Great comparison ! What about a vented attic without any insulation whatsoever and a vented attic with Insulation between the rafters + vent www.energystar.gov/saveathome/seal_insulate/do-it-yourself-guide/about-attic-ventilation (link recommended by Energy start)

👍 M.A.D air!!!!!! No return path for air when room door is closed! Casing room pressure problem!

In Colorado, we are typically low humidity, and most HVAC systems are installed in the basement. My issue is that we have bathroom exhaust fans and kitchen exhaust fan for a gas stove, which are temporary, but combined run for hours everyday. We also have gas hot water heater, and a gas furnace which draw in outside air through two fresh air intakes which dump into the basement. Then you add in a radon gas evacuation pump, and it’s safe to assume that our homes are under negative pressure. This makes me wonder if we should be adding an intake fan and heat exchanger to the fresh air intakes to control the location and conditions of the the air penetration and cause positive pressure.

Thank you for creating this video for those of us who don't work in the HVAC industry. Doing a search pulls up a ton of videos on Manual J calculation training videos, but nothing high level with a simple explanation like this video!

That means there is a ghost in ur home 💀

great video. i live in a condo 2BD 2BA approximately 1000sqft and it has it's own HVAC system (inside my unit), washer and dryer hooked up to some duct by entrance door, kitchen range fan, bathroom fan, 3 windows that open for each room (master bedroom, living room, and spare room), along with a patio door opposite of the main entrance. Because we are the 3rd floor out of 4 floors, i would assume the washer and dryer duct is centralized but i do believe our HVAC is internal and no other ducting to and from other floors or at least from what I've gathered. I currently have negative air pressure utilizing your method of closing everything and opening the main entry door a crack, which determined air coming in and not out. How do i create positive air pressure within this environment?? Forgot to mention, because it's a condo, my front door is within a corridor with doors on opposing ends that open to outside air. Also, thanks for your time!

Thank you for your hard work

Would house humidity go up if you increase positive or negative house pressure? Our humidity went up when we increased size of our return duct and we don’t know why. We think we have negative pressure but when barometric pressure drops in evening humidity goes down we are perplexed

I’d like to buy your pens, but the link doesn’t seem to work.

With foam backed roof sheathing regular roofing shingles have a reduced lifespan. Metal roofing is preferred and the foam acts as a sound reducer as long as it is closed cell to prevent sound or water vapor migration

If I purchased a 20-year-old house, how can I tell what type of windows it has?

Question: I have a newer constructed house and I noticed that I get headaches when the heat is on only in the master bedroom. Sometimes the pressure closes the door. All bedrooms are on the second floor. So the master is on one side of the house, the remaining 3 are on the other side. Fyi...the other rooms are always colder than the master room. Does that mean it is a negative pressure and the exaust setup is incorrect?

So, everyone has negative pressure pulling in outside air (from the fireplace in my case) when an exhaust fan is turned on. Do you have a solution? I had to seal up the house to pass the air test done by the county. Now the exhaust fans pull from the flu in the fireplace (I don't close it because we have fires all the time). I open a window when the dryer is on but want to know if you have a better solution.

I saw hygienic flexible aluminum ducting which had double of standard flexible ducting prices. Do you recommend this for homes? Or are they only feasible for hospitals etc?

How hot is the pressurized gas refrigerant ? if it depends, assume a 1 ton AC

Found your video to be very educational. I came here is seeking an answer as to why the vents on left side of my house are displacing cold air from the vents when the furnace is off. It is 2 degrees or more colder on this side of the house (office). When the room is heated, the office feels cold after the furnace goes off in 4-5 minutes, or sooner, depending on how cold it is outside. I suspect the warm left over air in the cold vent is mixing. This is resulting in cool air dropping down from the vent which requires I wear a jacket and my fingers and hands are cold, although the thermostat says it is 71 and a local temperature gouge in my office saying it is 69. I tried your negative test and I even more confused. Yes, when opening the door on the left side of the house, cold air came through the crack of the door. However, when I slightly opened the door on the right side of the house, which feels warmer and more comfortable, the air flow was double, if not triple, the amount of cold air coming through the door crack. I will say the stairs to the 2nd floor are just beyond the right front door, so I suppose the argument it is sucking cold air in and going straight upstairs. However, the 2nd floor is very comfortable and warm at 71 degrees. Either way, both doors indicate I have negative pressure. I believe strongly the house HVAC ducts were installed poorly (looks like spaghetti and you cannot even get to ducts to check), they are not sized correctly with 10ft ceilings and very little air flow out of the vents such that a 6ft person standing directly under the vent cannot even feel the heat hitting their head when the furnace is on. No luck with HVAC companies as they are looking for easy fixes (replace heating unit with larger system, move system from 3rd floor to crawl space, etc.). I am not sure they are schooled in how to address negative pressure homes. Not sure where to go from here.

Jaguar Heating and Air - Sacramento, California I wanted to bring up about this company: they are so shady for taking peoples money without following up the installation. They dont return phone calls from the sales person or co-owners. The will sell you something like a water heater and Jaguar does NOT have a plumbing license. They will take your money and run with it and your stick you with the problems. They will also make holes in your walls without the consent of the homeowner and NOT written on the contract. Beware with some of the sales person who pretend to be car salesman, cause that is what they are "car salesmen" They have sold a "water heater" to a clients and wanted it. They the customers ask for it, if Jaguar does install water heaters in which they pulled a "lie" up their sleeve and said "yes" that they can do it, but Jaguar knew that they didnt have a "plumbing license C-36 Classification" but sold it anyways, cause they were afraid that they would lose the sale for installing a water heater. Jaguar Heating went ahead installed a "water heater" and installed it on the property, but did an inspection for the HVAC and wrote change out 5-ton split unit (WATER HEATER NOT INCLUDED) so that they get the permit for the HVAC and hire somebody with a plumbing license to get the "water heater" permit for Jaguar to do their dirty work all because dishonesty and money and leave the client behind. This company will anything to keep their good reviews and "throw out" their bad reviews, so that they can get you to be suckered in doing business with them. Beware they have a way with words in selling you something that your not getting, especially coming from a sales person. Here is the problem with contractor they take short cuts on everything that they do, so that can shaft you and they are so called "shysters". This company has installed 2 water heaters without a plumbing license and continue to cut corners or continue to lie to customers just to take their money and leave them with the problem. When a water heater is installed without a plumbing license here are the consequence below to inspect: 1: Who is going to keep up the service call and repair for the next 10 years for the warranty 2: Who is going to do the repair service if it starts to leak water all over the garage in case there is water damage, plus the clean-up aferward. 3: The homeowner insurance "will not" cover repairs if the company installed it without a license (the homeowner insurance will send an "estimate adjuster" and will investigate to see if the company had a Plumbing License during the installation, "if not" they (the homeowner insurance) will cover the repairs 4. Plus, who is going to pull the "permit" if the company didnt have a Plumbing License, now the company will get a 3rd party who has a license will get the permit, but its NOT a good idea, because they dont want to get involved in touching somebody's else work and get their hands dirty as they say. For example, mechanic will NOT touch car if its still under warranty through the manufacture, cause it will VOID the warranty. 5: Most Real Estate and Buyer "will not" buy a home if the house doesnt have permits cause the buyers homeowners insurance will NOT cover it, cause the installation was done "without" license. They way they will if the seller scraps the installation and "redo" the installation and get someone with the Contractor License for the job Since I know this how the laws work, dont get stuck with some crappy sales person....."the old saying goes: "If it sounds too good to be true, then it probably is" referring to? Is there any truth to this statement? Why might something sound too good to be true? Word to the wise and good advise: if your not sure about a Contractor License then do this to see if legit 1: Go to Contractor License Board and get or ask for their license so that you know if they have an active license and they are selling exactly that fits their license discription 2: Make sure you to the BBB: Better Business Bureau cause they have reviews that are true legit, cause review can and cannot be taken off because the reviews will stick and BBB is owned by the State and Federal Regulations. 3: Dont read "yelp or google" cause they have friends and relatives and will creat 20 to 50 username account and they are not true only family review supported Does all makes sense....dont get shafted and or played

Hello, just watched your video and found it to be super informative and interesting. Just bought a house built in 1990 it has a 4 ton Ac and heating unit all in one. Located on the roof. I installed a one piece dog door that mounts on to the tracks of my sliding glass door. And when the air conditioner comes on the flap of the dog door pushes out and stays open. Is this what your calling a positive air flow? And what do you recommend I do to decrease this air flow so the flap stops blowing out and sending all that cool air outside? Help !! Please!!

Your videos are great and I have concern about what my HVAC company is wanting to do while installing a new system. They are wanting to run a dehumidifier with the intake, pulling air from outside that is filtered and dumping it into the Plenum before the filter. This is to get fresh air into the house and also create a positive pressure. 1 live in south Louisiana and pulling air without the dehumidifier would be putting 90% humidity into the Plenum. Your advice is greatly appreciated.

Can you do a video on the positive and negative effects of totally closing a grill off?

This was a super interesting video. I live in South Florida and the heat has been brutal on the AC it is not feeling great at the peak of the day. If we have a 95 degree day it's going to be a bad day inside but it it drops to 92 to 93 its a world of difference. Thanks for the video your explanations were spot on I plan on sharing this video and I want an energy inspection.

Do you add the attic in the square footage

Thanks for the vid! Where can I find those portable thermometer/hygrometer table units you suggested? The store link doesn’t work.

By chance I just discovered a very dangerous negative pressure condition in my home. Hot and humid weather this past week so we closed all windows and doors, ran 2 portable air conditioners venting to the outside. Add an electric dryer that runs a lot....etc etc Today I cleaned my oil boiler and thanks to some left over crud when I fired it back up I saw smoke entering the room through the closed damper. No big deal right. I just missed vacuuming some dirt in the fire chamber. The next time the boiler fired it did the same thing. The damper was never pulled open while the boiler was firing. I pushed it open to make sure it wasn't stuck and it immediately closed back up. I opened a window to help exhaust the smoke and a wind hit me in the face. There was no wind outside but the negative pressure pulled so much air in the window you swore it was windy outside. I opened a second window and the same thing. I left the windows open and observed the boiler the next time it fired and the damper opened and no smoke or smell entered the room. I will be adding some sort of ventilation in the mechanical room soon. Thanks for the videos!

We finished out our attic and just ran new ducts. Since then our master bedroom has been getting warm. Walking out of our bedroom you can feel actual conditioned air. I am thinking we screwed up so contacted hvac company. They said possible negative pressure, and offered the only solution of adding return in my finished attic. I kept the door open for days and it never solved the problem.

I am mechanical engineer finding job in HVAC field there, plz guide me

Hii

That looks great and fast ! Do you guys have courses to teach such skills ?

Anyway you can show exactly how to use auto cad with wrightsoft?

You guys are amazing

Great explanation!

Educational!!!

🤓

Interesting video! Would a local air conditioning unit (not central ducts) that is taking air from just that room and spitting it back into that room, create positive pressure for that room?

It would have been nice if you talked more about the different methods of cleaning ducts that companies use rather than just listing one method. What about the giant vacuums? What about the whip on the end rather than the brush? Is there a way to clean flex duct that is less likely to damage it? There were so many things I wish were talked about in this video.

More than cleaning the coil and blower the insides of the furnace and evap will often be very dirty.

Did you recommend having two separate filters, one at the grille and one at the air handler? That's not a good idea, I don't care how low your static pressure is.

Do you know where is the best to place supply and return register in basement rooms for heating? Also in what direction should supply register should blow hot air?

Finally someone from this county is saying we over size systems in this area. I just removed a 4 ton unit from 1400 sq ft home. Put in a 2.5 ton guy loves it!

Thank you for sharing your knowledge

I like what you are saying. And I know all of it is important. But what happens if you install a system. Then the homeowner paints their White House to Dark green. They cut down the tree that used to shade their house? Do you think sealing a crawlspace can change the AC properties tremendously?

I like what you are saying and I TRY to get units as close as possible but One question is if the color of the house, the shade of the house, and the lay out of the house is important. (And I know they are and can change the outcome of the way the system works, just like keeping a door open or closed can change the CFMs and airflow of a room.). What happens when that tree gets cut down and they paint their White House dark green? Worse yet. They foam seal their attic and seal their crawlspace?? Does sealing a crawlspace alone affect the AC tremendously?

Good video to show clients for my home performance jobs