Whole house - forced air dehumidifiers

[revelations]

It may sounds strange in Calgary that this would be brought up, but we just purchased a really nice older house in an older location.

Unfortunately, back in 1979, basement floors weren't sealed with plastic underlay before the concrete was laid down - which leads into a damp/humid/musty basement (60-70% RH) in the summer/fall months. Even up on the second floor its 50-60% which makes for semi-uncomfortable hot summer days. We expect this to be a problem 6 months of the year (from ground thaw to ground freeze)

We have a dual furnace, forced air system and presumably I would add the dehumidifier to the lower-level system - anyone have any suggestions for a good unit? Lennox?

The basement is HUGE so a portable unit isnt really appealing.

[ExtraSlow]

Are the zones split upper/lower? Do you run the recirculation fan all the time? You are right that this is an unusual problem in this climate.

[Darell_n]

I would probably look at having the basement sealed up rather than chasing the symptoms of the problem. Who know what other nasty issues might arise.

[Darell_n]

Also, another name for whole house dehumidifier is central A/C.

[revelations]

^ yea we looked at a Central A/C but with a 2100sqft house we guessed around 4-5000$ for everything.

A central dehumidifier is something I could do myself and probably get it done for 1000$.... unless my numbers are completely wrong

The basement is fully developed, ripping up the walls and the floor to seal them would mean a lot of $$.

No, we dont run the air systems in the summer but I would like to start doing this.

System is split to Basement/Main and Upstairs zones.

[ExtraSlow]

If you have moisture problem in this climate, running the recirculation fan 100% of the time will probably be all you need. This is practically a desert.
If there is a corner of yoru basement that doesn't get good airflow, get a portable fan set up in that area. Maybe put it on a timer so it runs when you aren't there.

Since you say you don't have AC, I assume you have your windows open pretty often too?
Maybe you can get some passive airflow by opening some windows in the basement and some on the top floor to get a bit of a "stack effect" going?

I honestly think if your airflow is poor, a dehumidifier isn't going to "reach" those problem areas anyway. Focus on airflow first, and you'll probably find mechanical dehumidification isn't required.

Do these things for a week, and I'd be shocked if your humidity levels haven't dropped significantly.

[ExtraSlow]

Also, if you have been doing this for a while. Please post up your humidity readings.

[revelations]

^ Thanks for the tips - I've been running a portable dehumidifier and its pulled out about 15L of water in 48 hours. Humidity is down to 50-55% now. I have fans in the basement as well.

I also found out that the basement bathroom ceiling vent fan was sealed shut by the nubtards that sprayed the ceiling plaster (all over the fan/vent mechanism) - opening up the vent hole now actually allows the air to flow freely outside after having a shower.

I'm looking at changing out the controls for the forced air flow system - I would like for it to automatically run during the day to move air around the house in the summer.

[benyl]

You should be running your furnace fan 24/7.

Have you checked for mold?

[ExtraSlow]

Agree, run the furnace fan 24/7, the only reason I was suggesting a timer on the portable fans was that it might be loud or breezy while you were using that space. 24/7 would be ideal. particularly when you are trying to dry the room out.

[revelations]

I've pulled the basement baseboard out in some locations (eg bathroom) and behind the baseboard there are some indications of mildew/mold on the drywall. Nothing rotting or anything though (unlike what we're dealing with in the master bathroom shower during the reno). Ill probably end up pulling all the baseboard out at some point.


Why would the fans need to run 24/7, 6 months of the year? A few hours a day should be more than adequate. We leave our windows open in the basement as well (except when its raining).

[ExtraSlow]

run then 24/7 until humidity levels in the basement are same as outside your home. Then optimize.

[revelations]

Will do, thx for all the help folks!

[ExtraSlow]

No problem man. And if you do ever decide to do whole house AC, there is a beyond hookup for that too, just search. Just get a handle on your humidity first.

[benyl]

My furnace fans run 24/7 365.

It balances the temp and humidity in the whole house.

[ExtraSlow]

I run the fans 24/7 in the summer to help the AC balance temps. in winter it doesn't seem necessary.