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BTU Calculator
Use our BTU calculator to easily work out what size radiator you will need, by entering information about your room in our calculator.
BTU Calculator
Use our BTU calculator to easily work out what level of BTU and Watt output will efficiently heat your room, in turn allowing you to decide what size radiator you will need:
What Size Radiator Do I Need?
Before deciding on size and style, it’s important that you use our radiator calculator to work out what size radiator you will need to heat your chosen room. If you don’t do this, you may find your radiator is too weak or too powerful for your requirements.
In order to work this out, you need to calculate the BTU as well as the Watts required to heat it effectively.
How to Calculate BTU for a Room
In order to calculate the BTU output that is required, you will need to measure the length, width, and height of your room. You can then use this information in conjunction with our radiator BTU calculator linked above, along with room type, type of window glazing, and how sheltered or exposed it is.
Give your room a name, so you can save it to your Wishlist for easy reference.
Please note: this is a guide only
A radiator with insufficient output may never raise the temperature to the required level. Outdoor temperatures, external walls, insulation, heated adjacent rooms (i.e. above, below, and to the side) all have a contributing effect. The boiler should have sufficient capacity to supply all connected radiators to the sum of their maximum demand. Larger rooms such as living rooms may require more than one radiator, positioned evenly throughout the room. If this is the case, simply divide the required output between the number of radiators needed.
A radiator with insufficient output may never raise the temperature to the required level. Outdoor temperatures, external walls, insulation, heated adjacent rooms (i.e. above, below, and to the side) all have a contributing effect. The boiler should have sufficient capacity to supply all connected radiators to the sum of their maximum demand. Larger rooms such as living rooms may require more than one radiator, positioned evenly throughout the room. If this is the case, simply divide the required output between the number of radiators needed.
What does BTU stand for?
BTU stands for British Thermal Unit.
What is BTU?
A BTU or British Thermal Unit - is the amount of heat needed to increase the temperature of 1lb (one pound) of water by one degree Fahrenheit. This is the imperial measurement, your Installer may work using metric values for this calculation; Watts. Either can be used to select your radiator.
What does BTU mean in relation to radiators?
With radiators, the BTU measurement refers to how much energy is required to heat a particular room. The higher the BTU number is, the greater the radiator’s heat output will be. How effective the radiator will be though depends on factors such as the size of the room and how well insulated it is. A radiator’s ability to transfer heat will depend on its material, size and surface area as well as the water temperature within the system.
Use our BTU calculator to easily work out what size radiator you will need, by entering information about your room in our calculator.
What size radiator do I need?
Before making a purchase, it’s important that you use a radiator calculator to work out what size radiator you will need to heat your chosen room. If you don’t do this, you may find your radiator is too weak or too powerful for your requirements.
In order to work this out, you need to calculate the BTU as well as the watts required to heat it effectively.
How to calculate BTU for a room
In order to calculate the BTU output that is required, you will need to measure the length, width, and height of your room. You can use our radiator BTU calculator below to enter this information, as well as the type of room, type of window glazing, and how sheltered or exposed it is.
Give your room a name, so you can save it to your Wishlist for easy reference.
Please note: this is a guide only
A radiator with insufficient output may never raise the temperature to the required level. Outdoor temperatures, external walls, insulation, heated adjacent rooms (i.e. above, below, and to the side) all have a contributing effect. The boiler should have sufficient capacity to supply all connected radiators to the sum of their maximum demand. Larger rooms such as living rooms may require more than one radiator, positioned evenly throughout the room. If this is the case, simply divide the required output between the number of radiators needed.
A radiator with insufficient output may never raise the temperature to the required level. Outdoor temperatures, external walls, insulation, heated adjacent rooms (i.e. above, below, and to the side) all have a contributing effect. The boiler should have sufficient capacity to supply all connected radiators to the sum of their maximum demand. Larger rooms such as living rooms may require more than one radiator, positioned evenly throughout the room. If this is the case, simply divide the required output between the number of radiators needed.
What does BTU stand for?
BTU stands for British Thermal Unit.
What is BTU?
The British Thermal Unit is the amount of heat needed to increase the temperature of one pound of water by one degree Fahrenheit.
What does BTU mean in relation to radiators?
With radiators, the BTU measurement refers to how much energy is required to heat a particular room. The higher the BTU number is, the greater the radiator’s heat output will be. How effective the radiator will be though depends on factors such as the size of the room and how insulated it is.