Humidity Basics
ฝัง
- เผยแพร่เมื่อ 2 มิ.ย. 2024
- Bryan covers some humidity basics, including the difference between relative humidity and total moisture content (in pounds or grains).
First of all, air has weight and takes up space. At sea level, the air pressure is 14.7 PSI due to the atmosphere, which consists of nitrogen, oxygen, carbon dioxide, argon, some more trace elements, and water vapor. The amount of water vapor in the atmosphere is variable based on different environmental conditions, and it depends a lot on temperature.
Relative humidity refers to the amount of humidity there currently is compared to how much humidity the air could possibly hold (100% RH or saturation). The point of 100% RH or saturation is also known as the dew point temperature. Once the air reaches saturation or the dew point temperature, it can no longer hold any more moisture. We keep evaporator coils cold so that the air reaches the dew point and has to drop some moisture as it cools; that moisture then drains out as liquid water.
It's also worth noting that water vapor is lighter than air and travels up in the atmosphere; from there, it hits the dew point and forms a cloud.
Warmer air can hold more moisture before saturation is reached. Air can hold less moisture on a cold day, so you could be at 100% RH and still have less total moisture in the air than on a hot day. You can think about tea or coffee: high amounts of sugar won't dissolve in cold tea or coffee, but more will dissolve when you heat the tea or coffee.
Humidity is a huge driver of comfort or indoor air quality. Higher humidity levels make it harder for us to dissipate heat through sweat; our bodies aren't able to dissipate heat via evaporation as easily. The target relative humidity range from a comfort standpoint is typically between 30 and 60%. From an IAQ standpoint, it's typically good to stay between 40 and 50%. Moisture buildup due to conversation in homes with high relative humidity can lead to microbial growth and present a health hazard.
Read all the tech tips, take the quizzes, and find our handy calculators at www.hvacrschool.com/.
God Bless this guy! . Love !!! -- His sound quality alone exceeds most. I'm convinced this guy does his homework on everything in life. This was so relevant and helpful to anyone wanting to learn about humidity.
Excellent video, thank you for sharing your knowledge.
Just about one of the best, time sensitive explanations of this topics, both dealing with the physics, the human aspect, and the technological for HVAC. TY.
This guy deserves a medal! So simple and straightforward, thank you good sir!
This channel is going like a rocket.... all the way up
Beautiful. Thanks for this information.
Man, you're amazing! Great lesson on the basics of moisture in the air. Thank you!!
Great stuff and very well explained. Thanks!
Straight to the point. Good video!
I’m an graduate from GTCC’s accredited HVACR program and this is great stuff!! Keep it up man. It really helps when I need a quick refresher on a subject and you hit every key detail.
thank you very much . You are easy to understand and so helpful !
I understand. Thanks for the video. Thumbs up. 👍
Excellent explanation. Thanks a bunch 🙏🏾
Tea / Coffee was a wonderful analogy.
An excellent video with a clear and concise explanation, thanks.
Super Simple explanation of Humidity!👌
Great video
just what i was looking for, thanks!
Thanks for your emazing video👏👏🌟👍👍💗
Nice and clear, now I understand.
I’m old but now I get it thanks to your excellent explanation. Thank you👍
Good job! 👍
Nice job!
Awesome 🤟 explanation man!!!
This was really helpful, thankyou 🙏
Good information. Thanks : )
The best explanation of humidity what I found..
Thanks! :)
I did enjoy myself thank you.
Hi. I found your channel whilst looking for an explanation as to why my thermostat says it is 71 in my home, but the humidity is 80%, and I do not feel all that cool. Normally, at 73 F I start to feel a little chilled unless I am doing some sort of physical labour. Here is the situation. Maybe you can advise me what is happening?
I lease an approximately 905 sq ft home that was built in 1926. The owners had an all electric HVAC system installed August '23. My heating bill last Winter was outrageous, and a friend told me that was because my furnace is electric. I had always had gas before this, and my bill was never remotely that high---close to $300 before I dropped the temp to 59 F and kept it there 24/7. Even after dropping the temp to 59 and feeling quite cold in here, my heating bill only dropped to about $240. I was so chagrined.
Then, the hot and humid weather began (I live in the south). I feel hot in the house even though the HVAC is set to 71 and reads a temp of 71. I have little table top thermostats in each room of the house. No two areas have them same temp, but all areas have pretty high humidity---talking about 77%-80% as of May 2nd. At 71 I expect to feel uncomfortably cold, yet I feel hot and oily from the humidity. All windows and doors are kept closed. I am nervous to see what my upcoming electric bill will be. How can the temp in the living room, for example, read 71 yet the humidity read 80% ? The HVAC thermostat is in the living room. It seems to me that if the temp is really 71, the the humidity should not read 80%, and I should. not feel uncomfortably warm and oily from the humidity.
I am worried because the temps here will soar into triple digits soon. We managed to squeak by in April without any triple digit days, but I think that is because most days were either overcast with rain in the forecast, or a high pressure system had moved in and dropped the outdoor temperature to a very comfortable temp in the lower to mid 60s. That is already changing. We are already getting temps in the mid to high 80s before the heat index is factored in. It is about to turn really hot soon.
I would like to figure out what is going on and if there is anything to do to fix this problem. Thank you!!
very helpful. Thank you
I just want to say I surely appreciate your valuable time that you take out your day to give us upcoming techs the Juelz needed to to be a great technician i surely learned more from you then the school I attended to secure my certification I just want to say thank you... I love the training you provide for your techs your awesome would love to work for you and that's funny coming from me with my boss mentality my goal is to hopefully be a competitor of yours someday but the meaning of me really writing this is my company just hired a new service mgr can u believe this guy is not allowing us junior techs to attend union school anymore says we wouldn't learn anything from there smfh I'm so pissed so this is why I appreciate you thnx bro keep the knowledge coming please if you get a chance can you go over electric heaters ohm testing amp reading isolation of elements etc... would be much appreciated
Interesting! 👍👍
Thanks a lot. It was really helpful
Very helpful discussion. Thanks.;
Love this!
very good explanation, thank you 👌
Good job
Excellent explanation. People tend to mix up relative humidity with "absolute" humidity.
He could've used some ratios just to illustrate how relative humidity can change with temperature, though.
Best explanation ❤️
Man you’re awesome.
Great explanation. Thanks.
Thanks.. now I understand bc my house is so humid and hot and my central air isn’t working well at all so it’s really muggy and I feel very sticky
man you are amazing ..... i work in petra engineering industries and i anderstand what all you talking about this video>>>>
Thanks!
I’m from Thailand thank you for this lesson.
So glad I found your channel recently. I really enjoy your videos.
Should the temperature of the evaporator coil, be the same as the target indoor dewpoint temperature?
It depends on the dog
Thanks now i can can undrestand IT, There i one ting i Wonder about, Hvow can i calculete the dew point ?
looking forward to Your ansver
I'm wondering what your thoughts about running a standalone (plug-in) dehumidifier in your home in. This has been recommended on several sites but I'm wondering the true value of it. I certainly understand that relative humidity over 50% starts to get uncomfortable and that lower humidity is good and can allow you to even raise your temperature setpoint. However, the waste heat from the compressor is being dropped directly into my home (albeit the basement). this introduces an additional (and considerable sensible load) to the home. I haven't measures the flowrate or the temperature gain but it is normal fan speed over a 3" by 15" opening (0.3 ft^2) and the temp out is in the high 80's.
Thank you
Very simple 🔊
Thank you❤️
Thank you! That was really comprehensive and helpful. How does turning on the air conditioner in my room affect all these factors? I'd really appreciate if you could clear that up for me.
The A/C removes the heat and humidity from the room
Easily explained... Thanks
Glad it helped
So if I am running my air conditioning during the summer the air flowing over the evaporator coils is dropping its due point and this is why we have condensation. However, wouldn't this mean that the supply air is at 100% humidity and would this affect our ability to sweat? Or because the amount of water in the air is low regardless of the relative humidity because the air is cold, that it would not hinder our ability to sweat?
Can you do a video on Ultrasonic Leak Detector?
Your thoughts and experience with it Good, Bad, Or Ugly
Compared to heated diode
Trash.
I'll be starting as an HVAC apprentice in a couple months, and from my physics background I think this video was aboslutely awesome. Your analogies are on point, they really help me understand the important concepts. Thanks!
Best!
Loved it.. Thank you sir😊😊
Keep watching
It is wrong to say that air "holds" more moisture when it is warmer. Air does not hold water vapor. Air is a mixture of gases, including water vapor, not a sponge. RH is a measure of how much energy is available to evaporate water relative to the amount of energy it takes to saturate the air with water vapor. Saturation is the point at which the number of water molecules leaving a liquid water source (evaporating) equals the number of water molecules (in the form of vapor) returning to the liquid water state (condensing). Higher temperature is higher energy, hence more evaporation. 30% RH means the energy available for evaporation is 30% of that required for saturation. Further, the "dew pont" is the temperature at which condensation occurs. To prevent condensation, the temperature must kept higher than the dew point. Window surfaces colder than the inside ambient air will condense the water vapor in your home when they are below the dew point. When the inside relative humidity is higher, the dew point gets closer to the ambient temperature so the window surfaces have to be less colder than the inside air to form condensation. When the relative humidity is 100%, the dew point equals the ambient temperature so any drop in temperature will cause condensation. In your house, condensation would recuce the amount of water in the air and thus lower the ambient humidity if there was no more water being added to the air and condensation will stop, but then the job of your humidifier is to keep adding water so condensation continues, potentially causing damage to window frames and inside walls and ceilings.
So do CHWTR AHU’s use re heat coils to control humidity? Just wondering cause we recently found one with no steam at the re heat coil and room was very cold and ductlines were saturated with condensation?
Let it rain! Rain dance!
Bryan Orr - you are one talented teacher! I had zero interest in HVAC but now I think it's the most fascinating subject there is.
That's a very kind thing to say
There's an award category in it's own right!⛡
Dew point = The temperature at which moisture condenses
And this is why you do load calculations.
hi i have a problem in MRI machine room the humidity is very high it temperature 16 degree c and return air 27 degree celsius plz reply me
Will dew point limit supply air temperature leaving an evaporator?
My ac handler is inside the closet. The door is close. The door is solid has no hole. I found a pin hole after the handler in the insulation. I put a tape on it and now I have grow on the insulation. A friend suggested to change the in dilation and make it better i sulfate. What you digest?
If this is the way you teach Me. Orr, I want to enroll at your school. Where's it located?
Does too much of rain, makes a hot Temperature country humid ?
The next time your windshield fogs up, take a moment to think about the temperature and relative humidity on the two sides of the glass.
Good tip!
The greater the difference is between dew point and evaporator temperature will determine how much condensation there is?
Yes, provided there is little or no carryover due to excessive face velocity (airflow over coil and fins). The closer the ADP (apparatus dew point) is to the DP of air entering coil, the lower the SHF (sensible heat factor) of heat absorbtion will be, therefore, the more latent heat, hence, more condensation. But at higher airflows, some carryover does occur, which adds some of the latent heat back into the air leaving coil due to friction drag and evaporation. This is wht matching coil size and blower speed is somewhat critical to proper humidity control in different climates and under different cooling loads.
2:31 so i have too much moisture (actually its like rain) on my windows but on the INSIDE that got build up during the night (in winter). I would like to know what is going on in my house because the walls have mould signs. I must say there's no thermal insulation on the walls and the windows are single glass. Thanks
Plus one. Want to know the same thing…Anybody else have an explanation for this?
Can mold grow when it’s 57 degrees outside and the Humidity is 82 percent and my roommate is uncomfortable so he opened up the House. I am concerned there could be mold now in the house. Can he cause damage to the house is my question
So more TOTAL humidity in the same given temperature can impair people from releasing heat from the body? So do people living in very high TOTAL humidity climates be prone to get overheated and heat stroke compared to lower total humidity with same temperature? Maybe it is easier to run in low humidity climates because of that
except that in low humidity environment your body will shed more water to cool itself, and you can dehydrate quicker (also affected by altitude)... people who run need to really hydrate a day in advance to be ready for that effect...
And this was how thanks to Bryan Orr I lost my irrational fear to get indroduced in the psychrometrics field a couple of years before with his first podcasts.
Do you have a link to that podcast.
I HATE psychometrics.
Mr Bryan I am learning hvac ! English is my second language! My instructor told me saturation meaning liquid n vapor both exist! Yes that’s true! When I ask him said if I open with refrigerant cylinder to atmosphere it still saturated? He said yes! I don’t get it! For I understand meaning if saturation has to be in seal container! Liquid molecules go up become steam molecules, n steam molecules touch liquid come back to it! Rise molecules n come down molecules number equal! It’s call dynamic equilibrium! That’s real meaning for saturation! Even though water n refrigerant is big difference right! But saturation still meaning the same? how refrigerant be saturate with open pot or open Container? Mr Bryan can u please help me out n explain it please?
Didn't have to care about humidity until I have to care for my piano, which is technically alive?
So if I use a dehumidifier.
A/C will be more efficient in a high humidity area?
Why haven’t someone come up with pulsing the air handler’s heat strips to allow long run times to reduce humidity in the home? The ultimate whole home dehumidifying solution, and no extra unit needed.
Or you could get a variable speed blower with a dehumidification thermostat.
Justin Beaty I do! Trane/Aprilaire.
The Venstar Colortouch T5900 model thermostat has an option to run heat strips while dehumidifying. Only one I’ve seen so far.
Tho it can b tough following these vids r gospel
I was looking for a simple breakdown as if you are explaining this to a 4 year old and instead I got cranial bleeding...
how is water vapour lighter than air?
The molar mass of diatomic nitrogen and diatomic oxygen are both greater than the molar mass of water. Most of air is nitrogen and oxygen... that's why the water molecules float off into the sky and make clouds...
@@lylestavast7652 thank you
✅
#RH
Too much information but less details. Is there a video to learn all what he said in details?
like
Huh
Mr. Carlos, you don't look that clean to me, get a shave Gaborone.