What Size Boiler Do I Need? – Boiler Size Guide

Here at Hoopla Heating & Plumbing, we understand the complications that can come with sizing a new boiler for your home. You need to consider things such as how much heat and hot water you and your family require before attempting to work out boiler type and size. Understanding what you need from your system will help you to determine the correct boiler size and minimise the stress of boiler installation. It is important to choose your boiler size correctly so that you can have hot water at your disposal and heat your home efficiently. This will also avoid creating high energy costs. At Hoopla Heating & Plumbing, all of our heating engineers are highly trained and experienced in all aspects of boiler installation and repairs. We are qualified to install a range of boiler models including Worcester Bosch, Vaillant, Potterton, Baxi, Vokera and Glow Worm.

What is central heating?

Central heating is the process by which heat travels around your home, usually via a system of pipes coming from your boiler. These pipes can even be under floors or passing through radiators. This heat can be adjusted using a central heating thermostat, time controller or radiator valves to help you find the perfect temperature at the right time. Your boiler is the heart of your central heating system, responsible for creating and sharing heat.

Sizing Your Gas Boiler

A gas boiler heats up the water. It does this by pumping the circulated water in pipework over a series of gas flames. As the water passes the flames, it is heated up, just like water in a pan or kettle. This water serves two purposes in the modern home: central heating and providing hot water. Installing a gas boiler can be more complicated. Gas boilers heat the water in the boiler to the boiling point, using natural or propane gasses. Once the steam is created, it is then transferred using the pipes in your system to the radiators throughout your home. A gas boiler that is too small for your home will not fulfil your needs or heat your home substantially. It will struggle to keep up with demand and therefore, will not provide hot water and heat efficiently. This can lead to expensive emergency plumbing costs. Installing a gas boiler that is too big, will leave you with more than you require and expensive energy bills. When it comes to sizing this kind of system, the process is a little more technical and will involve calculating the square feet in your home.

Gas Boiler Size Calculator

To calculate a gas boiler, you’ll need the size of your house to hand. You were likely informed of this when you brought your home, however, if you do not have this information, you’ll need to measure your home. To begin, measure each of your rooms by beginning in the corner. Measure outwards from the corner, the two walls that meet in this spot and then record the dimensions. Complete this step for each room, once you’ve finished you’ll need to convert all of your measurements into square feet. The next step is to calculate the BTU’s (British Thermal Units).

Your boiler system will need to produce 50BTU per square feet of your home to heat it efficiently. To get a rough size estimate to multiply the measurement of your home by 50.

Combi Boiler System

Combi boilers, short for combination boilers, are one of the most common boilers installed throughout UK homes. This type of system will fulfil both your heating and hot water demands. The size of your combi boiler will be determined by your family size, demand for hot water and the number of bathrooms in your home. The correct sizing is crucial with this type of system to avoid breakdowns and repairs. However, when sized and installed correctly they are practical, versatile systems. Other benefits of the combi boiler include being efficient, easy to maintain and low cost to run. 

Combi Boiler Size Calculator

Before looking at the factors which decide the size boiler you will need, understanding how boiler size is measured first is key. You need the output of the boiler in kilowatts (kW) and not the physical dimensions of the boiler. A kilowatt unit is used to measure how much energy is emitted from a boiler in heat. The more hot water and heat your home requires, the higher the boiler output will need to be. These three factors will determine what size boiler you will need:

  • The number of radiators.
  • The number of bathrooms (with non-electric showers).
  • The number of people in the home (the demand for hot water).

It’s always best to book a consultation with a Gas Safe Registered engineer to size and install your boiler. This will ensure you have the correct system for your needs and that it has been installed correctly.

Other factors can affect boiler size and therefore, it can become complicated. Variables such as heat loss and boiler installation can affect the amount of work your boiler needs to do. To ensure you have the best-sized system for your home, it’s best to contact a reputable engineer. If you need a plumber in the Marlow, Reading, Windsor or wider Henley on Thames area, call Hoopla Heating & Plumbing today.

What Size Boiler Do I Need? - Boiler Size Guide

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