Evoke Air Tightness Calculator Launch

If converting between modelled infiltration rates and air tightness testing targets is only simple math, then why is it so annoying? IFYKYK. Here’s our shortlist of reasons:

• Some codes specify modelled infiltration rates (ex. NECB), while others specify air tightness testing targets (Ex. ASHRAE 90.1) at various pressures (ex. 50 Pa or 75 Pa)

• Some codes say the infiltration rate should be applied only to above-ground wall area (Ex. City of Vancouver Energy Modelling Guidelines), and others also include roof areas (ex. NECB)

• Different codes have different infiltration rates (ex. 0.20 vs. 0.25 L/s/m²) and/or air tightness testing targets (1.50 vs. 2.03 L/s/m²)

Usually, infiltration/air leakage has a significant effect on both heating/TEDI and energy use/TEUI. Incorrectly modelling infiltration rate can accidentally omit sensible design options or lead to false compliance. Additionally, claiming infiltration savings can tip an energy model into compliance, however, the corresponding air tightness target may not be practically possible!

Evoke has built an air tightness calculator to convert between modelled infiltration rates and air tightness testing targets for several codes and standards. Rather than scrolling through codes to check the same numbers and menial details over-and-over, we’ve put them all in one place. Enjoy.

https://www.evokebuildings.com/airtightnesscalculator

- M’Beth Schoenfeld