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: 281

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

Latest Activity

Charles Cormany added a discussion to the group Job Board
Thumbnail

Energy Efficiency Incentive Program Manager - Efficiency First California (Berkeley)

Position Title: Program Manager Terms: Full time, available immediatelyAbout Efficiency First…See More
4 hours ago
Charles Cormany joined Diane Chojnowski's group
Thumbnail

Job Board

This group is for posting jobs related to all aspects of the home performance industry including…See More
4 hours ago
Linda Wigington liked Home Energy Magazine's blog post Art Rosenfeld's Legacy
6 hours ago
Ellen Phillips Soroka is now a member of Home Energy Pros
6 hours ago
terry nordbye added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase
Thumbnail

Combustion anaylizer Testo 310

This little beauty only has a few hours on it. Almost brand new in box.Sell: $350.Terry 415 669…See More
10 hours ago
Barbara Smith's video was featured

Indiana HCA...On Location - Celebrating 40 Years of the Weatherization Assistance Program (WAP)

The Indiana Housing and Community Development Authority (IHCDA) interviewed two clients of Weatherization Assistance Program (WAP). Both homes were weatheriz...
11 hours ago
Home Energy Magazine's blog post was featured
yesterday
Profile IconEfficiency First California and Kevin Daly joined Home Energy Pros
yesterday

Home Energy Pros

Welcome to Home Energy Pros – the unique digital community by and for those who work in the home energy performance arena.

Home Energy Pros was founded by the developers of Home Energy Saver Pro (supported by the U.S. Department of Energy) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network. Please honor our Guidelines

© 2017   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service