their fair share of expenses, which can be curbed if you make smart decisions. The first step, towards efficiency, is by getting an energy efficient boiler installed in your home. But, how does one know if the boiler they have installed in their home is efficient or not? Boiler efficiency is a term that is used to describe the difference between the energy that is supplied to the boiler in regards to the output of energy that’s received from the boiler.

Calculating Boiler Efficiency

Calculating the efficiency levels of a boiler system all boils down to two main factors, which are; thermal efficiency and combustion efficiency.

Combustion Efficiency

Combustion efficiency of a boiler has got to do with the burner’s ability to burn fuel. There are two parameters when it comes to combustion efficiency, which are, the quantity of un-burnt fuel in the exhaust and secondly, the excess oxygen levels that are trapped in the exhaust. As the excess air increases in the boiler the amount of un-burnt fuel within the exhaust also decreases, which results in a decrease of un-burnt fuel losses, but an elevated enthalpy loss. This is why it is important to maintain a balance between the un-burnt fuel losses and the enthalpy losses. Combustion efficiency is normally higher for liquid and gas fuels as compared to solid fuels.

Thermal Efficiency

The thermal efficiency of a boiler system is an indicator of the efficiency of the heat exchanger within the boiler, which is responsible for transferring heat energy from the fireside to the water side of the boiler. Thermal efficiency of a boiler can be negatively affected by the amount of soot and scale formations within the boiler tubes.

Direct and Indirect Boiler Efficiency

Apart from combustion and boiler efficiency, the level of efficiency of a boiler system also depends on other factors. The other parameters include radiation losses, on-off losses, blow down losses and convection losses etc. There are two methods of determining the levels of efficiency of a boiler; direct method and indirect method.

Direct Method

In this method we calculate the efficiency of a boiler by using a basic formula:

η = (Energy output) / (Energy input) X 100

Using this simple formula, we divide the total energy output by the total energy input that’s provided to the boiler, which is then multiplied by 100.

In-direct Method

The indirect method of calculating a boiler’s efficiency is by finding the individual losses that are taking place in the boiler and then subtracting those with the sum from 100%. In this method, you need to find out the magnitudes of all of the measurable losses that have occurred in your boiler system. All of the losses are added first and then subtracted from 100% to find the current efficiency levels of a boiler.

Boiler Efficiency

Maintaining optimum efficiency levels of your boiler is necessary for cutting down energy bills. It should also be noted that a boiler’s efficiency does not remain fixed and there are large variations from ideal values taking place during the course of a boiler’s operation. This is why real-time monitoring is so important when it comes to determining the efficiency levels of a boiler system.