What Thread Does Your Heater Have?

If you don’t know what thread your heater has, we’ve provided some information about the most common threads below.

In the case of less common threads, we require a model of the original heater.

Heating sets in plugs usually have a thread size of 1 1/4 inch (or 5/4) or 1 1/2 inch (also known as 6/4 or 3/2).

If the diameter of the thread of the heater is:

Approximately 4.2 cm (41.910 mm) - it’s a 1 1/4 inch thread.
- A 1 1/4 inch thread hole where the heater is countersunk has an inner diameter of 3.9 cm (38.952 mm).
Approximately 4.8 cm (47.803 mm) - it’s a 1 1/2 inch thread.

Heaters for bathroom radiators usually have a thread size of 1/2 inch, which means:

Approximately 2.1 cm (20.955 mm) - it’s a 1/2 inch thread.
- A 1/2 inch thread hole where the heater is countersunk has an inner diameter of 1.9 cm (18.631 mm).

Single heating elements typically have bushings with threads of M10x1 or M14x1.5:

The above metric threads may have different attributes. The suggestions provided are for the most common heaters.

Common Thread Sizes

Size of the Thread	External Thread (Heater, Screw) [mm]	Internal Thread (Hole, Nut) [mm]
1/2”	20.955	18.631
3/4”	26.441	24.117
1”	33.249	30.291
1 1/4”	41.910	38.952
1 1/2”	47.803	44.845
2”	59.614	56.656
2 1/2”	75.184	72.226
M10x1	10	8.773
M10x1.25	10	8.466
M12x1.25	12	10.460
M14x1.5	14	12.160
M16x1.5	16	14.160
M48x2	48	45.546

For each part, we provide a 12-month warranty.