Hi All,
I'm an Architect who focuses on parametric design. I've been taking a lot of time learning the ins and outs of Energy Plus via Grasshopper/Honeybee. So far I feel like I have a good handle on things, but one thing is always sticking out as a problem for reliable EUI calcs.
How do y'all manage infiltration in your models? From my understanding, the infiltration really depends on the detailing and the skills of the contractor. In Washington State, the energy code requires a certain ACH target, which is fine, but the difference between, say 2 ACH/50pa and 3 ACH/50pa is like 10 to 20 EUI points in some models. I always find that tweaking the thermal performance of the building moves the EUI a few points up and down, but even small tweaks to the infiltration rate has a huge effect.
I am pushing for more blower door tests just to understand how our detailing and contractors work when it comes to infiltration, but we don't always have that option.
For what it is worth, this is only relevant as we are participating in the AIA DDX 2030 challenge and I'd like to feel good about the projected EUI's we are posting.
So how do you determine your infiltration rate in EnergyPlus? Is it with a baseline, with a code/certification target, or with historical data from past projects?
