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FCU Size Calculator
Calculate the required Fan Coil Unit (FCU) capacity for any room. Enter the floor area, heat/cool load per square metre, and ceiling height.
How to Size a Fan Coil Unit
FCU capacity is determined by the room's heating or cooling load. The load is calculated as: Load (W) = Area (m²) × Load (W/m²). Typical office loads are 80–150 W/m².
Always select an FCU with a capacity slightly higher than the calculated load (10–15% margin) and check the manufacturer's performance tables at the design water temperatures and air temperatures.
Frequently Asked Questions
What is a Fan Coil Unit?
An FCU is a device that heats or cools air using hot or chilled water coils. It's used in commercial buildings with central plant (boilers and chillers) supplying water to multiple FCUs.
What water temperatures do FCUs use?
Hot water: typically 80°C flow / 70°C return. Chilled water: 6°C flow / 12°C return. Low-temperature FCUs may use 45°C/35°C hot water.
FCU Size Calculator
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