Many design studies look to undertake a comparative workflow comparing different options alongside one another. 

In many cases, these comparative design studies tell the story using a stacked bar chart showing the energy breakdown of each option.

The stacked bar is useful for many reasons:

• You can compare the total energy usage and show progressive reductions in usage with the total height of each bar
• The stacked energy use breakdown can show for different options where the highest remaining portions of energy use are, so that you can target those elements of demand first in working out how to reduce energy next.

How to create a stacked-bar chart in Sefaira

You can easily create a stacked bar chart in Sefaira comparing all of the iterations (also known as clones) that you have created in your model.

Go to the energy tab and click the "Show Comparison" tick box in the top right corner of the pie chart card:

The view will switch to a series of stacked bars

The active iteration that you have selected is in bold (ASHRAE Baseline) in the example above.

You can toggle between Energy, Cost and CO2 by clicking the toggle buttons. The example below includes a toggle for CO2e.

The drill-down feature

Click on any of the bars to see a more detailed view of any of the categories of energy use. In the example below, cooling has been selected:

Any category of use can be drilled down to. 

Example

We're doing an HVAC Options study, looking at 3 different HVAC system approaches:

• VAV with Rooftop Package Unit
• VAV with Central Plant
• Passive Chilled Beams

After setting up the 3 options using the clone feature, we click the compare feature to get a graph that can be readily output to compare the 3 design alternatives.

The graph makes it clear which solution has the lowest energy (Passive Chilled Beams) and where the energy has been saved (mostly in heating and cooling).