German Heater Sizing Guide: Accurate Heating Solutions for Your Home

How to Choose the Right Heater Size

Selecting the correct heater size ensures your room heats up efficiently, your bills stay low and your unit enjoys a long life.

Calculate heat requirement: see how to do it below the table of heater sizes
Always round up: pick the next standard heater size—never round down—to allow the thermostat to cycle off.
Leverage stored heat: once the element switches off, the clay core continues to radiate warmth.

By matching your room’s heat requirement to the right model, your heater will reach the set temperature, switch off, and maintain comfort from stored thermal energy. In. Details on how to do this are below the table

Standard Model Height 600 mm

Model	Height	Length	Depth	Weight (kg)	Weight (lbs)	Power
S500	600	350	80	17	38	500
S750	600	350	80	17	38	750
S100	600	650	80	32	71	1000
S150	600	650	80	32	71	1500
S151	600	950	80	46	102	1500
S200	600	950	80	46	102	2000
S201	600	1250	80	58	128	2000
S202	600	1550	80	75	166	2000
S250	600	1250	80	58	128	2500
S251	600	1550	80	75	166	2500

Low Level model Height 380 mm

N50	380	650	80	18	40	500
N100	380	650	80	18	40	1000
N101	380	950	80	27	60	1000
N150	380	950	80	27	60	1500
N151	380	1250	80	36	80	1500
N200	380	1250	80	36	80	2000
N201	380	1550	80	45	100	2000
N250	380	1550	80	45	100	2500

Vertical Height 1200 mm

H100	1200	350	80	34	76	1000
H150	1200	650	80	64	142	1500
H200	1200	650	80	64	142	2000

Compact Height 220 mm

T1000	220	650	130	19	42	1000
T1500	220	950	130	28	62	1500
T2000	220	1250	130	37	82	2000
T2500	220	1550	130	46	102	2500

Determining Your Room’s Volume and Heater Power required

Before selecting a heater, calculate your room’s volume (length × width × height) . Always round up to ensure efficient cycling.

Use the table next to this text to match the heater power (in watts) with the maximum volume (in m³) it can heat.

Power requirement is based on the volume of the room that is being heated and the heat loss dependent on insulation. We have assumed a fairly average heat loss factor to enable you to work out what power of heater you need for your room. Conservatories require more heat per cubic metre due to more heat loss through the glass. If in doubt, please feel free to get in touch and ask.

Power (W)	Max Volume (m³)
2500	58
2000	47
1500	35
1000	23
750	17
500	11

modern German storage heaters