In this tutorial we're going to cover how roofs are defined in the Zebra model.

The roofs tab is one of the simpler input sheets, and it just allows us to define an area and U-value for up to three roof elements. In reality a lot of the time we would only have one.

Once we define roof elements the spreadsheet will calculate and summarize the space heating demand, and the space cooling demand. Both will be broken down by the roof element we've defined. and also by the months of the year.

The areas and U-value we use depend on the context; these are the areas and U-value through which energy will be lost. So for instance in a unheated attic space this would be the area of the ceiling and the U-value of the ceiling, whereas if an attic space were heated and occupied this would be the area instead of the pitched roof and the U-value of the pitched roof material.

Like for the other building fabric input sheets, if we change the complexity level it doesn't actually increase the number of inputs we have to define, but it does instead show more detail on the calculations that have been performed.