Could anyone help me calculate a breakdown that shows  heat loss in BTU/hour that adds up to 100% and shows % or subtotals for the sub-categories that add up to 100% based on  u values and Area for the sub-categories I guess per square foot of area in question. For a stated day with stated temperature inside of 70 degrees and outside temperature of 40.
The areas in questions are: 
 
-Ceiling. with an R4 value of insulation
-1st Floor to unconditioned basement 2x8 empty cavity, 3/4 pine groove plus 1/2 hardwood -No insulation
-Windows/Glass casement windows double pan glass
-Exterior Walls with 3/4 pine siding, 3/4 insulation, 1/2 drywall
-Air change
I would be grateful for any advice you guys could provide!
Thanks 

Views: 279

Reply to This

Replies to This Discussion

Answer equals = U * A * T

As you are missing A or area.... for the first one

What the Delta T & A is for the second

What the U value & A are for the third & fourth...

Your question asked is impossible to answer - you fill in the blanks & you have your answers

I was thinking that in order to stay away from a full blown home calculation, I would keep it simple so I could learn the concepts. I suggested a one square foot of the material, temperatures ranges are 40 outside to 70 inside. 

Knowing the area (one square foot) and knowing the temperature range... Can I figure the rest?

Thanks

Hi Luis,

It gets a lot more complicated than what you are asking for, but learning is something a lot of people should be doing. 

Your one ft² example will give you an idea as to the heat loss per foot in one hour, but only for the given temperature.  If you want the loss per year, you add in the heating degree days.

Sean's equation Q = U x A x ▲T gives you the btu's for the area and the u-value specified.

If you want to estimate the energy lost for a year, use: Q = U x A x HDD x 24.

If you want to play with a very basic heat loss calculator, try Gary's over at build it solar:

http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLos...

Bud

RSS

Videos

  • Add Videos
  • View All

Twitter

Latest Activity

Ed Voytovich replied to Beverly Lerch's discussion Fireplace drafts
"Our solution was to install a Lopi Answer wood burning insert that vents directly through a metal…"
38 minutes ago
kevin mack is now a member of Home Energy Pros
3 hours ago
Jim Gunshinan's blog post was featured

A Healthy Home and a Healthy Bottom Line

There has been a lot of interest of late in the weatherization and broader home performance…See More
22 hours ago
Jonathan Beers commented on Home Energy Magazine's blog post Natural Gas is Becoming Less Attractive
"The carbon intensity of electricity use (lbs. of CO2/MWh) varies a lot from region to region. For…"
23 hours ago
Diane Chojnowski posted events
yesterday
Home Energy Magazine posted a blog post

Natural Gas is Becoming Less Attractive

The United States and Canada have been fortunate to have access to natural gas for space heating,…See More
yesterday
Jim Gunshinan posted a blog post

A Healthy Home and a Healthy Bottom Line

There has been a lot of interest of late in the weatherization and broader home performance…See More
yesterday
Luke Langhals commented on Tom White's video
Thumbnail

Passivhaus Goes Personal

"Great video. This shows that Passive House isn't all about Energy. Selling it to customers…"
yesterday

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service