Attention Wrightsoft Users!

  Have you ever completed a load calculation and it just seems like it was short of what you had expected?  Particularly when you are first starting out with a tool, contractors can make mistakes. After all, we tend to learn "the hard way", right?  In an effort to make software work, the companies tend to start with some default values that require adjustment.  For instance, most have the duct system in the conditioned space calculating zero gains or losses.  If the ducts were in the attic, this could be as much as a one ton load that is missed! Internal gains tend to start at zero, and the foreground for windows is something between crushed rock and green grass.  Most contractors find these values, over time and as they gain experience with the program.  One still overlooked setting in Wrightsoft, a feature that no other ACCA approved software employs, is the Rate Swing Multiplier (RSM).  This can cause you to lose as much as 11% of your sensible gains in an otherwise perfect load calculation, maybe more!

Read More

Views: 87

Replies to This Discussion

YES running loads is like rounding up kats.  You very big knobs like south windows, open return in attics, unsealed supply's of building,   I was at a new home 2 yr old  this week - she claims the 1560 sf 4 spit  75,000 BTU/hr 2.5 ton AC is not big to H/C home.  So I just ran a load and come up with 2/3 of that  but when I ran the blower door  a big -50 PA was 3020 CFM  this home did not get sealed between walls where the plumbing comes up.  The HVAC sheet steel installer got the wrap but I feel the low end builder got what he paid for.   Then HVAC contractor  just put in  a 3 ton and 100,000 BTU and now will bid just this over sized "system".

My point is You must test out.     I have used  Wrightsoft for 20+ yr  and I feel it over sizes 10-25% If you do not test out and redo the numbers.   One of my .goals is to beat the 1st load.   To test is find run time when the temp outside is at design temp - I look for 100%  run time with out the heater hitting high limit.    Gramps told me to size to -40  and I use now 0'.    Now you see that  systems get over sized 

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

Tom Mallard replied to Hal Skinner's discussion How much heat energy is lost through the floor of a house?
"For self-heating homes I'm using an insulation board under the joists to be able to use that…"
1 hour ago
Kevin Jordan shared a profile on Facebook
1 hour ago
Profile IconWhitney Cooper and Mike Burton joined allen p tanner's group
Thumbnail

Energy Auditing Equipment for Sale, Trade or to Purchase

Discuss the pros and cons of the equipment you are interested in prior to purchase. Post equipment…See More
1 hour ago
Kurt Shafer posted a discussion

Where can I find the best radiant barrier to install under my roof?

As home energy professionals, we all need to know the best way to prevent attics from overheating…See More
1 hour ago
Kurt Shafer posted a status
"What is the best radiant barrier for my roof built in 2000 in Temecula CA?"
1 hour ago
Profile IconSteve Mohler, Victor Couto, Melvin Calahan and 2 more joined Home Energy Pros
2 hours ago
Aaren Stewart posted a discussion

HVAC - Cooling and Heating Load Reduction

Common load reduction strategies include:      Tightening your building covering and adding…See More
5 hours ago
Kevin Jordan posted a photo
10 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service