Manual J calc inputs and outputs and sizing
I recently found your website and absolutely love the sound advice that is given here.
I am in the process of switching my AC and heating system at home, from oil and window units to a mini split heat pump multi zone system.
My house was constructed in 1970 by the previous owner, so I don’t have a lot of the specifics. It is a single story rancher, with a full unfinished basement that is used for exercise equipment and work bench and tool area. It is located in Southern NJ.
Howerever, I have put alot of time into trying to do the Manual J calculations which I have just somewhat completed.
I drilled a few small holes in my walls to check for insulation. It appears to be full depth, so I am assuming it is R11. When starting the Manual J, it asked about the level of bei g airtight, I choose average but not sure if I should change that to Leaky or in between based on the standards of construction in 1970. The only other real concern I have regarding the inputs is how to ac out for window awnings. It list a box for external shading with a default 1.0 in there but no explication or choices. I am not really sure if that is where it would go. I am thinking to add more insulation to my attic and will run change that in the software and see how that changes the load.
Anyway, my house has 2,782 between the 1st floor and the basement. The basement does not require too much conditioning, mainly too add a little heat in the winter and a little dehumidification in the summer.
The results of the draft load calculations thus far is stating total heating 46,278 btu/hr, total sensible 22,507 btu/hr and total latent 3,745 btu/hr. Does that sound even close to being right based on the year of my house, etc.? Also, how is the equipment sized based on the far apart heating and cooling loads? I can post a copy of one of the reports if needed.
Any opinions and advice would be greatly appreciated.
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