Bedroom dehumidifier advice
June 6, 2021 12:36 PM Subscribe
My bedroom is partly a garage conversion (so, cement under the laminate floor, I think, but seemingly well insulated walls) and stays fairly cool even when it's hot outside--it's currently 93 degrees out at 3:30pm but only 73 in my room. However, it gets pretty humid--currently 75% but the other day it was 88%.
This is mostly tolerable in this temperature range, but seems to lead to condensation. My (laminate) floor was slightly damp/wet the other day, enough to be unpleasant, and clothing/sheets end up feeling slightly damp too. I'm new to this house, housemates in the rest of the house also don't need AC as long as they keep windows open at night when it's cool and then close windows + shades in the morning. It gets slightly warmer in their part of the house but they don't seem to deal with this level of condensation--presumably because I have a cement floor and they don't.
Is a small dehumidifier the best strategy? Can you recommend specific models/brands that are reasonably priced?
A window AC is also possible (and I own a window unit that's OK but probably 15+ years old, in storage) but I don't really want to use that much electricity if I don't specifically want/need to feel cooler, plus I don't want this level of dampness in my room when I'm not home, either.
This is mostly tolerable in this temperature range, but seems to lead to condensation. My (laminate) floor was slightly damp/wet the other day, enough to be unpleasant, and clothing/sheets end up feeling slightly damp too. I'm new to this house, housemates in the rest of the house also don't need AC as long as they keep windows open at night when it's cool and then close windows + shades in the morning. It gets slightly warmer in their part of the house but they don't seem to deal with this level of condensation--presumably because I have a cement floor and they don't.
Is a small dehumidifier the best strategy? Can you recommend specific models/brands that are reasonably priced?
A window AC is also possible (and I own a window unit that's OK but probably 15+ years old, in storage) but I don't really want to use that much electricity if I don't specifically want/need to feel cooler, plus I don't want this level of dampness in my room when I'm not home, either.
A dehumidifier that is vented to the outside is called an air conditioner.
A dehumidifier is essentially an air conditioner that is not vented to the outside. All the electric energy stays in the room as heat. It's hard to say if you would feel better. More heat vs low humidity. You'd probably feel hot and dry.
Since you would be paying for electricity either way, you would probably be better with the air conditioner (cool and dry).
If it's still wet you could get the dehumidifier and have them fight each other/s.
posted by H21 at 2:36 PM on June 6, 2021 [3 favorites]
A dehumidifier is essentially an air conditioner that is not vented to the outside. All the electric energy stays in the room as heat. It's hard to say if you would feel better. More heat vs low humidity. You'd probably feel hot and dry.
Since you would be paying for electricity either way, you would probably be better with the air conditioner (cool and dry).
If it's still wet you could get the dehumidifier and have them fight each other/s.
posted by H21 at 2:36 PM on June 6, 2021 [3 favorites]
Response by poster: I’m pretty comfortable with the air as it is, I just don’t want the level of condensation that’s happening.
Does an air conditioner not use more electricity than a dehumidifier?
posted by needs more cowbell at 3:51 PM on June 6, 2021
Does an air conditioner not use more electricity than a dehumidifier?
posted by needs more cowbell at 3:51 PM on June 6, 2021
These humidity levels are mold growth territory. You need to dehumidify or air condition. Given it is already 73 in the room, it may be tough to balance as the AC can only remove moisture by lowering temperature and a dehumidifier adds all its heat to the room raising temperature. The comment above about one of each and letting the fight it out may have been in jest but it likely isn’t far off.
posted by meinvt at 4:55 PM on June 6, 2021 [2 favorites]
posted by meinvt at 4:55 PM on June 6, 2021 [2 favorites]
Use a regular fan and circulate air into the rest of the house. I would expect the surfaces to be dry to the touch with even a box fan on low.
It's pointless to both open windows and use a dehumidifier or A/C. Either live with the elevated humidity or stay sealed and run the A/C.
posted by flimflam at 10:56 PM on June 6, 2021
It's pointless to both open windows and use a dehumidifier or A/C. Either live with the elevated humidity or stay sealed and run the A/C.
posted by flimflam at 10:56 PM on June 6, 2021
Does an air conditioner not use more electricity than a dehumidifier?
Air conditioners and dehumidifiers both dehumidify air the same way, by blowing it through the cold side of a heat pump. A dehumidifier will generally use less electricity to get the cold side cold enough to do this than an air conditioner would, because heat pumps use more energy the further apart the hot-side and cold-side temperatures are, and dehumidifiers push the air coming off the cold side straight back through the hot side again, making the hot side run cooler than an air conditioner's would for any given cold-side temperature.
Some of the electric energy driving the machine will always be lost as heat, plus the water vapour being condensed out of the air also dumps heat into the cold side as it does so, which means the exhaust air from a dehumidifier will always be a few degrees warmer than the intake air and over time this has to warm the room.
Unless your outdoor overnight air temperature regularly stays uncomfortably high, I'd try using a box fan in the window to exchange stale room air for fresh outside air for an hour or so each night, then closing up and running a dehumidifier for a few hours to dry it out. The dehumidifier's warming effect would probably stay quite tolerable at night and, as you've already found out, the slab's thermal mass will keep the interior temperature pretty stable.
posted by flabdablet at 3:48 AM on June 7, 2021 [1 favorite]
Air conditioners and dehumidifiers both dehumidify air the same way, by blowing it through the cold side of a heat pump. A dehumidifier will generally use less electricity to get the cold side cold enough to do this than an air conditioner would, because heat pumps use more energy the further apart the hot-side and cold-side temperatures are, and dehumidifiers push the air coming off the cold side straight back through the hot side again, making the hot side run cooler than an air conditioner's would for any given cold-side temperature.
Some of the electric energy driving the machine will always be lost as heat, plus the water vapour being condensed out of the air also dumps heat into the cold side as it does so, which means the exhaust air from a dehumidifier will always be a few degrees warmer than the intake air and over time this has to warm the room.
Unless your outdoor overnight air temperature regularly stays uncomfortably high, I'd try using a box fan in the window to exchange stale room air for fresh outside air for an hour or so each night, then closing up and running a dehumidifier for a few hours to dry it out. The dehumidifier's warming effect would probably stay quite tolerable at night and, as you've already found out, the slab's thermal mass will keep the interior temperature pretty stable.
posted by flabdablet at 3:48 AM on June 7, 2021 [1 favorite]
By the way, much of the heat of condensation that a dehumidifier would collect from the water vapour it removes from the air is currently being collected by your floor, which is where quite a lot of that very same water vapour is condensing at present. So if you arrange for the dehumidifier's exhaust stream to be cooled down by blowing along the floor, then not only will your floor stay drier, but the collected heat of condensation will end up in roughly the same place and the only contribution to increased room temperature will be from losses in the dehumidifier mechanism.
You can work out roughly what that's going to feel like for any given dehumidifier operating period by comparing your dehumidifier's rated electrical power consumption to that of a simple fan heater.
posted by flabdablet at 4:03 AM on June 7, 2021
You can work out roughly what that's going to feel like for any given dehumidifier operating period by comparing your dehumidifier's rated electrical power consumption to that of a simple fan heater.
posted by flabdablet at 4:03 AM on June 7, 2021
If the outside humidity is not that high, I'd be curious as to where this moisture is coming from, getting the source of the moisture resolved will be best. I had a long standing dampness problem in my house that I had a bandaid on for years, just running a $100 standalone dehu in the middle of my hall, but turns out water was just flowing in underneath the house anytime it rained so this was a fools errand to get the moisture out of the air.
Make sure whatever one you get emptying the bucket isn't too difficult, or some you can hook up to drain directly into the tub or something. I did have mind overflow occasionally, so either empty it before it auto-shuts off or put it on something that would contain any spills.
posted by theRussian at 6:51 AM on June 7, 2021 [2 favorites]
Make sure whatever one you get emptying the bucket isn't too difficult, or some you can hook up to drain directly into the tub or something. I did have mind overflow occasionally, so either empty it before it auto-shuts off or put it on something that would contain any spills.
posted by theRussian at 6:51 AM on June 7, 2021 [2 favorites]
Agree about venting to outside if you don't want to raise the temperature of the room. I don't know if there are any window air conditioners that do this, but I have a portable air conditioner (that vents through a window) that also has a dehumidify-only option.
posted by Squalor Victoria at 7:42 AM on June 7, 2021 [1 favorite]
posted by Squalor Victoria at 7:42 AM on June 7, 2021 [1 favorite]
I recently bought a dehumidifier. Spent a godawful amount of time researching quiet dehumidifiers. And the one I go is still loud. Kinda like a box fan. *shrugs*
I went with a Midea 22-pint bc it was on sale. Works like a champ. But I turn it off at bed time or trying to watch a movie.
posted by Neekee at 9:40 AM on June 7, 2021 [1 favorite]
I went with a Midea 22-pint bc it was on sale. Works like a champ. But I turn it off at bed time or trying to watch a movie.
posted by Neekee at 9:40 AM on June 7, 2021 [1 favorite]
I'd like to add a slightly off-topic addendum - dehumidifiers appear to be designed to break within 2-4 years of purchase, with a typical mfg warranty of one year. This is the one item that I would strongly suggest you get a 3 or 4-year extended warranty if you plan on using it regularly. I just (like yesterday) went through the claim for the extended warranty from a unit bought in 2018 and the payoff was painless.
posted by Dmenet at 11:26 AM on June 7, 2021 [2 favorites]
posted by Dmenet at 11:26 AM on June 7, 2021 [2 favorites]
In a similar situation, I run the A/C while I'm away at work. It's obnoxiously cold when I get home, but it's tolerable after an hour or two. Opening the window for a short time can fix the temperature without increasing humidity too much (depending on the weather). I had a dehumidifier, but as Dmenet warns, it broke after a few years. It was more effective but very loud.
Make sure you don't leave any fabric items on the floor. I've lost a couple pillows to mold this way, as the temperature difference between the air and the concrete promotes condensation.
posted by Comet Bug at 12:42 AM on June 8, 2021
Make sure you don't leave any fabric items on the floor. I've lost a couple pillows to mold this way, as the temperature difference between the air and the concrete promotes condensation.
posted by Comet Bug at 12:42 AM on June 8, 2021
A dehumidifier that collects water to an internal bucket should always be designed to shut off when the bucket fills. There’s no way they should be “overflowing” water out of the unit. If they are, the fill-level stop switch isn’t working and that’s a flooding hazard.
Many mid to high grade dehumidifiers come with a built in pump to send water up and out of the unit to where you want it to go. Built in pumps are often a weak spot in dehumidifier design, but they are simple and convenient when they work right. Otherwise gravity drain it into a standalone level-triggered pump, which is what I do. That has way more power to send water out anyway.
I own the priciest Frigidaire dehumidifier, highly recommended by the unreliable NYT Wirecutter blog, which I won’t ever trust again. I will NOT recommend it. My first one arrived with the built in pump broken out of the box. It took three months of insane hassle to get it replaced under warranty and I’m not alone in despising Frigidaire/Electrolux customer service.
You get essentially the same Chinese products for 10-20% less buying a Midea or other budget brand unit. Dehumidifiers can last a long time but only if you clean them and maintain them. They are by design a wet and slimy environment and scale and deposits collect in them. I have a heavy duty unit in the basement (what the Frigidaire replaced ONLY because I wanted more energy efficiency) that is approaching 15 years of continuous prior service and works fine, it just draws too much power for my taste. I can already see the newer one likely has about 4-5 years of service to give before cleaning it becomes a futile exercise for me. For $400 every five years I’d say let it depreciate and replace it. Still gotta keep it clean though, for safety reasons. You do not want standing water and slimy deposits to build up.
But I warn anyone who cares about customer service and honest dealing to stay far away from Frigidaire appliances. I remain furious at them almost a year later for how hard it was to get them to honor their warranty.
posted by spitbull at 4:22 AM on June 8, 2021 [1 favorite]
Many mid to high grade dehumidifiers come with a built in pump to send water up and out of the unit to where you want it to go. Built in pumps are often a weak spot in dehumidifier design, but they are simple and convenient when they work right. Otherwise gravity drain it into a standalone level-triggered pump, which is what I do. That has way more power to send water out anyway.
I own the priciest Frigidaire dehumidifier, highly recommended by the unreliable NYT Wirecutter blog, which I won’t ever trust again. I will NOT recommend it. My first one arrived with the built in pump broken out of the box. It took three months of insane hassle to get it replaced under warranty and I’m not alone in despising Frigidaire/Electrolux customer service.
You get essentially the same Chinese products for 10-20% less buying a Midea or other budget brand unit. Dehumidifiers can last a long time but only if you clean them and maintain them. They are by design a wet and slimy environment and scale and deposits collect in them. I have a heavy duty unit in the basement (what the Frigidaire replaced ONLY because I wanted more energy efficiency) that is approaching 15 years of continuous prior service and works fine, it just draws too much power for my taste. I can already see the newer one likely has about 4-5 years of service to give before cleaning it becomes a futile exercise for me. For $400 every five years I’d say let it depreciate and replace it. Still gotta keep it clean though, for safety reasons. You do not want standing water and slimy deposits to build up.
But I warn anyone who cares about customer service and honest dealing to stay far away from Frigidaire appliances. I remain furious at them almost a year later for how hard it was to get them to honor their warranty.
posted by spitbull at 4:22 AM on June 8, 2021 [1 favorite]
Oh and the best part was Frigidaire didn’t want their defective unit back. They had me cut the AC cord and send a photo of the cut cord. I’m expected to dispose of it, which costs $20 at my town’s dump.
Yeah no, I’m capable of rewiring an AC cord just fine. I now have a practically unused second unit that works fine except for its broken pump. Which I don’t actually need as I gravity drain it into a powerful standalone pump anyway. I just thought “You fuckers, I paid for a working pump function I may want someday and it doesn’t work, so replace it.” But in point of actual fact I wound up with two working units, minus a pump on one I may eventually bother to repair myself, for $400 and three months (and 16 hours on the phone, I kept track) of Frigidaire runaround. I’ll eventually use the first one, and consider the $400 value of it payment for my wasted time.
posted by spitbull at 4:36 AM on June 8, 2021
Yeah no, I’m capable of rewiring an AC cord just fine. I now have a practically unused second unit that works fine except for its broken pump. Which I don’t actually need as I gravity drain it into a powerful standalone pump anyway. I just thought “You fuckers, I paid for a working pump function I may want someday and it doesn’t work, so replace it.” But in point of actual fact I wound up with two working units, minus a pump on one I may eventually bother to repair myself, for $400 and three months (and 16 hours on the phone, I kept track) of Frigidaire runaround. I’ll eventually use the first one, and consider the $400 value of it payment for my wasted time.
posted by spitbull at 4:36 AM on June 8, 2021
To add the good thing about almost any good modern dehumidifier is that they can be set to maintain a specific humidity level irrespective of temperature. They come on when it gets above that level and shut of when it’s below. Unless an AC is set up with a hygrostatic control, you’re always adjusting the temperature to get an AC to dehumidify without cooling more than you want.
I too am curious about where the moisture is coming from. The key variable you don’t mention is where you live and what is the outside relative humidity level when you’re hitting 88% indoors, which no wonder your floor feels slimy and sheets feel damp. That’s approaching rain.
posted by spitbull at 8:32 AM on June 8, 2021
I too am curious about where the moisture is coming from. The key variable you don’t mention is where you live and what is the outside relative humidity level when you’re hitting 88% indoors, which no wonder your floor feels slimy and sheets feel damp. That’s approaching rain.
posted by spitbull at 8:32 AM on June 8, 2021
Response by poster: I found myself obsessing too much while my room sat being way too damp, so I bought this—Airplus 30 Pint dehumidifier—(which at the time was 20% off, for a total of $104) which has definitely been doing a good job removing moisture and seems to assess the room’s humidity about in line with what humidistat says. I read that, overall, the “larger” models that remove more water per 24 hours end up being better in terms of energy usage because even though they use more electricity, they don’t end up needing to be on as long as the less powerful ones.
I am currently living in Western Massachusetts, an area I’m not really familiar with weather-wise. I’m not sure where the moisture is coming from—it wasn’t like that the day I moved it, but has been pretty hot and humid outside for much of the 10 days I’ve been in this space, and for a bit it was 70-90% humidity outside, though now it is way lower. Maybe it’s just hard to clear humidity out of a space by moving outside air through it with a fan even once the outside humidity is lower and it just got sort of stuck. For the moment I’m doing a lot of dehumidifying to make sure everything is really dry and setting up more organized systems for clothing that allow more air circulation and then I’ll reassess.
posted by needs more cowbell at 9:08 AM on June 11, 2021
I am currently living in Western Massachusetts, an area I’m not really familiar with weather-wise. I’m not sure where the moisture is coming from—it wasn’t like that the day I moved it, but has been pretty hot and humid outside for much of the 10 days I’ve been in this space, and for a bit it was 70-90% humidity outside, though now it is way lower. Maybe it’s just hard to clear humidity out of a space by moving outside air through it with a fan even once the outside humidity is lower and it just got sort of stuck. For the moment I’m doing a lot of dehumidifying to make sure everything is really dry and setting up more organized systems for clothing that allow more air circulation and then I’ll reassess.
posted by needs more cowbell at 9:08 AM on June 11, 2021
Until you got your dehumidifier, basically the only consistently cool surface inside your living space has been your concrete floor. That means that water vapour has been condensing on your concrete floor for quite some time, and concrete is somewhat absorbent.
Absorbed moisture also migrates very slowly through concrete, and probably even slower through the laminate overlay, so it could well take longer than seems reasonable for your dehumidifier to pull the accumulated moisture out of your floor. But you should find that as time goes by you're not needing to run the unit for as long to pull the interior humidity level down to something more reasonable.
posted by flabdablet at 8:51 PM on June 11, 2021 [1 favorite]
Absorbed moisture also migrates very slowly through concrete, and probably even slower through the laminate overlay, so it could well take longer than seems reasonable for your dehumidifier to pull the accumulated moisture out of your floor. But you should find that as time goes by you're not needing to run the unit for as long to pull the interior humidity level down to something more reasonable.
posted by flabdablet at 8:51 PM on June 11, 2021 [1 favorite]
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posted by jonathanhughes at 12:59 PM on June 6, 2021