Alpha - Column Radiator Feet - 4 Column Black

Delta (Δ) Ratings Explained

What is a Delta (Δ) Rating?

When discussing heat outputs, the Delta rating is the difference between the temperature of the water inside the heating system and the desired temperature of the room.

What does the value represent?

In simple terms, this value is about heat loss. Heating a room only works, if the radiator output exceeds the heat loss of the room.

We use this calculation to make it easy to choose a radiator that will have a heat output that exceeds the heat loss of the room when connected to your heating system type.

If you don't know the room heat loss, you can use our calculator to find out.

What Delta Rating should I use?

• Δ50 = Gas boilers before 2005 / Oil boilers before 2007.
• Δ40 = Gas boilers after 2005 / Oil boilers after 2007.
• Δ30 = Low temperature systems e.g heat pumps.

Watts & BTUs (British Thermal Units) Explained

What is a Watt?

Watts are our main unit of energy/power in the UK, commonly associated with lightbulbs and Home Energy performance certificates (EPCs).

What is a BTU?

BTUs are the unit of measurement used to portray a radiators heat output and a rooms heating requirement. 1 Watt is equal to 3.41 BTUs.

Why are they important?

We buy radiators to heat our homes, right? So, we need a way of knowing if a radiator is powerful enough to heat the room that we are shopping for - Watts and BTUs provide us with a value that makes its easier to compare radiators and ultimately choose the right one for our heating requirement.

Need help figuring out how much heat your room needs?

Our fast and easy-to-use BTU calculator can help you:

• Work out a heating requirement value (in BTUs & Watts) for your room
• Show you in-stock radiator recommendations that can fulfil this heat requirement