Multifamily Humidity Control Problems: Muggy Mayhem

Multifamily buildings with good insulation, great windows, and decent ventilation systems – what's not to like? Unfortunately, over the past five years, we have received calls from multifamily building owners who are battling persistent summertime humidity problems. Comfort complaints, sweating ductwork, waterlogged drywall, and mold on furnishings, clothing, registers . . . you name it. We will discuss how we went about these investigations and the tools we used to diagnose these issues. When investigating these problems, unfortunately, there was no ‘magic bullet’ or single cause that we could pin down: it was often a perfect storm of factors. From air conditioner sizing vs. cooling load, to poorly configured cooling systems, to outside air ventilation system problems, to catastrophic air leaks - we will look at them all, and discuss how to identify and fix these issues.

Session Speaker(s): 

Session Chair(s): 

Event Time: 

Thursday, May 6, 2021 - 3:30pm to 4:30pm

CEU Information: 

AIA 1.0 LU/HSW
BPI 1.0 hour
GBCI LEED BD+C, ID+C, O+M, WELL 1.0 hour
Conference-day attendance credits available from PHIUS, RESNET, and Mass. CSL

Learning Objectives:

  • Identify the factors that contribute to humidity control issues in multifamily buildings
  • Describe the importance of the cooling temperature difference or ‘split’ across the unit for humidity control
  • Describe how variations in outdoor dewpoint affect interior humidity and comfort levels, due to air leakage and ventilation
  • Recognize how changing cooling loads are affecting cooling equipment sizing and runtimes

Session ID: 

BOS21-617