Dehumidifier Testing and Calculations: How/What/Why of Dehumidification with Santa Fe Ultra 

Great video! Love the tip about using the outside air intake of the dehumidifier to slightly pressurize the house to prevent air infiltration!

This exact piece of equipment will be going in my home in about 2 months in the Atlanta area. Your timing is perfect!!!!

Wow! Great teacher! And very interesting. I have some family with a beach house on a slope where the first story is again set a hill and often can see 70% humidity. I love the step by step formula breakdown!

Best video I've seen ever on ventilation in florida.

*We liked it **Fastly.Cool** so much in the basement, we bought a second one for the main level. The amount of moisture it pulls out of the air is astonishing.*

I wish the guy from Crawford Services, who had sold me my HVAC unit ,was AS knowledgeable as this guy. Subscribed.

Easy to setup and powerful 👌.Connects easy to Google home assistant, voice commands work well.

Super great presentation and content.

Thanks for this great video. Highly informative !

Sitting in climate zone 5, looking forward to your future discussion on humidification! But still a useful video.

Excellent stuff dude

I'm in Houston, and really really enjoyed this. Think I know what I'm about to purchase.

Phenomenal Video! Thanks!

Thank you!

"Thanks for comming to my crawlspace" subscribed

Very informative video! I got a little bit confused on the calculations at 12 minutes 30 seconds. I think you meant to say density of air is 0.075 lb/cu ft instead of 0.75. Thanks again for the information.

Love your videos! Quick question, what kind of flexible duct did you use or recommend to use to decouple dehumidification or even HVAC equipment from metal duct? I have looked into vibration isolation devices, but they are terribly expensive. Just trying to accomplish better acoustics affordably. Thanks.

Hi! Great program, thank you. I have a question re mold and humidity, how do you deal with this issue and also can you do deep clean the dehumidifier. I thank you in advance for your response.

Thank you for sharing. Awesome content. 👍

Couple of years late, but I did watch this a while ago, the first time. Great information and it helps me with a humidity problem I am tackling in, of all places, Arizona. During monsoon season, the humidity in the house is unreasonable and the flooring is buckling. Anyway, question about your crawl space and your system. You are intentionally pulling air from your crawl space and directing it into the living space. Radon is a concern in homes and it starts in the crawl space. We try to keep it from entering the home by pulling the soil air and directing it outside. What you have is doing the opposite. Do you have thoughts on this/have you tested for radon? Thank you.

Hello I just buy a aprilare e 130 and i was asking my self if i need an air conditioner system to run my aprilaire of it can work stand alone only de humidifing Thanks great video!!

Great video. I'm in Louisiana. What settings would you suggest on venting and fan on a new 2600 square foot home with only my wife and I? I did spray foam the roof deck with open cell, so the house is pretty tight. We are both retired so at home most of the day.

What they don’t tell you about before home dehumidifiers: Home humidity needs to be looked at like home heat energy, meaning what things are in you home that can be causing the high moisture? Do you have a very leaky house? Do you have a very tight house? Is your AC pulling away the humidity from your home as it should? When your HVAC blower is running does it create a negative pressure in your home? Do you have a water leak in your home that you are unaware of? Do you have an excessive amount of plants in your home? Do you run your AC too low or too high? Do you have a crawl space and if so does it have a vapor barrier? I’ve found that if you can address these issues first, it could lesson your need for a whole home humidifier. Don’t obsess over getting your home to 50 or below relative humidity, when 60RH to 50RH are fine numbers to have as well. If you wanna know what 35 RH feels like, I can tell you, because I’ve had my Aprilaire unit for 2 years now. 35 RH at 72 degrees feels like a dream when coming in from hot outdoors weather, and getting out of a hot shower. The feeling of water evaporating from your skin so rapidly is an amazing feeling, absolutely so, but there’s a catch 22! Your skin, eyes, nasal pathways, and throat suffers from the lack of moisture in the air. It’s something you don’t notice right away, but when you wake up in the mornings with dry eyes, dry mouth and throat you soon realize how some moisture in the air isn’t such a bad thing. Another thing that happens with a wood construction home is the wood will sometimes shrink. We all experience this sometimes when some doors closes well in the winter but not so well in the summers or vise versa. It can literally cause your wooden boarders (crown moldings) to shrink enough that it cracks. The bottom line is purchasing a whole home dehumidifier can be a life changing event in a good way, or it can leave a sour taste in your mouth. They are not for everybody who can afford one. Mine averages about 750w when in use, and it does have a noticeable compressor hum like all heat pumps have.

Hello Corbet, I've been watching you for some time and first- thank you for all these videos. So much to learn.. Question(s) for adding the dehumidifier to the supply; 1: does the positive static pressure from the HVAC cause (meaningful) backflow in the humidifier? 2: does it the dehumidifier meaningfully increase the static pressure putting extra strain on the air handler?

Thanks for the video! We live in Alberta, Canada where we have major swings in humidity. I’ve installed a new VARIABLE-CAPACITY GAS FURNACE with a MERV 16 filter and HRV system in a 1960s home we’ve been slowly renovating. We’ve been working on sealing the house up, and have gotten it to a point where the HRV is required. We don’t have any cooling in our system yet (we plan on putting a heat pump into the system in the future, which our furnace can accommodate). My question is, with our HRV dumping fresh humid air into our return duct, should we hook up the dehumidifier to pull from below the HRV supply and dump it back into the supply before the MERV 16 filter so it can still filter the air coming in from the HRV? Thank you for all the great information you two are putting out!

Great video good sir. Here in hot humid Southeast Louisiana, will will be installing this into a totally encapsulate unvented attic. I was contemplating zoning my dehumidifier to do the attic as well as the house. Also bringing in my fresh air from outside the home/attic space. Just curious what's your crawlspace psychometrics look like? I'm assuming all your ductwork is uninsulated in down there? How are you controlling the humidity levels down in the crawlspace to prevent condensation on your duct and equipment?

GREAT VIDEO! quick question, i understand you are pumping the air out of the dehumidifier into the whole house supply plenum (after the ac) now what about the return duct? Where are you pulling your air from? did you build independent returns in extreme points of the house? Would love more detail on That! Thanks again!

Since you are ducting into the HVAC supply, will you need to ensure the central air handler runs whenever the dehumidifier runs? Won't this be more costly to run the central blower instead of keeping the dehumidifier supply seperated?

I like the explanation you provided in your video. There is one thing that is of concern is bringing into the living area any air from the crawlspace. Viewing it from an indoor air quality (IAQ) standpoint, the crawl space is often a source of rodant droppings, mold spores, the possibility of Radeon, and odors of different types. Yes, a HEPA filter can remove most of the bad stuff but won't do anything for Radeon or other odors. It would be best to bring in fresh outside air for the fresh air intake port on the dehu. The crawlspace should have its own dehu without a fresh air makeup.

greetings. thanks for sharing. we have a home on the beach in central california where the humidity is always too high. If we were to install a dehumidifier in this home, would the water that is produced be ok to water the outdoor landscaping? we live in an area where water is scarce and very expensive, so if we could use the water from the dehumidifier we could solve two problems. Do you think the water would have too much salt to be helpful?

Excellent video! How do you relay the home humidity levels outside the grate to communicate with your UA sensor in your grate?

Fantastic explanation as always. Loved the numbers. How does ERVs perform instead of having a dedicated dehumidifier system as you have

Great video, you are an amazing teacher. I see the outlet of the dehumidifier goes to the outlet of the HVAC air handler. Wondering where the inlet to the dehumidifier comes from? I will install a dehumidifier and new HVAC soon. One vendor recommended taking the air off the inlet to the HVAC air handler, while another said it is important that the dehumidifier have an independent return from the house, which of course is more difficult. If you see this, I would appreciate your thoughts.

Great you have supplier in phils

Can/should you put one of these in a crawlspace if the crawlspace doesn’t extend to the whole home and is more adjacent to the basement? I’ve been looking at ventilating dehumidifiers as I’m trying to remediate moisture issues in the basement as well as average 60% humidity in a dual zone system. One zone sits over the basement (and a portion over a crawlspace) the second zone sits over the garage. Looking for options.

Best Video I've seen on this topic. Thanks so much. I'm building a new home in central FL and was thinking this might be a more affordable upgrade with a better ROI than stepping up to top of the line Variable Speed systems since the main attraction to me is making the house more comfortable. I also absolutely love my Ecobee Thermostat which I believe will control a dehumidifier. Am I correct that the Ecobee's work well with this type of setup? Also does the Air Handler have to be on while the dehumidifier is running or does it push enough air by itself?

I’m desperately trying to figure out how to dehumidify with a split system in place. I am in Austin, TX, and it’s essential. I was thinking of putting a couple feeding into the medium static boxes on each side of the house. the supply coming out are very small and there are multiple in these boxes sold by like Mitsubishi and Daikin. Do I have to decouple my dehumidification? I’m going to be on Solar off-grid and trying to optimize.

Can you take the fresh air from an ERV fresh air discharge side, (not the stale air exhaust to outside vent), and put it inline or on the intake side of a dehumidifier unit? I live on Texas gulf coast, it’s pretty much high humidity year round, 360 out of 365 days. We are building a recording studio with open cell insulation on the outer wall of the double walls, so it’s air tight.

I'm a custom builder, and chose to run the Ultra Aire SD-12 in my own home here in SW Florida. It is a split unit, so the compressor is outside, and we are pulling in fresh air from outdoors. I figured the heat load we're introducing from bringing in outside air is being (at least partially) offset by not having the one piece unit introducing additional heat load inside the house. Or at least that was the theory. :-) We've got two dogs and a cat, so a lot of fresh air was important for indoor air quality. (Update, UA is now Santa Fe and they disco'd the SD-12...)

Thanks for this, Corbet. My home has a concrete block foundation so it's not sealed - would this still be my solution for my humidity problems or am I supposed to be looking more for ventilation solutions? Thanks!

Great video, you mentioned florida. What’s your take on a ventilating dehumidifier vs having an ERV system for balanced ventilation and a separate dehumidifier (not ventilating)

Great video! Question about the ventilation part. So I would think you would want separate control of ventilation air and recirculation through the dehumidifier. The April Aire E100V with 8190FF provides control of either recirc or ventilation that it auto electronically controls based on settings. The SanteFe you show appears to just bring a mixture of recirc and ventilation air dependent on a manual damper on the ventilation input. Is this true and what are your thoughts on this. I like all features of the SanteFe except not having separate control. Thanks!

If you have a variable speed air-conditioning system in your house would you still need a dehumidifier?

I actually watched this a second time and came up with a new question. When the Utra-Aire dehumidifier runs, is there some control line from the Ultra-Aire back to the HVAC system to run the main fan to distribute the dehumidified air throughout the house?

Hey corbet How long does your dehum run on average in a day. I was curious in real life experience as i have a dedicated dehum for 3 yrs like you but i dont have as air sealed house, house size, etc. As i tighten up my house, im always looking how it affects my dehum run time, so i assume you might have the target dehum run time. I expected the dehum to catchup faster after a shower than 1 to 2 hrs on a 90pint 1,000sqft in birmingham. Your info has gotten me into home performance, thanks Shelby

Can dirty filter trip the breaker on these?

Looking at this exact unit for my home in the near future. Now if we could just stop opening the windows when it's raining outside!

I sure would appreciate a line diagram of how you "plumbed" the Inlet and outlet of the Dehumidifier to your heat pump's duct work. I have watched other videos about the same unit, which I am considering buying and I know some people had issues with the way the manufacturer had it being connected below the heat exchanger/coil of their heat pump. Sending warm dehumidified air across the coil and causing freeze ups. Could you post a PDF of a schematic?

By slightly opening the fresh air input duct, you are satisfying one objective I have for some dehumidification for the basement/crawlspace. What about the attic? Do you supply dehumidified air to the attic or use the method to create a slight negative pressure for a conditioned attic to help manage the humidity in the attic?

Can you link the drill bit and sized plugs. I have had challenges finding matching plugs for access points made in ducts. I’m in Florida and we primarily have fiberglass duct boxes and flex hose ducts.

I've been watching several of your videos and I am aware that ductless mini splits do not dehumidify well but you made a comment that utilizing a ducted air handler "mini split" was better and that you would discuss this in another video. Can you point me to this video or where I can learn more about the differences in latent heat removal between the two systems. I understand I can read some of the published data but want to understand the control strategy and science behind this.

is the fresh air inlet able to be filtered?

Nice explanation - can you share where you got your Santa Fe humidity wheel?

Thanks for the show and topic. I'm building in a tropical location in Australia. I'll build in a dehumidifier however am wondering if one intake point and one exit would be adequate to dehumidify to whole house. Thinking humidity would equalize throughout the house.

How do you like the MD33? I have a 2 story home in Central FL. Upstairs is normally around 60%-65%. One of the bigger units like you have in the crawl space isn't really an option for my home.

Very cool thank you. I have a 1840’s house in MA that has like 80% RH in the basement since I started monitoring it in January. There’s rot damage down there in structural members which I’ll be repairing but I also wonder if and at what point in the process I should get something like this. Just opening the door (walk in basement) drops the RH like 15%. So maybe I just need to ventilate more for now. Half of the basement is still dirt floor. So. You know. Lol

You just briefly mentioned the MD33...how is this working for you? Would this be a viable whole house dehumidifier for a tiny house or small home? It seems that being able to wall mount it would be a huge space savings plus the drain line is a perk.

Great video as always, been a long time viewer and fan of the channel. I recently purchased an aprilaire e100 and was trying to determine the best course of routing the dehumidfied air into my ductwork. Can someone with ductwork experience help me out? I am tryning to figure out how to duct my dehumidfier into my supply side but am concerned about back flow. I have a supply plenum that I can duct into but I was concerned that just pumping the air into the plenum would push air back to the AC return which my Dehumidifier return will be near. Alternativly I can maintin the seperate return idea but wye the dehumidifier into the return side and maintain a better flow.... Am I over thinking the flow?

Questions. A) do you run the Mitsubishi fan while the dehumidifier is on or is the fan in the unit able to circulate the air? B) 40 percent humidity in Georgia is fantastic how do we determine what’s appropriate for us? I’m in Illinois at 50% with a 69 degree home I would like to get to 40% and raise the set point to 72 degrees. Does the heat from the dehumidifier condenser cancel out the cold evaporator coil that’s doing the work?

How can i verify that my unit (same as the one here) is actually working properly? My production builder's contractor installed it and they did a bad job on the HVAC so I don't have much confidence this was done right either. We have a long return duct (about 20ft or more) to the unit. They originally had the return installed in a tight kitchen/mud area corner next to the garage entry door and a side exit door. It was a bad spot so we had them move it which created a longer duct but not much choice.

Hi Corbett, could you explain the math for pints/hr please? You are multiplying by 1/8 then multiplying by 8 a little later in the equation, it would seem they cancel? Is the pounds per hour the same as pints per hour as 1 pint is one pound? Forgive me for being nit picky, your tuition is fantastic I just got mentally stuck at this equation

Hi! I have a heat recovery system in my house in the UK, it's a very old house with some mud and straw (cob walls) the humidity outside is 80-95% and inside we manage to get 60% am looking into a inline dehumidifier into the system have you got any experience with how it affects a heat recovery system

Would you always recommend installing a whole house de humidifier if replacing the hvac system in an existing home?

Thank you so much. Very informative. I have a question for you. For homes in the north Georgia area, would you recommend in ERV with a whole home dehumidifier or just a dehumidifier with a fresh air intake similar to what you have in this video? The equipment will be going into an unconditioned attic.

Ok can you tell me exactly how you have this running, is it running in the ductwork for the ac system without the ac being on and if so where are you pulling in coming air from is it in the house or outside only?

Could the water from the dehumidifier be further harvested/processed for culinary or emergency uses?

Why would you not want to pipe it directly into the return of the a/c? I understand its not ideal (say if the fan of the a/c is off or something, but will it actually hurt anything? I have a situation where I can only really access two spaces of the return ducting, the supply isn't wide enough and there are trunks going upstairs and one going to the main floor, and above the a/c unit the trunk isn't wide enough to fit 8 or 10 inch collar.

For the humidifier to work do you need to leave your fan running consistently?

This seems to be the best place to pose a dehumidifier question, since viewers are not afraid of tech and numbers. I have a common Hisense portable unit of the 50 pint persuasion, which draws 600W when the compressor runs. This concerns me. Almost all the Wattage is exhausted through the top as hot air, which serves to noticeably warm the area, and has to be evacuated by the central AC. I propose to enable the pump and send the condensate to a radiator mounted above the unit, and then let it drain as before, to a floor drain or laundry tub drain. The goal would be to capture some of the heat before it could warm my home. This seems so obvious that I wondered why no manufacturer builds in such a feature. Could it be that doing so would not improve the efficiency rating as it is measured; even though it would benefit the consumer? It would be hard to explain why the consumer should pay an extra hundred dollars, and very few customers would be savvy enough to understand it. I'd buy it though. I'd even buy an add-on unit, IF the idea even works. Any thoughts? Keep in mind that I'm envisioning capturing perhaps half of the 600 Watts of heat, and that condensation is not a concern.

What happens in the winter when you need to add humidity to the air?

You didn't really talk about how the dehumidified air (from either dehumidifier) gets into the living space other than to say it is piped into the supply side (duct) of the main heat/AC unit. Is the main heat/AC air handler running constantly (maybe at variable or stepped speeds) to carry the dehumidified air or is there a 1-way damper to ensure the dehumidified air doesn't travel backwards as well as forwards in the main ductwork? I suspect the air handler is running constantly to (also) provide constant filtration and de-stratification regardless if there is a "call for heat" or "call for AC".

Can you set these dehumidifiers to run continuously instead of running based off of the humidity?

How do you like the Airthings system?

would you then connect an ERV on the ventilation side?

Do you still need bathroom exhaust fans with this setup? I'm in FL and the home I purchased doesn't have exhaust fans in the bathrooms. I was going to just have them installed but I'm considering a whole house dehumidifier instead.

Since you've added a whole-house demudifier, do you still think the ERV was the better call over the HRV? It makes the systems a little more redundant, which the engineer in me loves, but it also adds a bit more cost, where I've found HRVs are cheaper than ERVs. It also seems that HRVs are more widely recommended for bathroom exhaust, whereas ERVs are just slightly more questionable.

If the dehumidifier supply is ducted to supply of air handler is there a damper to keep the ac from blowing back through dehumidifier? If so if both are running at the same time can the dehumidifier over come the blower from the AC ?

I'm sure your explanations are good, but some people are better with a written/drawn explanation. Consider adding some white board time or animations to put your videos over the top and reach more folks. Some of what you were saying about the temperature before and after the ducts and which ones were connected where was just too much without some sort of diagram. ***Edit*** Kept watching, and voila, visual aids. Would still like to see a diagram of the ductwork and airflow you're talking about.

CFM is in minutes, but your computation is in hours. Did I miss where you are converting these quantities (or is it baked into the 4.5)?

What should I set my humidity for my house at?

What rope suspension kit/parts did you use for that?

Can I use a dehumidifier when I have a ductless mini split system?

The way this is explained does not make physical sense to me. How at time stamp 8:49 does a "heated" output of the dehumidifier cause a 90 plus degree environment to decrease to 76.7 degrees??? I have a floor-standing unit in my basement and am researching to install this type of ducted system. However, even the floor unit directions indicate that where you run this 70-pint-per-hour floor unit will have an ambient temperature increased by about five degrees. I have observed this effect while running the unit at max output. So how are you saying that your unit is sending heated and dehumidified air into what is evidently the duct with the supply or post-conditioned area, and having it magically be decreased to below 90 degrees?. (Are the "supply" and "return" terms being swapped here???)

So duct the dehumifier supply into the AC supply?

I still find it all complicated but I’ll get it eventually...I hope

You shouldn't have been moving the sensor used in the duct. Reason being the wind are vectors or forces in a direction. As physics would dictate moving the sensor tip towards or away the direction of the wind flow can minus/divide or adds/multiply respectively force wind. But then again air tightness is critical and helps in out air flow

How can I find someone in the Pee Dee part of South Carolina who knows how to add this unit correctly?

Does the dehumidifier add heat to the air

What's the point of running AC at the same time? The whole point of the dehumidifier is to save energy by not running AC during warm/cool "shoulder" seasons.

@12:23: 0.75 * 60 = 4.5? I get 45.

"80f 60% ....... is a ridiculous number" lmao. just keeping the humidity down to that would be nice.

@14:00: So you divided by 8, then multiplied by 8. Hmm. I think I can save you 2 steps.

Beautiful equipment sitting on a stack of concrete brick 😂😂 cmon

imperial units are dumb.

This video is 1/2 blabbing. Obvious a salesman acting as an engineer. Where is the dehumidifier test ?

What if I don’t want my AC coil to pitch in and help with drying? Just curious, will my AC coil last longer if water is NEVER ever allowed to condensate on the coils? No mold keeping them clean forever?😂. I dunno maybe 30 year coil life? If I sacafrise the smaller less expensive dehumidifiers coil. Either way I’m sacrificing a cooling coil. But at least this way it’s the smaller coil that’s easier to pop in and out to replace. Any thoughts from anyone? This is just theory.