Hot and humid basement - What to do?

[phucheneh]

Okay, why are more people not baffled by statements of 'my insulated basement is too hot, and when I purposefully humidify it, it gets too humid'?

Uh...don't...use...a humidifier?

 

[Imp]

I did some reading on A/Cs over the weekend for a different matter... Apparently, they do dehumidify to some degree, but that's not their focus, and cheaper units don't even control humidity (i.e. it doesn't cool until humidity is __%). Whatever humidity they remove is just a byproduct of having moist air pass through the cooling coils that are below the dew point temperature. To lower humidity further, it may be necessary to lower the target temperature. Hence, they don't necessarily lower humidity to a "comfortable" range. And double-hence, some people install both a dehumidifier and A/C.

That's all out of my ass, so do your own research.

 

[vi edit]

Okay, why are more people not baffled by statements of 'my insulated basement is too hot, and when I purposefully humidify it, it gets too humid'? Uh...don't...use...a humidifier?

I think he forgot to put a "de" in front of that. He isn't humidifying it.

Just like I missed the "heat pump" part of his water heater. He's already doing what I suggested.

 

[TwiceOver]

Why did you insulate the basement? That's a big mistake.

If you didn't do that, your basement would've maintained a perfect temperature all year round (ok fine, you would need some heat).

In MOST of the cases, insulating basement walls = no no

This. Take the insulation out and it'll probably be all good.

 

[phucheneh]

I think he forgot to put a "de" in front of that. He isn't humidifying it.

Just like I missed the "heat pump" part of his water heater. He's already doing what I suggested.

Okay...makes a little more sense now, then. I just figured ATOT was anal enough to take stuff literally and not quietly assume he meant otherwise.

And AC dehumidifies very, very well. There's a reason your home and car AC both have dedicated drain pipes. More or less, an AC unit basically is one of the most effective types of dehumidifers, but without the waste of trying to warm the air back up. I.e. a dehumidifier is not an AC unit without the cooling part....it's the whole thing. Plus a heater.

 

[bignateyk]

I installed an Energy Recovery Ventilation System that blows fresh air into my basement, along with a ductless heat pump in the basement (one of the four zones). I run that as well as a dehumidifier. Dehumidifier would still be needed even if you have an AC because the AC will end up making it 50 degrees in there before it removed the same amount of moisture as the dehumidifier.

 

[Imp]

I installed an Energy Recovery Ventilation System that blows fresh air into my basement, along with a ductless heat pump in the basement (one of the four zones). I run that as well as a dehumidifier. Dehumidifier would still be needed even if you have an AC because the AC will end up making it 50 degrees in there before it removed the same amount of moisture as the dehumidifier.

Ya, that's what I was tripped up on and why I did some research. I learned about the basic math of HVACs in school and remembered that a heater was always needed after a major dehumidification process. That was probably "precise" temperature control, whereas central A/C appears to just focus on lowering the temperature, then dumping it back in the house and hoping for the best.

 

[Sho'Nuff]

Do you have electric water heating, and is it in the basement? If so you could look into those hybrid water heaters that effectively are heat pumps.

The suck up the heat in the surrounding area, condition it, and then use that to help heat up the water in addition to electric elements in the tank. They'll lower the ambient temp, condition the air, and reduce your electric bill for your water heating needs.

That is exactly what I am having installed. The unit that is going in is the Stiebel Eltron Accellera 300. Best HHWH on the market currently. I called their customer support earlier and they said that while the unit will dehumidify the surrounding air to some extent, it should not be relied on for constant dehumidification as it will only dehumidify when the unit is running (maybe for an hour each day).

 

[Sho'Nuff]

I'm not sure if a ducted humidifier would increase the humidity that much better than a plain ol' humidifier would.

Derp. Typo. Meant to say ducted dehumidifier.

 

[Sho'Nuff]

Okay, why are more people not baffled by statements of 'my insulated basement is too hot, and when I purposefully humidify it, it gets too humid'?

Uh...don't...use...a humidifier?

Sorry for the typos in the OP. I posted it quickly and didn't proofread.

To clarify - basement is humid. I am using a dehumidifier to lower the humidity. The dehumidification process converts latent heat in water to sensible heat, which warms the supply (dried) air. Over time, this increases the temps in my basement by 10+ degrees.

FWIW, I decided today to purchase a Santa Fe Classic whole house dehumidifier. I'm going to put put it in my utility room with my new hybrid HWH and hope for the best. My understanding is that the whole house unit should run circles around my existing dehumidifier. Most reviews I've read say that once installed a whole house unit will run for a few days straight to dry an entire basement out, and then run intermittently after that point. Going to try to simply site the unit in my utility room without ducts and see what happens. There is a louvered door separating that room from the finished area and air can flow through gap between the drop ceiling in the finished space and the floor joists in the unfinished space, so I shouldn't create a negative or positive pressure space.

 

[Sho'Nuff]

Update: So I figured out what was causing my basement to get so hot. During the remodeling process, the contractor walled in the flexible ducting from our dryer. That ducting extends from our dryer down through the first floor and into our basement, where it is hung from basement ceiling behind a wall until it exits the house. After noticing that my basement smelled like dryer sheets one day, I opened an access panel to discover that the dryer vent had ripped. As a result, all the hot exhaust from the dryer was being discharged behind one of my newly finished walls. I replaced the ducting and voila! Cool basement. 70 degrees all the time down there now. Still have a humidity issue, but I fixed that with the whole house dehumidifier mentioned in my previous post.

BTW - my new hot water heater (Stiebel Eltron) is AWESOME! No oil usage and my electric bill only went up by$18 bucks.

 

[Dirigible]

Hooray! Cheap fix!

 

[Codewiz]

Update: So I figured out what was causing my basement to get so hot. During the remodeling process, the contractor walled in the flexible ducting from our dryer. That ducting extends from our dryer down through the first floor and into our basement, where it is hung from basement ceiling behind a wall until it exits the house. After noticing that my basement smelled like dryer sheets one day, I opened an access panel to discover that the dryer vent had ripped. As a result, all the hot exhaust from the dryer was being discharged behind one of my newly finished walls. I replaced the ducting and voila! Cool basement. 70 degrees all the time down there now. Still have a humidity issue, but I fixed that with the whole house dehumidifier mentioned in my previous post.

BTW - my new hot water heater (Stiebel Eltron) is AWESOME! No oil usage and my electric bill only went up by$18 bucks.

How much did it cost to install the Stiebel Eltron? For my house, I would need three 60amp breakers. The cost of the instant heaters like that have come down in price.

 

[dfuze]

Ha, that's how I found the tear in my dryer vent about 2 years ago too... basement started to smell too mountain fresh. The dehumidier is awesome, keeps the basement a cool fun place to escape the summer heat!

 

[Imp]

Well, that saved a ton of trouble...

 

[Sho'Nuff]

How much did it cost to install the Stiebel Eltron? For my house, I would need three 60amp breakers. The cost of the instant heaters like that have come down in price.

The Stiebel was $3300 installed. $2400 for the unit, ~$100 for a condensate pump, ~$600 for plumbing, and ~$200 for electrical (needed a 240V outlet and 2 30A breakers installed). I figure that I'll see a ROI in a little over five years, as it will cost me ~$600 less a year to run than using my oil furnace. It also provides enough capacity for us to use our jacuzzi tub (something we couldn't do before), cools and dehumidifies my basement (when running), and is (much) quieter than my oil furnace. It also means that we will likely never run our furnace again, as between it and our pellet stove we should be almost 100% oil free.

FWIW, the Steibel is designed to run off the heat pump 99.9% of the time. The only time the backup electric element runs is during periods of very high demand, when the hot water level drops below 25% of the tank. And even in that case, the element only heats 1/3 of the water. Pretty much a non-issue in my family, as my wife and I take short showers and our young kids take baths in ~3-4" of water.

 

[bignateyk]

I put a minisplit in mine. It functions as both AC and dehumidifier. I also run a regular dehumidifier because otherwise the minisplit cools it down too much in order to dehumidify it.

 

[Juddog]

Update: So I figured out what was causing my basement to get so hot. During the remodeling process, the contractor walled in the flexible ducting from our dryer. That ducting extends from our dryer down through the first floor and into our basement, where it is hung from basement ceiling behind a wall until it exits the house. After noticing that my basement smelled like dryer sheets one day, I opened an access panel to discover that the dryer vent had ripped. As a result, all the hot exhaust from the dryer was being discharged behind one of my newly finished walls. I replaced the ducting and voila! Cool basement. 70 degrees all the time down there now. Still have a humidity issue, but I fixed that with the whole house dehumidifier mentioned in my previous post.

BTW - my new hot water heater (Stiebel Eltron) is AWESOME! No oil usage and my electric bill only went up by$18 bucks.

Ahh good find! I had the same thing happen to me one time; the dryer vent was dislodged, and when I went down to the basement, it was super hot and humid. I taped it up with that weird shiny tape that looks like aluminum foil, because air was coming out through little tiny cracks in the vent.