Blog Home Page

Explaining the BTU Calculator

btu calculator explained

Welcome back to the Only Radiators blog, where this week we shall demystify the elusive BTU.

We’ll kick things off by breaking down what the unit itself is, then move on to harnessing the best function of our BTU calculator to improve your experience when browsing our expansive online store by allowing you to filter your radiator search down to only the most relevant units.

So, let’s get kick things off with the question we hear oh so often.

What does BTU Stand for?

“British Thermal Unit” - a traditional unit of heat defined as the amount needed to raise one lb of water by one degree Fahrenheit. If you want an idea of what this means in real world terms, a single BTU is approximately 1.06 kJ (kilojoules) or the heat produced by burning a single wooden kitchen match!

So now we’ve got the definition out of the way, let’s get down to business.

How Many BTU to Heat a Room?

“How many BTUs do I need to heat my house?” is a question we hear just as much, and the answer boils down to the key elements of the room we wish to heat.

A room’s BTU requirements depend on factors such floor space and vertical height, whether or not the room possesses external walls, the amount of wall space covered by windows and their glazing, and so on.

What does the room have positioned below – a heated floor, heated room, wooden floor, or something else? And what about above – a slate, thatched, or wooden roof, and what thickness of insulation?

BTU calculations account for the heat required to fill a room as well as amount of heat that can escape. Better insulation equals less BTU, while the same is true for the opposite.

Simple, really!

Calculating BTU

To measure the BTU of your old radiator you can use simple dimension graphs like this, and to discover the BTU required to heat a room with a new radiator you can use our handy Only Radiators BTU calculator.

Using Our BTU Calculator

With just a tape measure (or one of those cool laser tools if you’re feeling futuristic!), a room to measure and a few minutes of your time, you’ll have successfully narrowed down your search to only the most relevant radiators, saving you money, time and effort, and enabling you to peruse our massive online store at your uninterrupted leisure.

Let’s take you through it, step by step.

Step 1 – Room Dimensions

First, you need to measure the length, width and height of the room you wish to heat. You can then input these measurements into the BTU calculator in either metres or feet.

Step 2 – Further Room Info

Next, the BTU calculator requires a bit more info regarding the layout and construction of your room.

How it fits into the rest of the home, what type of glazing the windows offer, and how exposed to the room is to the elements.

Answer these by selecting room type, window type, and level of shelter.

Step 3 – BTU Results!

And just like that, you have your answer.

Our BTU calculator provides you with two measurements – BTU/hr and Watts required. These are the only two measurements you will need, and the two measurements that you will find reported for every radiator in our online store.

The minimum output is the most important number here. Providing that the BTU output of the radiator that you choose equals or is greater than the minimum value provided by the calculator, you’ll have enough heat to sufficiently heat your room.

btu calculator process

Browsing Only Radiators by BTU

Now that you know how to calculate how many BTUs to heat a room, you can hone in your search to only the most relevant radiators available.

To browse our radiators by BTU output, first arrive at any section of our expansive online store, for example the vertical radiators main page, and note the assortment of search criteria running down the left side of the page.

As well as the opportunity to browse our selection by dimension, colour and more, we enable you to search specifically by:

  • BTU: the amount of BTUs pushed out by the radiator per hour.
  • Watts:  the standard for specifying the size of electric heater required to heat a room.

The general rule for is 10 watts of power required per square foot of room being heated. Stay tuned for an article on what’s what’s what with watts, though for now let’s return to our beloved BTUs.

Flexibility of BTUs?

Don’t despair if it turns out the radiator you simply must have is not powerful enough to fill the room in question with heat.

A radiator with too low BTU output may not be able to efficiently heat a room alone, though if it’s absolutely necessary, about 10% below will usually be fine. Remember that the measurement gained from our BTU calculator is an all-encompassing reading, accounting for all possible heating elements within the room. While you would want to avoid the need to line up six extra electric heaters come winter, you certainly can select two or three smaller radiators to meet your room’s BTU requirements. There’s really no top-end when it comes to BTU specification so you needn’t worry about overspending on a juggernaut of a radiator, that’s where thermostatic valves come in handy, you can just turn them down to find the perfect heat.

All this is why relying upon our BTU calculator actually increases your flexibility in buying a new radiator, rather than restricting it.

Once you have your BTU calculation in mind, your search will become far simpler, and you won’t waste money on running juggernaut rads at half-power or lining up six electric heaters to top up an exposed room come winter.

Pushing the Tempo

You can increase or decrease a radiator’s BTU in a few ways, such as increasing the temperature of the water that you run through the system. While the general heat used is 50°C, this can be upped to 60°C with a minor adjustment that will boost your radiator BTU.

And when it comes to the material of the radiator you have in mind, this also has a big bearing upon the product’s BTU output. If you require the biggest heat from the smallest possible radiator, one of our aluminium models is the only way to go.

BTUs and You

Simply put, BTUs are the universal unit for the measurement of radiator efficiency.

Think of them as a radiator sizing guide and sure-fire path to discovering the right sized radiator for your room.

Now go enjoy browsing our site with an even better idea of the radiator that will perfectly suit you!

And if you need any advice or help regarding what we’ve just covered, then give our expert team a call or stop by the store.

Your Leading Heating Source

As always, keep checking up on the Only Radiators blog time and time again for industry-leading home heating ideas, and sign up to our newsletter for exclusive news, money-saving tips, competitions and much more! Return to the Knowledge Base

Leave a Reply

Your email address will not be published.

You have no items in your shopping Basket.