TalkAbout Jazz from western Colorado


Side
Side /
Radius
Perimeter
lineal feet
Area
square
feet
Ratio
area to
perimeter
wall
area
@8'tall
R-
value
Outside
Temp
deg F
BTU/hr
Heat
Loss
Circle
n/a
17.8
112.1
1,000
8.9
897
11
10
4,892
Octagon
n/a
14.4
115.1
1,0008.7
921
11105,024
Square
31.6
31.6
126.5
1,0007.9
1,012
11105,520
Rectangle
(50' x 20')
50
20
140.0
1,0007.1
1,120
11106,109
Rectangle
(100' x 10')
100
10
220.0
1,0004.5
1,760
11109,600
Completed
House
n/a
n/a
300.0
1,0003.3
2,400
111013,091
Rectangle
(1000' x 1')
100
1
2002.0
1,0000.5
16,016
111087,360

Source: Brian Propp
ICS Rocky Mountain
Manufacture of Structural
Insulated Panels (SIP's)
ICS-Rocky Mountain

Comments:

  • It seems the bottom line is that if we want to get a handle on our energy consumption we may need to rethink the basic design used in our buildings.

    • -Joe

  • A sphere has the minimum surface area for any fixed volume; hence, spherical houses would have the least heat loss (proportional to surface area) for a fixed volume. Likewise, a circular cylinder has the least surface area for any cylindrical solid. The rectangular solid with minimum surface area has a square cross-section.

    The big problems with houses with circular (or non-rectangular) cross-sections are

    • standard furniture and fixtures do not fit very well--kitchen cabinets, stoves, ovens, refrigerators, chairs, beds, tubs, ... have flat sides and right-angled edges. They are difficult to place against non-planar walls or next to each other along a curved wall.
    • the high waste in construction materials, most of which come in rectangular shapes.

      For example, carpeting a 12' diameter circle would waste 21.2% of a piece of 12' x 12' carpeting.

      Octagons have least waste of non-rectangular solids since 45 degree cuts can be used either on the other side (if the material is reversible) or along the same side if the material can be rotated. Hence, they are good for tile or carpet, but poor for tongue-groove pre-finished flooring.

-Ron