The “House with 80% Relative Humidity Inside”
“A lot can change in a house in 15 years.”
— Home Energy Solutions
HVAC Contractor was hired to replace an aged furnace, A/C and duct system
For their new equipment the HVAC company simply used the sizing of the previous equipment without verifying if any of the building's faculties had changed since the original equipment was installed more than 15 years ago.
Turns out, a lot had changed. Over 15 years this home:
had new attic insulation added
additional air sealing had been performed
a 350 sf patio had been remodeled
new bathroom installed
and all of these improvements were within the conditioned space of the building
We determined there was a great deal of connectivity between the crawlspace and the conditioned area above. We found holes in the combustion closet (where the furnace is located) that were created to provide make-up air for piping to the sealed combustion furnace. Air from your crawlspace is not the air you want circulating in your home. Our report outlined the corrective actions that were needed and left the homeowner with the information they needed to make a proper decision for remediation.
Homeowner’s Habits Had a Big Impact on Humidity
After speaking with the homeowner, we learned he liked the outdoors, so much in fact they would open all the windows in the house during the summertime in order to appreciate a nice cross breeze through the house.
Unfortunately, a lot of moisture vapor was coming inside along with the ambient air. The AC equipment and its dehumidifier (coil) would be off in the evenings until the next day when the ambient (outside) temperatures caused the AC equipment to come on. By that time, a lot of excess moisture had built up in the home and many cooling cycles were required to bring the humidity back down to comfortable levels.
Home Energy Solutions was able to:
educate the homeowner on where the extra humidity was coming from
save the HVAC contractor the hassle of installing equipment that didn’t need replacing
confirm the proper sizing of the equipment needed
The HVAC Contractor was very pleased to know they were not at fault and that replacement equipment did not have to be installed.
In this case, the HVAC contractor didn’t waste time trying to chase down a ghost when they could be making money on another job. Some contractors have a knee-jerk solution by pulling out the AC coil and replacing it with a model that would have provided a steeper dehumidification profile. Had this contractor done that, and simply made a move to change out equipment, they would have soon found out that the issue would not be corrected and would have realized that their efforts were in vain.
