What is one Zone per Floor? 

 A one zone per floor model is one where the entire floor plate makes up a single thermal zone.

Where Sefaira uses one zone per floor

• Plugin - Default setting
• Web Application - Optional setting

How results will be affected

The main way results will be affected is through the averaging of loads across the one zone. For example, let’s assume it’s a cold, sunny day and our building has pretty high occupant and equipment loads. A one zone per floor analysis will average out the gains from people, equipment and sun on one side of the building, with losses out the glass and due to infiltration around all sides of the building.

This means that the one zone per floor model will probably underestimate both the heating and cooling needed by the building.

Generally speaking for buildings with decent internal loads, the predominant impact of simplifying down to one zone per floor zoning should be to see the heating energy being underestimated.

What are the benefits of using one zone per floor? 

Sefaira uses a one zone per floor approach to all models run in the plug-ins because it is a reliable way to provide the user with results that can be used to comparatively assess the energy impact of different facade strategies at the conceptual stage.

If you are comparing forms, window to wall ratios and shading or space plan, a one zone per floor will usually provide good guidance in the relative merits of design strategies.