How Your Radiators Could Be Misleading You About Heating

Whenever you have your home heating on, are you 100% confident you know exactly what your radiator is doing? I don’t mean, do you know how your radiator works but are you confident you know at what capacity it is heating a room and whether it meets the heating requirements of your space. 

In this short blog post, I want to address two areas that I believe most people overlook or don’t fully grasp when talking about radiator heat output. These are the valve ratings you will find on radiators, and the BTU rating you need to figure out much heat a radiator should produce. Having a better knowledge of both can stop anyone from wasting energy or money when shopping for new radiators and heating their homes.

Radiator Valve Confusion

Please note that I’m going to be talking about thermostatic radiator valves and not manual valves. If you are unsure which is which, manual valves look like a small-cap while thermostatic valves will have a number or gauge on the side which you used to operate the valve. 

So what is it about radiator valves that I think most people aren’t aware of? It comes down to this simple scenario; do you always have the valve set at the maximum value (5) or do you play about with where the meter sits?

If you have every valve in your home set at the maximum, you are not heating your home correctly. You may be wondering how this could be, so let me explain. Your thermostatic valve does not work off the temperature of the radiator, but what it assumes you want the temperature of the room to be. Most thermostatic valves will come with a temperature table on the packaging. Somewhat annoyingly, it tends to be the case that most of us will be living somewhere which already has valves in place, and we are not sure what the temperature could be. There is no steadfast rule, but it is safe to assume that when you have a thermostatic valve set to maximum, you are telling that valve you want the room to be at least 30 degrees Celsius.

When your radiator is on, it should not be blisteringly hot to the touch all the time. The radiator’s function is to regulate heat within a space, and the valve is attempting to match your desired temperature with an element inside the valve head. So if you were to have a radiator valve set to five, you would continually use fuel as your radiator thinks it needs to reach a scorching temperature. Learn more here about radiators.

In most cases, your radiator valve needs to be around two or three / the middle of the heating range; which is roughly 17 to 19 degrees Celsius. I would recommend you set all your radiator valves to this level and run your heating as usual. If you find that your room feels warm and is roughly how you would usually want it to be, then it’s a sign you don’t need your valves turned up fully. 

BTU Confusion

I am writing this from a UK perspective, and as such, I need to address BTU ratings. BTU Stands for British thermal unit and is a rough rating to help a plumber figure out what size an iPad or radiator needs to provide to heat a room. Every room will have a unique BTU rating as it has to take into account every square inch of space.

Luckily, it is quite easy to calculate the BTU for any room. All you need is a BTU Calculator, like the one you’ll find at Trade Radiators. All you need to do is get a tape measure and jot down the length, height, and width of the room, as well as the space windows, may take up. Once you provide that information to a BTU Calculator, it will give back a rough rating which will give you an idea of what size of the radiator to get. I find it to be especially helpful as it can prevent someone from purchasing too big a radiator. You would not want this; otherwise, you would end up with a radiator that uses too much energy, i.e. wastes money on fuel.

I also recommend buying a radiator which has a rating roughly 100 or 150 above your recommended BTU, as it’s more practical to have a radiator you can turn down and adjust rather than one which will never quite hit the level it needs to.

Good luck With Your Radiators

I hope you find this information helpful and it allows you to better control heating output in any room. Remember that as long as you’re not pushing radiators to their maximum output, you are allowing your radiators to work at an optimal level.

Khuwalid Khalid
Khuwalid Khalid
Contact at