Heat Output Requirement Calculation

Using the below calculation tool you can easily deduct the requirements for most rooms. Note that towel warmers are not intended to replace like for like the performance of a panel radiator as they have much lower surface area and convection capabilities.

Once you have the figure required for each room, any combination of products and different sizes is possible until you achieve the required output figure.

Heat Output Calculator

Heat Output Calculator

What are BTU’s

BTUs are ‘British Thermal Units’, the unit in which radiator efficiency is measured. Factors such as room dimensions, windows and wall type are used to calculate the required outputs of radiators, in order to adequately heat a room.

How do I calculate the BTUs for my room?

Our BTU Calculator is an accurate guide as to what level of BTU and Watt output will efficiently heat your room. Please note: the calculated figure is for the combined heat output of all radiators and/or towel rails in your room (larger rooms may require more than one).

  • Dimensions of the Room Feet Meters
    Width: Length: Height:
  • Select the Room Type
    Dining Room/Lounge Bedroom/Bathroom Kitchen/ Common Area
  • Additional Factors to be taken into consideration. Does the room have:
    North Facing Wall French Windows Double Glazing

Manual Output Calculation

Step1

Multiply the room length in metres by the room width in metres by the room height in metres (LxWxH) to calculate the total cubic volume of the room.

Step 2

Multiply the room cubic volume by 45 to give you the Watt requirement.

Step 3

Combine all of the applicable correction factors from the list below and then apply the total percentage to the Watt requirement calculated in Step 2.

-25% Upstairs bedrooms

-20% Cavity filled walls

-10% Solid floor

-05% Double glazing

+10% Un-insulated cavity walls

+10% North facing wall

+15% Patio doors or French doors

+15% Two outside walls

+15% No loft insulation

+20% Ceiling height above 3 metres

+40% Three outside walls

PLEASE NOTE THAT THESE ARE APPROXIMATE CALCULATIONS FOR GUIDANCE ONLY

Frequently Asked Questions

General

Q. How long is the warranty on Kudox products?
A. Our diverse product range necessitates individual warranties. Our equally diverse customer base also have their own specific warranty requirements and we do our best to accommodate these. Please check the warranty details with your place of purchase.
Q. What heat output do I need to heat my bathroom?
A. There are many online calculators you can use to calculate your requirement and these can be found by searching 'BTU Calculator'. Once you have calculated your requirement we would always recommend choosing a product that is over-sized because you will be hanging wet towels on it.
Q. How can I keep steel products free from corrosion?
A. In the same way that an unpainted car would rust, all steel radiators and towel rails would rust if the central heating system contained solely water. It is therefore essential that the system is properly cleaned and then protected. After installation, the entire central heating system must be thoroughly flushed with a ‘Domestic Water Treatment Association’ (DWTA) approved central heating cleanser. Following cleansing a DWTA approved central heating protector must be added to the central heating system. Kudox recommends to use Fernox Preventing corrosion with Fernox

Electric Towel Rails

Troubleshooting Procedure

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Q. How long is the warranty on Kudox products?
A. Our diverse product range necessitates individual warranties. Our equally diverse customer base, also have their own specific warranty requirements and we do our best to accommodate these. Please check the warranty details with your place of purchase.
Q. I have purchased an electrical element kit; I think I also need an additional blank plug though?
A. Our electrical element kits include a T piece and a blank plug (usually screwed into the T piece so that it doesn't get lost). If you are making the product electric only you do not need the T piece. The blank plug is required for the other bottom thread where a radiator valve would normally be fitted. If you are making the product dual fuel you do not need the blank plug.
Q. What liquid is inside the pre-filled electric towel rails?
A. Our pre-filled electrical towel rails are 90% full to allow the liquid to expand when heated. The liquid is Henkel Technologies Frostox SF-D12 Glycol based corrosion inhibitor and antifreeze mixed with water. The mixture ratio is approximately 15% SF-D12 and 85% water.
Q. Does a towel rail perform exactly the same when an electrical element kit is used?
A. No, when an electrical element is used to heat a towel warmer you will not get identical performance as you would connected to a central heating system. There is no circulation and it will therefore take longer to heat up and will be noticeably hotter near the element. After 1 to 2 hours continuous use the heat would have spread but there will still be temperature variances across the surface but this is not a fault. The output will also be restricted to the element rating.
Q. Can I fit an electrical element larger than the one that Kudox recommends?
A. No, it is dangerous to exceed our recommendations.
Q. I’ve purchased an electrical towel rail but it just trips the RCD, is the towel rail faulty?
A. Not necessarily, please contact support for the fault finding advice sheet.

Central Heating Towel Rails

Q. How long is the warranty on Kudox products?
A. Our diverse product range necessitates individual warranties. Our equally diverse customer base, also have their own specific warranty requirements and we do our best to accommodate these. Please check the warranty details with your place of purchase.
Q. Does a towel rail perform exactly the same when an electrical element kit is used?
A. No, when an electrical element is used to heat a towel warmer you will not get identical performance as you would connected to a central heating system. There is no circulation and it will therefore take longer to heat up and will be noticeably hotter near the element. After 1 to 2 hours continuous use the heat would have spread but there will still be temperature variances across the surface but this is not a fault. The output will also be restricted to the element rating.
Q. Can I fit an electrical element larger than the one that Kudox recommends?
A. No, it is dangerous to exceed our recommendations.
Q. Can I fix your radiators to plasterboard?
A. Obviously the bigger the radiator the heavier it is and the stronger the wall fixing needs to be. Ideally the brackets should be fixed to timber studs or noggins but if this is not possible suitable specialist plasterboard fixings should be obtained.
Q. What heat output do I need to heat my bathroom?
A. There are many online calculators you can use to calculate your requirement and these can be found by searching 'BTU Calculator'. Once you have calculated your requirement we would always recommend choosing a product that is over-sized because you will be hanging wet towels on it.

Convector Panel Radiators

Q. How long is the warranty on Kudox products?
A. Our diverse product range necessitates individual warranties. Our equally diverse customer base, also have their own specific warranty requirements and we do our best to accommodate these. Please check the warranty details with your place of purchase.
Q. Can I fix your radiators to plasterboard?
A. Obviously the bigger the radiator the heavier it is and the stronger the wall fixing needs to be. Ideally the brackets should be fixed to timber studs or noggins but if this is not possible suitable specialist plasterboard fixings should be obtained.
Q. What heat output do I need to heat my bathroom?
A. There are many online calculators you can use to calculate your requirement and these can be found by searching 'BTU Calculator'. Once you have calculated your requirement we would always recommend choosing a product that is over-sized because you will be hanging wet towels on it.