Hello to everyone again -- This is an update on a building I'm working on for a NG furnace.  It's been about a month (a very busy month) since I last posted questions and I have been to the building -- I have some answers and another question about reading LOAD CALCULATIONS. 

The 2052 sq. ft. building has only 1.5" insulated garage door panels for the ceiling as the only insulation (in the attic floor along with 2 part foam on the perimeter walls averaging 2.5" to 4" thick) so I'm looking at blowing cellulose to a depth of 1' in the attic after some air-sealing to bring the heating loss down.  The blower door number was 6275 CFM@50 -- there is a construction flaw where 2 part foam applied to the perimeter's stud bays didn't completely reach up behind a top 2 x 6 band joist (is that what it's called if it's at the ceiling and not at floor level?)  Most bays are pulling air during the BD test.  Also the ceiling garage door panel joints are not caulked.  So I'm hoping to bring the CFM down to some reasonable level by caulking the cracks and using bagged inso stuffed into the stud bays.

I found an HVAC company that gets load calc's done and they gave a bid for a Bryant preferred two stage and ductwork installed inside the envelope (ceiling is 9'3").  They're sizing it at 100,000 BTUs.  

They did two load calc's -- one with minimal insulation (present situation) and one if 1' of cellulose is installed in 2052 sq. ft. of attic floor.

This is the first time I've read/seen an actual load calc so I have a question -- (the HVAC co. has a call into the guy in another city who did the calc and I'm still waiting for his answer) --- The software is "Elite RHVAC Residential HVAC Loads" and approved Manual J and Manual D -- 8th Edition, Version 2

On the first page, the "Project Report" down in the "Check Figures" section the number for square foot room area is correct at 2052 --- the "Volume (ft cubed) of Cond. Space" concerns me.  I would get this number by taking the sq. ft of 2052 and multiplying it by the ceiling height of 9.25' (9'3") for a total of  18,981 cu. ft --- The reports however had two different numbers -- minimal insulation calc being 32,832 and the insualtion added calc's number being 20,520.

Can anybody who knows this software tell me why these numbers are not the basic length x width x height number?

Is there a place on this report where I can see whether they considered all the ductwork is run inside the envelope not up in the attic?

And I don't see where the Blower Door number was addressed at all -- or isn't this the type of calc that uses the BD number?

According to both load calc's (minimal insulation) and ($2,000 more insulation added) I need a 100,000 BTU furnace.

Well -- thanks to everybody in advance for input.

Views: 670

Replies to This Discussion

Thanks for the input -- I don't mind getting training if I could justify it with business income in my area.  I jsut have to do some more research on this.

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

R Higgins replied to William Fisher's discussion Can tankless water heaters provide hot water even when the groundwater is fairly cold?
"I have that problem, 45 to 50 degree ground water, in summer, not that we have much of a…"
8 hours ago
R Higgins replied to Larry Schaffert's discussion How to correctly insulate exterior wall in a 1900 house?
"I'd suggest trying to replicate the existing conditions as much as possible in your rebuild,…"
9 hours ago
Bryan Pringle replied to Bryan Pringle's discussion Dense packed cellulose in basement?
"I am getting a lot of "bad idea" push back on this.  I fully understand that…"
20 hours ago
Greg Mitchell commented on Larry Ralph Jr's blog post Top 7 Worst Crawl Space Repairs
"Spray Foam should be used in crawlspaces.   To learn about closed cell foam in crawlspaces…"
21 hours ago
Jerry Lawrence posted events
yesterday
Morgan M Audetat replied to Bryan Pringle's discussion Dense packed cellulose in basement?
"Right you are. You have to ask: what will the cellulose contribute.  Here in Minneapolis we…"
yesterday
Morgan M Audetat replied to Tony Hicks's discussion Slab-on-grade Insulation
"All slabs float. We have been installing radiant floors on various slab constructions since the…"
yesterday
Tony Hicks replied to Tony Hicks's discussion Slab-on-grade Insulation
"2" XPS foam. I'd love an R-20. Having foam thick enough to get an R-20 would be…"
yesterday

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service