Replies

1. 
   Tim | Jul 01, 2009 10:45pm | #1

   pencil, paper, calculator - probably have them all now!

2. 
   BillHartmann | Jul 02, 2009 12:39am | #2

   http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=121553.1

   .
   William the Geezer, the sequel to Billy the Kid - Shoe
3. 
   Clewless1 | Jul 02, 2009 03:07am | #3

   The least cost is zero ... do it by hand manually ... just the way I learned it. Are you doing a house? Are you doing room by room to size ductwork? Or are you simply trying to size the furnace/A/C equipment size? There are some good books, I think that would help. I've always used "Concepts in Thermal Comfort" by Egan ... an old book using old ASHRAE methodology (simplified), but reasonably accurate. It goes from overall heat loss/gain to duct sizing.

1. 
   brownbagg | Jul 02, 2009 03:58am | #4

   go to hvactalk.com, ask them nice guys always willing to help

1. 
   xxPaulCPxx | Jul 02, 2009 06:14am | #5

   Exactly.  Make sure you tell them you are doing it yourself, they really respect that there.

    

   <snort>

    

    

   Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

   Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

2. 
   mencheman | Jul 08, 2009 03:54pm | #9

   Thank you , when I get a chance I will write back and find out more from you , I would rather do it myself , thanks

3. 
   oops | Jul 08, 2009 04:59pm | #10

   Like you, my info is old. The R and U values are out of date. The construction systems and techniques in my books are obsolete. Is there a book out there that you know of and could recommend? Thanks.

1. 
   Clewless1 | Jul 09, 2009 05:03am | #11

   There is really nothing wrong w/ old stuff, really. It's not like R-values have changed much. new materials w/ new R-values, but the calcs are much the same and accuracy reasonable. My book, I bought in college back around 1977 maybe. While they have changed some of the methodologies, the concepts of the calc are really unchanged. The only new things are new U-values (e.g. polyiso and low-e glass). You can calc the net average R-value of a framed wall if you want to be detailed about it or use the two values and estimate a rough ratio of insulation to framing, etc.

   Frankly, I'd generally NOT go to great lengths unless you had a need or special interest in the newer methodologies. You can size ducts and equipment using the old techniques. Just make adjustments for the new knowledge (e.g. air leakage rates, glazing, etc.).

4. 
   systembuilder | Jul 02, 2009 05:22pm | #6

   I own HVAC-Calc. Around $400 but homeowner (1 home) version for around $50.

   I am just starting to use it so can't yet give thumbs up or down.

   Dan

1. 
   plate | Jul 02, 2009 05:28pm | #7

   I have used HVAC calc and I think its great at $50.  It will calculate all the loads but it will also give you room by room duct sizes allow you to feed the room with several ducts and it will  recalculate the duct sizes. 

1. 
   brownbagg | Jul 02, 2009 06:46pm | #8

   our power company will do it free.

5. 
   GaryGary | Jul 09, 2009 05:12am | #12

   Hi,
   If you just want to do a home heat loss, you can use my free one:
   http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

   Gary

1. 
   mencheman | Jul 09, 2009 02:27pm | #13

   Gary , Thank you , Back to you later