When modeling slab-on-grade floors in energy simulation software like eQUEST, EnergyPlus, or TRACE 700, you've probably seen references to something called the F-Factor. But what exactly is it?

The F-Factor is a simplified way of describing the heat loss rate through a slab-on-grade floor based on its perimeter length, not its area. It’s defined in units of Btu/hr·ft·℉ and allows modelers to account for ground heat transfer without needing to get into complex soil thermodynamics. That’s why it's so useful — and why it's required by ASHRAE 90.1 for certain modeling paths.

ASHRAE 90.1...

Plug loads—everything from computers and copiers to coffee makers and vending machines—can represent a surprisingly large slice of a building’s energy pie. When you don’t have detailed equipment schedules or measured data, industry-standard references can help you make reasonable assumptions typically accepted by rating authorities.

It’s important to get your plug loads as accurate as possible. Apart from being a major source of energy consumption, plug loads influence equipment sizing, airflow, and psychrometrics. More than that, if plug loads are equal between your proposed and baseline model (think LEED), oversized plug loads...

About two months ago, I created an AI energy model to determine how much time and effort it required. Much to my surprise, it was faster and easier than I expected, with some interesting challenges, and I will outline the process here. Note that this process works with any software. I chose eQUEST because it required me to gather data from varying text-based files. After all, most AI requires collecting and organizing data that isn't in Excel format.

Here's a quick rundown of how it worked: