Are whole-home dehumidifiers or portable dehumidifiers better value?
I need to plan for supplemental dehumidification for my whole house (~1600sq ft, 2 story slab on grade duplex, zone 4a) and am trying to decide what kind of dehumidifier to buy and where to put it.
Option 1: buy a typical portable dehumidifier for like $300
Option 2: buy a ducted, whole-home dehumidifier like Santa fe or aprilaire e80, which are like $1500
I’m sure the santa fe and aprilaire units are better built & last longer, but the efficiency boost only looks marginal (ENERGY STAR Certified Dehumidifiers | EPA ENERGY STAR) (they’re all between 2 and 2.35 l/kwh). Will they really last 5x as long? Are there other ductable units that are better options?
The biggest problem with the portable units is where would I put it? Autodrain is crucial for me. And I don’t see a great option out in the open somewhere. I have a small mechanical closet on the first floor it could go in conveniently and autodrain (and it would dampen noise a bit), but I worry it wouldn’t dehumidify the rest of the house very well. Is there a way I could ventilate that closet sufficiently to make it work?
Thanks for any input!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
If you're only trying to deal with some excess humidity in a basement or accessible crawlspace, a portable unit is probably fine. If you are trying to control your indoor humidity levels during seasonal transitions or in a humid area, then the whole home unit is a better way to go. I'd be more concerned with the application here than I would the efficiency. Portable units are not the best option when you have large amounts of humidity to deal with over extended periods of time.
Portable units are more likely to fail if you run them a lot. The permanently installed units tend to be more robust.
Bill
Thanks. I've been trying to gauge how much dehumidification I'll need, but with the home under construction, lack of insulation, and attic partially open, it's hard to tell. I'm definitely looking for "controlling humidity during seasonal transitions in a humid area" though, so your point about portable units breaking down if run a lot is helpful.
Any advice on how you would duct it? Would simply finding a way of pulling from upstairs and blowing out downstairs work? Or is ensuring distribution by integrating with hvac supply ducts worthwhile?
You won't be able to gauge things until you're dried in and air sealed. In my own home, a lot of the humidity comes in from the to-be encapsulated crawlspace, which I have partially done but never seem to have the time to completely finish! I have two of those, one is done, the other I have the materials but need to install everything.
Air leaks are going to bring in moisture if you're in a humid environment. Your dehumidifier will constantly be fighting how ever much leaks in through those air leaks. That's what will ultimately decide how much dehumidification you need. Homes that are very well air sealed will do better than more leaky homes.
I have a protable unit running right now. It's my third one. The first came with the house, an old GE unit, and it ran for years. The second was something from the blue store, and it ran another 3-4 years or so then started flashing an error code and running intermittently. The new unit is something from the green store. So far it's going strong, but it's not even 1 year old yet. It runs very nearly continuously through the summer, cycles maybe to 50% or so in the winter.
The usual whole-home dehumidifiers are installed with the HVAC system, and use the same ducts. I know that at least some of the Aprilaire units can operate standalone, and could be ducted seperately from the rest of the system. If I were to install one that way, I'd draw from the upper level and exhaust to the lower level. Moist air rises, so ducting things this way would make stratification work for you.
Bill