Radiator Sizing Guide
Radiator selection depends on both room heat load and the actual water-to-room temperature difference.
What matters most
Nominal radiator output is tested at a reference temperature difference. When supply and return water temperatures change, the actual output per section also changes.
Common mistakes
- Using high-temperature catalog output for low-temperature heating systems.
- Forgetting to round section counts up to whole sections.
- Comparing panel and column radiators without checking manufacturer output data.
When to use the calculator
Use it after you know the room heating load and want an early estimate of radiator sections or area.