Hi Chris , i got a question about manual j , how apply 1800 sqft into table 7D AE BASE CASE LATENT GAIN if square feet goin in 500 , chart 1000-1500-2000-2500-3000 max
Hello Sir, I have confusion while doing the load calculation for the Unfinished and finished basements about when to include them in the calculation. Please answer.
Hi Chris. Thank you so much for all this excellent information. I'm having a very hard time finding anyone explain how to input vaulted ceilings into the various manual J software. Is it as simple as figuring out the equivalent air volume as if the ceiling was flat and inputting that calculated ceiling height? And then inputting the actual ceiling square footage which will be greater than the floor square footage? Also, is there a better way on placement of registers on such ceilings - like one at the very top and one lower closer to the wall, rather than just having one at the lower location? If you could help by sharing your thoughts, that would be so helpful and appreciated.
Hi @a.t.701, thanks for watching! Vaulted ceilings are typically entered into Manual J software as a 'roof/ceiling combination' or a Mansard (if you have a small flat ceiling at the peak). The room height should always be the wall height, and anything above that for volume is added to the ceiling input. The location of supply registers can depend on the application, like a room evenly heats better if on a floor, or more even cooling if in a ceiling. If you have a ducted system that operates heating and cooling, then one will have to be sacrificed - which is usually the season with less run time. So, this is one of the reasons we see a lot of floor registers in New England. I hope this helps!
Semper Fi brother. Just found you. I am a RNC installer looking to move into design and layout. I can appreciate your attention to detail when it comes to correct installation and following code. Would appreciate any help in making my work better, making my installers better and making customers happy.
Semper Fi Greg! If you are ok with reading, I provide a ton of content for free on my website: hvacproblog.com If you want more structured, video training (at a cost), you can find options on my Patreon! What would you say is your #1 need when it comes to learning a detail with System Design?
I Hate to sound profoundly ignorant, but I’ve heard from a couple guys that have their Michigan mechanical license say it’s either suggested or some sort of standard procedure to add 20% to the calc. That true, false or it’s more complicated?
A bit more complicated. Most Manual J v8 software has about 20% oversizing already built in due to rounding, etc. Also, if you are installing an A/C or Heat Pump, there is an allowable oversizing as part of Manual S equipment selection. However, you should not simply 'add 20%' as you can see this will continue to significantly oversize the system...
Great Job Chris! Loved the seminar. This information was incredibly useful. I love using these videos as a supplement in my classroom instruction. Thanks man! Hope you're doing well?
We have an old Farm house completely gutted ready for HVAC. I have been asking HVAC companies if they do load calcs and most don't. The last one I asked if they would do a Manual J and they said yes. I asked how they could do an accurate Manual J before spray foam and Aero-Barrier and he said they use an estimate method. Sounds a whole lot like Manual E to me... Can you complete a Manual J before insulation and air seal?
My house is 2500 square ft. The size of my air conditioning unit is 3 1/2 ton. The house was built in 1988. I don’t consider 75 to be cool. What size unit do I need to be able to stay at 70 when its 95 outside.
So so so many variables here to even answer the question. Is that 2500 above grade or total, if you have a basement? How much of your house faces south? What size furnace blower fan in CFM? Was the AC new in 1998? Any chance you could track down the Make and model of the indoor and outdoor units that you currently have? Have you installed any upgraded windows or insulation since you bought it new? What part of the country do you live in? if high humidity, do you have a dehumidifier? Theoretically, 3.5 tons should easily be able to offset and take off 25 degrees of heat off the supply air on a standard system especially if you have enough return air. Do you change your filter and use the correct MERV rated filter for your system often? Conventional thinking states that a 4.5 tons of cooling is needed based on a 500cfm per ton. There are way more questions, but i could get pretty close with a lot of the items listed above. I have seen tight houses that could do it it with 3 tons and super loose homes that would need 5-tons of cooling with a dehumidifier to pull enough heat off. Do you have your equipment cleaned yearly like the AC coil and outdoor condenser unit?
cool calc always seems WWWWAAAAYYYYY off. just did one block and room by room for the same new construction house. got different numbers for each. Just less than 20kbtuh for cooling and 49.5kbtuh for heating block, and a total of 28.8kbtuh for cooling and 39.7kbtuh for heating room by room. If all the info I'm putting in to any software is a guess (new construction), it seems like taking rule of thumb guess would be just as (in)accurate. WTF over. Super frustrating, buy all the programs, use the free ones, do the training and watch the videos. Its all a freaking guess!!!
I’m enjoyed in this informative lecture Chris. I’m graduate from hvacr school so what’s manual you’re advice me to go with it? I want to start in residential work. Thanks.
Thanks and I want to ask you about where to get these books for me to continue learning all about it if you can send me the information about it thank you again 😊
Hi Balfret! Thanks for commenting and asking - the best place to purchase the ACCA Design Manuals are on their website: www.acca.org/standards/technical-manuals
Hi George! Copies of my presentations are made available to my Patreon Members only at this time. If you are interested in learning more, or using them as a resource, I have Manual J, S, & D Training available as part of the Elite Membership, with downloadable PDF copies...www.patreon.com/HVACProBlog?fan_landing=true
Well done Chris. Just getting through the final steps of starting an LLC. Had some schooling and mostly commercial service experience (little bit of construction experience). Wanna run this business right and not sq ft / ton method. Thanks for putting this out there.
Hi Frank! Great question! The Site Survey Form is available on my Patreon Site as a PDF resource, in lieu of in-person trainings since the pandemic restrictions in New England: www.patreon.com/HVACProBlog?fan_landing=true Chris Morin is the Author, Owner & Founder of the popular HVAC Pro Blog. For Advice with Residential HVAC System Design, Quality Installation, and System Diagnosis, you can find Chris’ Articles on HVACProBlog.com, Exclusive Member Content on Patreon, or popular social media outlets Facebook, LinkedIn, Twitter and TH-cam.
Well done! Well presented. Doing master suite/garage addition extreme north California. Im old school extensive engring background started w autocad R12 in high school, hell, backed into a C10 license working in telecom - really having my eyes opened. 14 sheets of design plans I drafted, thought I was going to impress the guys down at the county for my little addition project- hah! Title 24 ... Wha? Manual J? errrr... Sprinklers? INSIDE the house?? Just thnkn where does it end? we will be counting and accounting for and taxed on, sheets used in the bathroom next. Great job here though, I will be aware of and able to do the load calcs based on your vids. But when the code/gov is telling you when you are comfortable, how bright your lights can be, how many gallons you can flush, and what equipment you can put in your own house..? Its a free country? not so much... Shweew, I feel better, lol. Great job, thank you for your service.
Good information- thanks for sharing this. The load is constantly changing throughout the day so variable speed is the key.
This is really excellent, thanks so much for doing this. Learned a ton (no pun intended)
Great information, thanks for the tip on CoolCalc to do calculations.
Awesome presentation! Thank you.
Hi Chris , i got a question about manual j , how apply 1800 sqft into table 7D AE BASE CASE LATENT GAIN if square feet goin in 500 , chart 1000-1500-2000-2500-3000 max
Thank you for this video interested in your guide and and advice on studying for the hvac license exam
Hello Sir,
I have confusion while doing the load calculation for the Unfinished and finished basements about when to include them in the calculation. Please answer.
Hi Chris. Thank you so much for all this excellent information. I'm having a very hard time finding anyone explain how to input vaulted ceilings into the various manual J software. Is it as simple as figuring out the equivalent air volume as if the ceiling was flat and inputting that calculated ceiling height? And then inputting the actual ceiling square footage which will be greater than the floor square footage? Also, is there a better way on placement of registers on such ceilings - like one at the very top and one lower closer to the wall, rather than just having one at the lower location? If you could help by sharing your thoughts, that would be so helpful and appreciated.
Hi @a.t.701, thanks for watching! Vaulted ceilings are typically entered into Manual J software as a 'roof/ceiling combination' or a Mansard (if you have a small flat ceiling at the peak). The room height should always be the wall height, and anything above that for volume is added to the ceiling input.
The location of supply registers can depend on the application, like a room evenly heats better if on a floor, or more even cooling if in a ceiling. If you have a ducted system that operates heating and cooling, then one will have to be sacrificed - which is usually the season with less run time. So, this is one of the reasons we see a lot of floor registers in New England.
I hope this helps!
Semper Fi brother. Just found you. I am a RNC installer looking to move into design and layout. I can appreciate your attention to detail when it comes to correct installation and following code. Would appreciate any help in making my work better, making my installers better and making customers happy.
Semper Fi Greg! If you are ok with reading, I provide a ton of content for free on my website: hvacproblog.com
If you want more structured, video training (at a cost), you can find options on my Patreon!
What would you say is your #1 need when it comes to learning a detail with System Design?
Hello Chris, I just emailed you. Hope to hear from you. Great video!
I am happy to help and will get back to you as soon as I can!
I Hate to sound profoundly ignorant, but I’ve heard from a couple guys that have their Michigan mechanical license say it’s either suggested or some sort of standard procedure to add 20% to the calc.
That true, false or it’s more complicated?
A bit more complicated. Most Manual J v8 software has about 20% oversizing already built in due to rounding, etc. Also, if you are installing an A/C or Heat Pump, there is an allowable oversizing as part of Manual S equipment selection. However, you should not simply 'add 20%' as you can see this will continue to significantly oversize the system...
Great Job Chris! Loved the seminar. This information was incredibly useful. I love using these videos as a supplement in my classroom instruction. Thanks man! Hope you're doing well?
Thanks Derek! Things are great! Glad to hear you are still able to use the content…
What the best software load calculation, for you?
We have an old Farm house completely gutted ready for HVAC. I have been asking HVAC companies if they do load calcs and most don't. The last one I asked if they would do a Manual J and they said yes. I asked how they could do an accurate Manual J before spray foam and Aero-Barrier and he said they use an estimate method. Sounds a whole lot like Manual E to me...
Can you complete a Manual J before insulation and air seal?
Would like to have the free resource
My house is 2500 square ft. The size of my air conditioning unit is 3 1/2 ton. The house was built in 1988. I don’t consider 75 to be cool. What size unit do I need to be able to stay at 70 when its 95 outside.
So so so many variables here to even answer the question. Is that 2500 above grade or total, if you have a basement? How much of your house faces south? What size furnace blower fan in CFM? Was the AC new in 1998? Any chance you could track down the Make and model of the indoor and outdoor units that you currently have? Have you installed any upgraded windows or insulation since you bought it new? What part of the country do you live in? if high humidity, do you have a dehumidifier? Theoretically, 3.5 tons should easily be able to offset and take off 25 degrees of heat off the supply air on a standard system especially if you have enough return air. Do you change your filter and use the correct MERV rated filter for your system often? Conventional thinking states that a 4.5 tons of cooling is needed based on a 500cfm per ton. There are way more questions, but i could get pretty close with a lot of the items listed above. I have seen tight houses that could do it it with 3 tons and super loose homes that would need 5-tons of cooling with a dehumidifier to pull enough heat off. Do you have your equipment cleaned yearly like the AC coil and outdoor condenser unit?
cool calc always seems WWWWAAAAYYYYY off. just did one block and room by room for the same new construction house. got different numbers for each. Just less than 20kbtuh for cooling and 49.5kbtuh for heating block, and a total of 28.8kbtuh for cooling and 39.7kbtuh for heating room by room. If all the info I'm putting in to any software is a guess (new construction), it seems like taking rule of thumb guess would be just as (in)accurate. WTF over. Super frustrating, buy all the programs, use the free ones, do the training and watch the videos. Its all a freaking guess!!!
I’m enjoyed in this informative lecture Chris. I’m graduate from hvacr school so what’s manual you’re advice me to go with it? I want to start in residential work. Thanks.
Where to purchase the software? Thanks!
USMC Veteran!!
Thanks and I want to ask you about where to get these books for me to continue learning all about it if you can send me the information about it thank you again 😊
Hi Balfret! Thanks for commenting and asking - the best place to purchase the ACCA Design Manuals are on their website: www.acca.org/standards/technical-manuals
How do I get a copy of your PowerPoint presentation.
Hi George! Copies of my presentations are made available to my Patreon Members only at this time. If you are interested in learning more, or using them as a resource, I have Manual J, S, & D Training available as part of the Elite Membership, with downloadable PDF copies...www.patreon.com/HVACProBlog?fan_landing=true
Well done Chris. Just getting through the final steps of starting an LLC. Had some schooling and mostly commercial service experience (little bit of construction experience). Wanna run this business right and not sq ft / ton method. Thanks for putting this out there.
Thanks for the kind words James! Looking forward to hearing your success in the near future!
MWSS 271, Cherry Point!
Nice! I was with MASS-1 when we deployed for the Iraq Invasion in 2003! Semper Fi !
Where can I find your site survey sheet?
Hi Frank! Great question! The Site Survey Form is available on my Patreon Site as a PDF resource, in lieu of in-person trainings since the pandemic restrictions in New England: www.patreon.com/HVACProBlog?fan_landing=true
Chris Morin is the Author, Owner & Founder of the popular HVAC Pro Blog. For Advice with Residential HVAC System Design, Quality Installation, and System Diagnosis, you can find Chris’ Articles on HVACProBlog.com, Exclusive Member Content on Patreon, or popular social media outlets Facebook, LinkedIn, Twitter and TH-cam.
Well done! Well presented. Doing master suite/garage addition extreme north California. Im old school extensive engring background started w autocad R12 in high school, hell, backed into a C10 license working in telecom - really having my eyes opened. 14 sheets of design plans I drafted, thought I was going to impress the guys down at the county for my little addition project- hah! Title 24 ... Wha? Manual J? errrr... Sprinklers? INSIDE the house?? Just thnkn where does it end? we will be counting and accounting for and taxed on, sheets used in the bathroom next. Great job here though, I will be aware of and able to do the load calcs based on your vids. But when the code/gov is telling you when you are comfortable, how bright your lights can be, how many gallons you can flush, and what equipment you can put in your own house..? Its a free country? not so much... Shweew, I feel better, lol. Great job, thank you for your service.
Thanks for the kind words Trent! Happy to hear this helped...
New to me
👌