Tessa Hill and Dennis Odin Johnson
Bear Creek Dome - North Branch, Minnesota
- Model: 1800 mid profile, 49' diam. dome home
- Location: North Branch, Minnesota.
Department of Energy Zone 7A (severe cold-moist) 9000 heating degree days.
- House size: 3200 SF; slab on grade. Main floor 2100 sf, upper floor 1100 sf.
- Specifications: 18" thick dome walls and dome roof, 16" fiberglass insulation (R-Value=57 in triangles, R-Value=62 in riser walls), vented dome shell; slab has 2" styrofoam under and 11" styrofoam on edge of slab. Blower door test was .06 ACH
- Heating system: Radiant floor in 4" concrete slab using 1500 lf of PEX tubing circulating water. Heating unit is 14 KW Seisco Electric "instant on" boiler with a secondary natural gas "Munchkin" boiler that you can switch to manually. Electric rate is off-peak interruptable rate of 4.2¢ /KW. * Note: Rate increase to 4.8¢ /KW in Feb. 2008 (14% increase).
- Built: 2007, moved into November 2007.
- Heating costs: See below.(Electric billings run from the 7th of each month. Natural gas billings are from the 17th).
- Air conditioning costs: The Summers of 2008, 2009 and 2010 had zero A.C. costs. The outside temps were 90°-95° F many days, yet the highest inside temps were 72°-74° F.
Winter 2007-2008
Radiant floor heating |
|
Month |
Cost |
KW Used |
| July 07 |
$0 |
None |
| August 07 |
$0 |
None |
| September 07 |
$0 |
None |
| October 07 |
$71 |
1680 kw |
| November 07 |
$153 |
3640 kw |
| December 07 |
$156 |
3720 kw |
| January 08 |
$165 |
3940 kw |
| February 08 |
$143* |
2980 kw |
| March 08 |
$97 |
2020 kw |
| April 08 |
$73 |
1520 kw |
| May 08 |
$16 |
340 kw |
| June 08 |
---- |
---- |
| Total: |
$765 |
16,660 KW |
| |
Winter 2008-2009
Radiant floor heating |
| January, 2009, was extremely cold, the 4th coldest January on record. All of the days were below 32° (0° C) with some periods of 4-5 days where it never was warmer than 0° (-18° C). |
Instantaneous hot water gas heater |
Month |
Electric Heat
4.8¢ /kw |
KW Used |
|
Natural gas base monthly fee |
Actual gas used |
| July 08 |
$0 |
None |
|
$8 |
$4.01 |
| August 08 |
$0 |
None |
|
$8 |
$4.73 |
| September 08 |
$11 |
220 kw |
|
$8 |
$3.82 |
| October 08 |
$55 |
1140 kw |
|
$8 |
$1.59 |
| November 08 |
$152 |
3160 kw |
|
$8 |
$5.10 |
| December 08 |
$216 |
4500 kw |
|
$8 |
$3.86 |
| January 09 |
$244 |
5080 kw |
|
$8 |
$6.04 |
| February 09 |
$150 |
3120 kw |
|
$8 |
$3.64 |
| March 09 |
$140 |
2160 kw |
|
$8 |
$3.21 |
| April 09 |
$30 |
620 kw |
|
$8 |
$4.21 |
| May 09 |
$8 |
180 kw |
|
$8 |
$2.51 |
| June 09 |
|
|
|
$8 |
$3.96 |
| Total: |
$871 |
16,840 KW |
Total |
$96 |
$46.68 ($3.89) |
| |
Winter 2009-2010
Radiant floor heating |
Instantaneous hot water gas heater |
Month |
Electric Heat
4.8¢ /kw |
KW Used |
|
Natural gas base monthly fee |
Actual gas used |
| July 09 |
$0 |
None |
|
$8 |
$2.26 |
| August 09 |
$0 |
None |
|
$8 |
$1.71 |
| September 09 |
$25 |
520 kw |
|
$8 |
$2.11 |
| October 09 |
$97 |
2020 kw |
|
$8 |
$4.28 |
| November 09 |
$115 |
2400 kw |
|
$8 |
$4.62 |
| December 09 |
$223 |
4640 kw |
. |
$8 |
$3.07 |
| January 10 |
$188 |
3920 kw |
|
$8 |
$5.00 |
| February 10 |
$153 |
3200 kw |
|
$8 |
$3.88 |
| March 10 |
$ |
kw |
|
$8 |
$5.96 |
| April 10 |
$ |
kw |
|
$8 |
|
| May 10 |
---- |
None |
|
$8 |
|
| June 10 |
---- |
None |
|
$8 |
|
| Total: |
$801 |
16,700 KW |
Total |
$96 |
$32.89 ($3.65) |
| |
Winter 2010-2011
Radiant floor heating |
Instantaneous hot water gas heater |
Month
(Dates) |
Electric Heat
4.8¢ /kw |
KW Used |
Gas Heating Cost |
Heating Therms Used |
Avg.
Temp.
(F) |
Natural gas base monthly fee |
Actual gas used |
| 7/9/10 - 8/8/10 |
---- |
None |
|
|
76 |
$8 |
$5.64 |
| 8/8/10 - 9/8/10 |
---- |
None |
|
|
78 |
$8 |
$3.45 |
| 9/8/10 - 10/8/10 |
$22 |
460 kw |
|
|
69 |
$8 |
$3.94 |
| 10/8/10 - 11/7/10 |
$69 |
1440 kw |
|
|
60 |
$8 |
$3.84 |
| 11/7/10 - 12/9/10 |
$175 |
3640 kw |
|
|
47 |
$8 |
$3.69 |
| 12/9/10 - 1/10/11 |
$229 |
4780 kw |
. |
|
21 |
$8 |
$3.67 |
| 1/10/11 - 2/7/11 |
$145 |
3020 kw |
|
|
16 |
$8 |
$6.96 |
| 1/18/11 - 2/18/11 |
|
|
$65 |
73 |
8 |
$8 |
$4.50 |
| 2/19/11 - 3/20/11 |
|
|
$96 |
108 |
27 |
$8 |
$4.50 |
| 3/20/11 - 4/18/11 |
|
|
$60 |
62 |
42 |
$8 |
$4.50 |
| 4/18/11 - 5/19/11 |
|
|
$32 |
33 |
52 |
$9 |
$4.50 |
| 5/19/11 - 6/19/11 |
|
|
$5 |
5 |
68 |
$9 |
$4.50 |
| Total: |
$640 |
13,340 KW |
$258 |
281 Th. |
|
$98 |
$54 |
| |
Winter 2011-2012
Radiant floor heating - Bear Creek Dome |
Instantaneous hot water gas heater
(used for baths, laundry, kitchen, etc.) |
Month
(Dates) |
Electric Heat
4.8¢ /kw |
KW Used |
Gas Heating Cost |
Heating Therms Used |
Avg.
Temp
F (C) |
Base monthly fee |
Actual gas used |
| 6/19/11 - 7/19/11 |
---- |
None |
|
|
76 (24) |
$9 |
$3.63 |
| 7/19/11 - 8/16/11 |
---- |
None |
|
|
78 (25) |
$9 |
$5.18 |
| 8/16/11 - 9/15/11 |
---- |
None |
|
|
71 (22) |
$9 |
$3.55 |
| 9/15/11 - 10/16/11 |
---- |
None |
|
|
62 (16) |
$9 |
$5.60 |
| 10/16/11 - 11/14/11 |
---- |
None |
$36 |
45 |
47 (9) |
$9 |
$4.50 |
| 11/14/11 - 12/15/11 |
---- |
None |
$89 |
107 |
32 (0) |
$9 |
$4.50 |
| 12/15/11 - 1/18/12 |
---- |
None |
$112 |
139 |
29 (-2) |
$9 |
$4.50 |
|
Kim and Steve Long - Perry, Iowa
- Model: 1500 low profile, 45' diam. dome home
- Location: Perry, Iowa.
Department of Energy Zone 5A (cold-moist) 6500 heating degree days.
- House size: 3600 SF total; 1700 SF basement, 1700 SF main floor, 200 SF loft.
- Specifications: 2x8 dome walls and dome roof. 7" sprayed-in place foam (R-Value=27), unvented dome shell, no vapor barrier, permanent treated wood foundation walls with 2x8 studs, 7" sprayed-in-place Icynene "soft" foam (R-Value=27). Basement walls have one side approximately 2/3 out of the ground. Blower door test was .03 ACH
- Heating system: Radiant floor in basement concrete slab using PEX tubes circulating water and PEX tubes under plywood of main floor with insulation under; heating unit is "Munchkin" natural gas boiler. There is a natural gasburning fireplace on the main floor, however; it is not used for the main heating. It is rated at 42,000 BTU output with 86% efficiency.
- Built: 2006 (moved in March 2007)
- Heating costs: See below. Please note that the domestic hot water system is also operating with natural gas. The average usage is based on 30 therms per month and is not in the heating total. *Also note that this dome was not complete until Fall 2008. The insulation under the main floor had not been finished, and the heating costs decreased as the proper insulation was finalized. Billings run from the 10th of each month through August 2009, when they switched to show billings to the 27th of each month.
- Also note that due to rising energy costs, the cost per therm nearly doubled this past heating season. The price per therm is noted in the chart below.
Month |
Cost |
Price per
therm |
KW or Therms
Used |
|
| July 2007 |
$0 |
|
None |
| August 2007 |
$0 |
|
None |
| September 2007 |
$0 |
|
None |
| October 2007 |
$35 |
$.60 |
33 therms * |
| November 2007 |
$111 |
$.73 |
100 therms * |
| December 2007 |
$142 |
$.74 |
128 therms * |
| January 2008 |
$169 |
$.77 |
150 therms * |
| February 2008 |
$120 |
$.86 |
134 therms * |
| March 2008 |
$72 |
$1.00 |
80 therms * |
| April 2008 |
---- |
$1.02 |
---- |
| May 2008 |
---- |
$1.12 |
---- |
| June 2008 |
---- |
|
---- |
2007-2008
Total: |
$649.00*
(see note above) |
|
625
Therms |
Month |
Cost |
Price per
therm |
KW or Therms
Used |
Avg. Temperature |
Mean Avg.
Temperature |
| July 2008 |
|
|
|
|
|
| August 2008 |
|
|
|
|
|
| September 2008 |
|
|
|
|
|
| October 2008 |
|
|
|
|
|
| November 2008 |
|
|
|
|
|
| December 2008 |
|
|
|
|
|
| January 2009 |
|
|
|
|
|
| February 2009 |
|
|
|
|
|
| March 2009 |
|
|
|
|
|
| April 2009 |
|
|
|
|
|
| May 2009 |
$5 |
$.77 |
7 |
65 |
|
| June 2009 |
---- |
|
---- |
74 |
|
2008-2009
Total: |
$0
|
|
|
|
|
| |
| July 2009 |
---- |
|
---- |
72 |
|
| August 2009 |
---- |
|
---- |
74 |
|
| September 2009 |
---- |
|
---- |
68 |
|
| October 2009 |
$28 |
$.79 |
35 |
51 |
|
| November 2009 |
$43 |
$.86 |
50 |
48 |
|
| December 2009 |
$122 |
$.84 |
146 |
27 |
|
| January 2010 |
$129 |
$.95 |
136 |
17 |
|
| February 2010 |
$139 |
$.94 |
148 |
19 |
|
| March 2010 |
$63 |
$.89 |
71 |
41 |
|
| April 2010 |
$27 |
$.88 |
31 |
58 |
|
| May 2010 |
$22 |
$.88 |
25 |
62 |
|
| June 2010 |
---- |
|
---- |
74 |
|
2009-2010
Total: |
$573.00 |
|
642
Therms |
50.0 |
Mean Avg. Temperature |
| |
| July 2010 |
---- |
|
---- |
78 |
|
| August 2010 |
---- |
|
---- |
78 |
|
| September 2010 |
---- |
|
---- |
68 |
|
| October 2010 |
$6 |
$.98 |
6 |
60 |
|
| November 2010 |
$60 |
$.86 |
70 |
42 |
|
| December 2010 |
$109 |
$.87 |
125 |
23 |
|
| January 2011 |
$108 |
$.86 |
125 |
19 |
|
| February 2011 |
$108 |
$.87 |
124 |
27 |
|
| March 2011 |
$64 |
$.86 |
125 |
19 |
|
| April 2011 |
$29 |
$.90 |
32 |
50 |
|
| May 2011 |
$10 |
$.97 |
---- |
61 |
|
| June 2011 |
---- |
|
---- |
71 |
|
2010-2011
Total: |
$494.00 |
|
625
Therms |
49.7 |
Mean Avg. Temperature |
| |
| July 2011 |
---- |
|
---- |
80 |
|
| August 2011 |
---- |
|
---- |
78 |
|
| September 2011 |
---- |
|
---- |
66 |
|
| October 2011 |
$7 |
$.99 |
7 |
59 |
|
Joyce and Rich Peake - Arden Hills, Minnesota
- Model: 1250 Low Profile 40' diam
dome home
- Location: Mounds View, Minnesota.
Department of Energy Zone 6A (severe cold-moist) 8400 heating degree days.
- House size: 3200 SF; walk out basement 1350 SF, main floor 1450 SF, loft 450 SF
- Specifications: 15" thick dome
walls & dome roof,
12" fiberglass insulation (R-Value = 44), vented dome shell, riser walls 45" high, 15" thick with 15" fiberglass (R-Value=51)
Permanent treated wood foundation walls with 2x8 studs, 7 1/4" fiberglass insulation (R-Value = 27)
(Lower floor has 2x8 walls 3' in ground with a walk out patio door on one side.)
- Heating system: Forced air, natural gas, high efficiency furnace (no wood stove)
- Built: 1984
- Heating costs: (Billings run from the 12th of each month.)
Month |
Cost |
Cost per therm |
KW or Therms
Used |
|
| June 2007 |
$12.00 |
$1 |
4 |
| July 2007 |
$12.00 |
$1 |
4 |
| Aug 2007 |
$11.00 |
$1 |
3 |
| Sept 2007 |
$12.00 |
$1 |
4 |
| Oct 2007 |
$37.00 |
96¢ |
30 |
| Nov 2007 |
$96.00 |
$1.10 |
80 |
| Dec 2007 |
$112.00 |
$1.10 |
92 |
| Jan 2008 |
$116.00 |
$1.05 |
103 |
| Feb 2008 |
$106.00 |
$1.15 |
92** |
| March 2008 |
$65.00 |
$1.12 |
51 |
| April 2008 |
$28.00 |
$1.18 |
17 |
| May 2008 |
$8 |
base charge |
0 |
| June 2008 |
$8 |
base charge |
0 |
| Total: |
$530.00 |
|
398
Therms |
| Winter 2008-2009 |
| July, 2008 |
$8 |
base charge |
0 |
| Aug., 2008 |
$8 |
base charge |
0 |
| Sept., 2008 |
$8 |
base charge |
0 |
| Oct., 2008 |
$31 |
82¢ |
28 |
| Nov., 2008 |
$90 |
95¢ |
86 |
| Dec., 2008 |
$115 |
82¢ |
130 |
| Jan., 2009 |
$91 |
77¢ |
108 |
| Feb. 2009 |
$65 |
63¢ |
90 |
|
| March 2009 |
$32 |
53¢ |
45 |
| April 2009 |
$12 |
50¢ |
8 |
| May 2009 |
$8 |
base charge |
0 |
| June 2009 |
$8 |
base charge |
0 |
| Total: |
$476.00 |
|
495
Therms |
| Winter 2009-2010 |
| July 2009 |
$8 |
base charge |
0 |
| Aug. 2009 |
$8 |
base charge |
0 |
| Sept. 2009 |
$12 |
40¢ |
10 |
| Oct. 2009 |
$21 |
48¢ |
27 |
| Nov. 2009 |
$37 |
43¢ |
67 |
| Dec. 2009 |
$74 |
68¢ |
109 |
| Jan. 2010 |
$67 |
63¢ |
93 |
| ** Indicates rate increase |
|