Is a bypass humidifier a bad idea for a condensing gas furnace?

Users who are viewing this thread

afhoke

New Member
Messages
2
Reaction score
0
Points
1
Location
Colorado
I have a two-stage condensing gas furnace (Payne PG9MAB I think), and I would like to install a bypass evaporative humidifier (AprilAire 400). But, given that the furnace achieves its high efficiency by condensing most of the moisture out of the air, isn't the furnace going to defeat the purpose of the humidifier?

In other words, when the furnace is blowing, some of the warm air will go through the bypass humidifier and pick up moisture. But before the moist air can get to the living space it will have to go back through the furnace, which will suck the moisture back out, right? I hope I'm wrong...
 

Reach4

Well-Known Member
Messages
38,795
Reaction score
4,413
Points
113
Location
IL
The condensing furnace is condensing the moisture in the fire side of the heat exchanger. The humidifier is only affecting the indoor-air side of the heat exchanger. Don't worry about about the humidifier moisture getting sucked back out by the furnace.
 

LLigetfa

DIYer, not in the trades
Messages
7,497
Reaction score
575
Points
113
Location
NW Ontario, Canada
If you feel a need to add moisture to the air, then you should explore how to stop the moisture from leaving in the first place. Chances are that if you have a leaky building envelope, that the moisture is condensing on the cold side of insulation and rotting the building.

A modern, well sealed building does not need moisture to be added but rather needs moisture to be removed.
 
Last edited:

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,771
Reaction score
1,191
Points
113
Location
New England
SHort answer...it will work and not cause issues with the furnace. Whether you need one is another issue altogether. The leakier the house, the more likely you need one. FWIW, some air infiltration is good, but it is best done in a controlled manner; otherwise, the house air can get quite stale.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks