Chimney's Size vs. Boiler Power

The size of chimney vs. boiler's heat load. Reference table showing required chimney cross-sectional area based on boiler heat capacity.

Boiler Capacity (kW)	Boiler Capacity (Btu/h)	Required Chimney Area (cm²)	Required Chimney Area (in²)
15	51000	115	18
23	78000	150	23
35	119000	200	31
46	157000	250	39
58	198000	300	47
70	239000	350	54
81	276000	400	62
93	317000	450	70
104	355000	500	78
116	396000	550	85

Conversion Factor

1 kW = 3412 Btu/h

Important Note

⚠️ Always check local authorities before final design.

Usage

Select the boiler capacity closest to your requirements and reference the corresponding required chimney area in both metric (cm²) and imperial (in²) units.

Chimney's Size vs. Boiler Power | MEPKit Engineering Tools | MEPKit