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: 256

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

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.  Home Energy Pros is sponsored by the Better Buildings Residential Network.

Latest Activity

John Nicholas commented on Jamie Press's blog post How to Choose the Right Solar Panels
"How much power do you need?  The looking up appliances and electronics usage, assigning time…"
5 hours ago
Rick Karg replied to Carly@AirCycler's discussion The (Small) Cost of Ventilation Without Recovery
"As a member of the ASHRAE 62.2 committee (and president of Residential Energy Dynamics, the author…"
Friday
Bradford E. White replied to Elizabeth Guinn's discussion ERV in need of backflow preventer.
"I would use an in-line backdraft damper such as Artis Industries or the ones made by Fantech and…"
Thursday
Kim Tanner posted a video

Wireless Air Leakage Testing

This webinar will discuss the use of WiFi technology to conduct and document blower door and duct leakage tests for compliance with local energy codes. The s...
Thursday
Profile IconPerry Grossman, Daniel Pate and Ottawa Furnace Filters joined Home Energy Pros
Thursday
Kirsten Richnavsky added a discussion to the group Building Performance Institute (BPI)
Thumbnail

Breaking the link between unhealthy homes and unhealthy kids

Listen in on IAQ Radio to a discussion on reducing the household triggers that cause asthmaattacks…See More
Thursday
Kirsten Richnavsky posted a discussion

Breaking the link between unhealthy homes and unhealthy kids

Listen in on IAQ Radio to a discussion on reducing the household triggers that cause asthmaattacks…See More
Thursday
Kim Tanner posted events
Thursday

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service