Dehumidifier

[AGS]

Living in such a small space now it seems showering, cooking, etc. is raising the humidity too much, even though it’s pretty dry outside. I need to get a dehumidifier, but I need to know are they safe? I know at least some are, but is this something where I’m going to have to research to find a safe one or are any fine?

 

[flyzipper]

What's the humidity in your place when measured after the peak of cooking and showering normalizes?
... and what's the typical humidity and outdoor temperature this time of year?

 

[AGS]

It’s staying around 60-62% right now. When I run the AC, it lowers it to 51% or so. But it is starting to get too cold to run the AC. Opening the windows has a similar effect but I live in an apartment complex and smells start to come in from the neighbors so I have to close them. Oddly running the heat increases the humidity back to the ~60% level.

I live in AZ and currently the outside humidity is 35%. The average for Nov-Dec according to Google is 28-35%.

 

[Pat H]

@AGS-- Please tell me about AZ..
Currently dreaming about returning to the SW, but I don't want to go back to Las Vegas, and my husband doesn't really want to go back to CO... so we're looking at NM, AZ and TX. Thank you...

 

[AGS]

@Pat H I think it’s really nice here. I recently moved to Tucson from Phoenix and compared to Phoenix there is so much wildlife here. It’s very quiet which I think is peaceful. No extreme weather. Phoenix has a lot more stuff to do but Tucson has a lot more hiking opportunities/other nature activities.

 

[flyzipper]

It’s staying around 60-62% right now. When I run the AC, it lowers it to 51% or so. But it is starting to get too cold to run the AC. Opening the windows has a similar effect but I live in an apartment complex and smells start to come in from the neighbors so I have to close them. Oddly running the heat increases the humidity back to the ~60% level.

I live in AZ and currently the outside humidity is 35%. The average for Nov-Dec according to Google is 28-35%.

60% is on the high end of the ideal range, but indoor humidity typically normalizes with outdoor humidity unless the home is highly sealed (as in passivhaus standards) so the elevated levels may only be transient as the seasons change. I'm only belabouring this aspect because I don't like seeing people spend money on things that might not be necessary or which deal with transient issues.

That said, before investing in a dehumidifier, do you already run your bathroom and and kitchen vent hood when using those areas (and are they vented outside)? This could reduce the humidity at the source and eliminate the need for supplemental dehumidification. Closing the bathroom door and opening a bathroom window can also help.

Now, finally to your question A condensing dehumidifier may contain concerning materials (you'd need to confirm with an individual manufacturer for the specific unit of interest), however by their nature they don't operate at high heat, so they're more akin to shopping for a refrigerator (which also has a condenser) than an oven. Risks, if any, would manifest during a failure state rather than during normal operation. As with any new appliance, I'd run it for a while in a separate air space until its "new" smell dissipates.

My experience with dehumidification was noise and heat (they add a bit of both to the environment they're in). Also think about how frequently you're able to monitor and empty the water that accumulates (there's a shutoff switch, but smaller units may need emptying throughout the day, vs larger units which may be once per day or less).

Finally, you could take a couple approaches if you buy one for your small space. Frist, buy one that's sized for your space and let it run on a moderate fan speed using its automatic sensor. Second, buy a larger capacity unit that you could run on its high setting while cooking and showering to quickly reduce humidity levels and keep it off at other times (such as when you're trying to sleep or working).

 

[AGS]

It’s just scaring me because of potential mold growth. The windows also keep fogging up in the morning. We did just get out of monsoon and the storms were intense, way worse than what I’m used to in Phoenix.

I do have exhaust fans in the bathroom and kitchen but no windows. I’m embarrassed to admit this but I didn't start running them until I found out about the humidity.

It has been very slightly less humid today. Like 57-59%. Not sure if it’s coming down naturally or if it’s residual effect from running the AC yesterday. I can’t do that anymore, and I think I will have to start running the heat, Widget has poor circulation and his poor toes are cold.

Do you have any idea why turning on the heat is actually increasing the humidity?

 

[flyzipper]

The windows also keep fogging up in the morning.

That could simply signal that your windows aren't good insulators (single pane, or leaky double pane).

A single pane of glass can become a cold condensing surface as outdoor temps drop overnight (pretty common here during Canadian winters).

This can be made worse by tight fitting window coverings that don't allow warm indoor air to circulate over the pane.

Using a dew point calculator and estimates of your environment (72F and 60% humidity), the windows will condense if their surface hits 57F (possible if your overnight temps are dropping low enough).

Do you have any idea why turning on the heat is actually increasing the humidity?

Yeah, that's a weird one, and clearly demonstrates that you understand warm air can hold more moisture than cold air (said for the benefit of others who may not), so relative humidity reduces (for a given absolute value) when the temperature increases.

Is your heating system pulling in outdoor air while it's running (combining ventilation functions to bring in fresh air)?

I’m embarrassed to admit this but I didn't start running them until I found out about the humidity.

As much as I harp about the importance of indoor air quality now, I'll admit that I didn't habitually run those fans until I had birds, but now it's a reflex.

 

[AGS]

I’m not really sure. But it was at 59% then when I turned the heat on it shot up to 65% and it definitely felt humid. Then down to 61% after it turned off and second time it cut on it only went to 63%. I would say it might be an issue with the hygrometer if it hadn’t actually felt that humid.

My apartment complex was built in the 1980’s I believe. They have updated some things but I doubt they’ve done much to the HVAC system. It is so noisy too, even in a 420sqft place I can’t hear someone knocking on the door when it’s on.

 

[flyzipper]

Perhaps ask your superintendent.

If the nosiness of your HVAC running is exclusively high velocity air flow (duct noise), that might indicate a central system, whereas if you're hearing mechanical sounds then that's probably from local equipment.

There are funky things done in apartment HVAC systems that aren't common in single family settings (accidentally or internally) so it's tough to generalize.

In a typical residential system (or if your HVAC unit is contained within your unit), the ducting is usually a closed loop such that the cold air supply is pulled from within the same air space as the discharged warmed/conditioned air to keep the pressure balanced.

If your building has a central system that's discharging air into your unit, it's pulling air from someplace else, and relying on your unit to leak the increased pressure back into common areas. If you have a barometer, does the pressure increase when you run the HVAC unit? Increased pressure would indicate your unit is being inflated like a balloon from an external air source.

Speaking of pressure, apartment building pressures, and therefore air flows, are an ever-changing dynamic based on open and closed doors/windows (including your neighbours), whether the common areas are positively/negatively pressurized, the stack effect, direction and strength of outdoor winds, etc.

 

[AGS]

I’m not familiar with this topic at all, I know I have some sort of unit in the closet ceiling. It was leaking before and I had to get the emergency maintenance to come fix it since it was in the middle of the night. I know there is also the AC “vent/intake“(??) in the living room that pulls in the air, then the normal vents in each room that blow it out. No barometer. And there are no common areas here if I’m understanding you correctly, all the doors open to outside.

I did ask a neighbor and he said he also gets the condensation on the windows in the morning. I didn’t ask about the humidity specifically because I’m not sure he would have a hygrometer. But he did tell me he had a mold problem before and maintenance told him he needs to open the windows when he cooks or showers.

I’m kind of sad because I wanted to get Widget a Wingdow seat but I can see the condensation being an issue. I suppose I could get him a perch with a suction cup instead but then he would be able to touch the window and I guarantee he’d be licking and tapping on it.

 

[AGS]

Ok now who do I believe?

 

[flyzipper]

I assume they were close to each other -- do you have a 3rd to split the difference?

Seriously though...

• Add a good amount of salt to the bottom of a jar and dampen it with water.
• Use something like the attached image for the humidistat to stand on (don't get it wet).
• Seal the jar.
• Wait 3 or 4 hours.
• The relative humidity should read 75% for an ambient temperature of a typical room (73F in your case).
• Whatever difference is noted is the calibration error for your humidistat (adjust its calibration if you can, or just remember this delta).

Here's another option with visuals, but the same concept (link).

(enjoy your pizza)​

 

[AGS]

I’ll have to see if I have something like that. But I’m thinking the one on the right is inaccurate or just really slow because it has very slowly crept up to 55% now from 40%.

 

[flyzipper]

The other thought would be to put them outside and compare the reading to your current local weather.

 

[AGS]

Yeah I can try that. They are both reading the exact same temp and humidity now though so I’m thinking they are pretty accurate. The second one just took forever to get to that. I’m putting in a maintenance request to see if there’s possibly a leak somewhere causing this or some other issue. At the very least they will probably know if this is “normal” for these apartments and at that point I can see about getting a dehumidifier. This morning the humidity was at 67% for no apparent reason.

 

[AGS]

They will also know about the exhaust fans and whether they lead outside or not. I had never thought until you mentioned it and the research I did that they would lead anywhere but outside.

 

[AGS]

So maintenance is probably coming by tomorrow but I’m having so much anxiety borderline panic thinking it might be too little too late. There’s a weird dusty type smell in my room that I associate with mold. If Widget gets sick he could die. He has heart disease.

I don’t even know if maintenance can fix the humidity issue and if there’s mold growing somewhere treating it is one thing but finding it can be very difficult. And I would probably need to stay somewhere with Widget while they treat it.

And I’m conflicted on the dehumidifier because they are expensive. There are cheaper ones but then I’m sure there are quality/safety issues. And even with the more expensive ones people say they are fire hazards, increase the room temperature too much, etc. and I just can’t find much info on them being safe for birds because most people seem to have the opposite problem of needing a humidifier. I can email the companies but i don’t know what kind of toxic stuff they could have. Is it just Teflon or something else?

Im sorry for writing a novel I’m just about to cry from stress and panic. I can’t let anything happen to Widget. And now I’m crying and Widget is telling me pretty birdy.

 

[flyzipper]

Let's see what maintenance says and we'll go from there.

Dehumidifiers are as safe as refrigerators since they both use compressors, and we can find a suitable unit for your space if it's needed.

They do warm the air slightly, but during the time of year when, "it is starting to get too cold to run the AC", that shouldn't be an issue (you'd use AC when it's warmer).

Cuddle Widget and keep us updated.

It'll be ok.

 

[AGS]

Thank you. I’m watching YouTube videos right now and trying to calm down. I know there’s not really anything I can do tonight anyway.