Passive solar data

In 2010 we undertook a fairly substantial renovation to the house. One of the major goals of the renovation was to lower our energy expenditure through the inclusion of some passive solar design. I have already covered details of the construction in my posts on insulation and windows, but the summary would be that we drastically improved the insulation and air leakage of the house as well as converting the south wall from mostly opaque to having large windows along most of its length.

Since we still heat with baseboard electric, the improvement to our hydro bills was obvious the first year after the renovation. Recently, however, I have taken advantage of some easily accessible data to do some proper number crunching. The first set of data I had access to is that provided by my hydro company. As part of their electronic billing system, I can download .csv files of our electricity usage over the years. During the time we have had an account, the hydro company switched from meter readings to smart meters and then later to time-of-use pricing. This resulted in some irregular metering periods and made a straight month-to-month comparison infeasible. Instead, I consolidated the data into a spreadsheet of metering dates and the number of kWh used in the corresponding intervals, from which I calculated a figure of kWh/day for each metering interval. Knowing that the baseboards are turned off entirely for the summer, I used the periods metered between June and September of each year to calculate an average kWh/day for the non-heating period and set this as a baseline for the year. The difference between the kWh/day being used for any metering period and the baseline for that year could then be calculated, with metering periods below average being floored at zero. This resulted in a figure of “kWh/day above baseline” for each metering period, which should provide some indication of the electricity being used for heating. Although some additional electricity will also be used for lighting or entertainment during the shorter days and heating household water from its colder initial temperatures, these values should have remained somewhat constant through the years.

As can be seen in the graph, the renovations have made a substantial difference. Years prior to the renovation have been coloured in various shades of blue; the renovation year in salmon; the post-renovation years in various shades of green.

Comparison of electrical use over summer baseline by year, before and after passive solar renovations

Performance data for passive solar renovations

The second set of data to which I have access is historical weather data provided by Environment Canada. Using data for the nearest weather station, I compiled total Heating Degree Days (°C) for each metering period. When combined with the electricity data, this allowed for the calculation of (kWh/day over baseline)/Heating Degree Day(°C). The average could then be taken of periods between November and February.

Time Period Average Heating Degree Day(°C)/Day Average (kWh/day over baseline)/Heating Degree Day(°C)
Nov 2007 – Feb 2008 18.97 2.95
Nov 2008 – Feb 2009 20.34 2.99
Nov 2009 – Feb 2010 18.24 2.19
Renovations
Nov 2010 – Feb 2011 20.09 0.67
Nov 2011 – Feb 2012 15.25 0.34
Nov 2012 – Feb 2013 15.41 0.92
Nov 2013 – Feb 2014 19.84 0.38
Nov 2014 – Feb 2015 19.23 0.64

This provides only a rough overview of the trends but it is clear that the renovations did make a substantial difference to our electricity consumption. The installation of the slate floor is slated (heh) for this spring and I also intend to tackle an unanticipated source of heat loss in our current envelope once the weather is more favourable. It will be interesting to see what further benefits we garner from these two changes.


Data

Read Date Day DaysInBill kWh HDD HDD/day kWh/Day Base +Base per HDD
2006-11-17 321 30 1090 391.2 13.04 36.33
2006-12-18 352 31 1900 470.4 15.17 61.29
2007-01-19 19 32 2120 545.8 17.06 66.25 23.40 42.85 2.51
2007-02-19 50 31 3230 889.6 28.70 104.19 23.40 80.80 2.82
2007-03-20 79 29 2550 623.2 21.49 87.93 23.40 64.53 3.00
2007-04-19 109 30 2020 440.3 14.68 67.33 23.40 43.94 2.99
2007-05-17 137 28 1070 171.4 6.12 38.21 23.40 14.82 2.42
2007-06-18 169 32 880 54.5 1.70 27.50 23.40 4.10 2.41
2007-07-18 199 30 690 14.5 0.48 23.00 23.40 0.00 0.00
2007-08-17 229 30 620 0.7 0.02 20.67 23.40 0.00 0.00
2007-09-19 262 33 740 44.3 1.34 22.42 23.40 0.00 0.00
2007-10-18 291 29 770 89.4 3.08 26.55 23.40 3.15 1.02
2007-11-16 320 29 1430 307.4 10.60 49.31 23.40 25.91 2.44
2007-12-17 351 31 2700 633.1 20.42 87.10 23.40 63.70 3.12
2008-01-21 21 35 2860 661.1 18.89 81.71 23.47 58.25 3.08
2008-02-19 50 29 2750 653.4 22.53 94.83 23.47 71.36 3.17
2008-03-19 79 29 2580 649.9 22.41 88.97 23.47 65.50 2.92
2008-04-22 113 34 2230 448.4 13.19 65.59 23.47 42.12 3.19
2008-05-22 143 30 1220 236.4 7.88 40.67 23.47 17.20 2.18
2008-06-20 172 29 800 74.8 2.58 27.59 23.47 4.12 1.60
2008-07-22 204 32 690 4.8 0.15 21.56 23.47 0.00 0.00
2008-08-20 233 29 620 12.9 0.44 21.38 23.47 0.00 0.00
2008-09-22 266 33 770 60 1.82 23.33 23.47 0.00 0.00
2008-10-22 296 30 720 204.6 6.82 24.00 23.47 0.53 0.08
2008-11-20 325 29 1560 377.3 13.01 53.79 23.47 30.33 2.33
2008-12-18 353 28 2270 572.1 20.43 81.07 23.47 57.61 2.82
2009-01-21 21 34 3400 858.6 25.25 100.00 17.77 82.23 3.26
2009-02-20 51 30 2750 701.8 23.39 91.67 17.77 73.90 3.16
2009-03-24 83 32 2680 627.1 19.60 83.75 17.77 65.98 3.37
2009-04-23 113 30 1800 396.2 13.21 60.00 17.77 42.23 3.20
2009-05-25 145 32 840 184.2 5.76 26.25 17.77 8.48 1.47
2009-06-23 174 29 600 91.1 3.14 20.69 17.77 2.92 0.93
2009-07-23 204 30 560 19.4 0.65 18.67 17.77 0.90 1.39
2009-08-24 236 32 510 5.7 0.18 15.94 17.77 0.00 0.00
2009-09-23 266 30 473 46.4 1.55 15.77 17.77 0.00 0.00
2009-10-22 295 29 1154 265.5 9.16 39.79 17.77 22.03 2.41
2009-11-23 327 32 1493 355.3 11.10 46.66 17.77 28.89 2.60
2009-12-21 355 28 1894 510.5 18.23 67.64 17.77 49.88 2.74
2010-01-21 21 31 1869 726.1 23.42 60.29 11.66 48.63 2.08
2010-02-22 53 32 1759 730.1 22.82 54.97 11.66 43.31 1.90
2010-03-24 83 30 1112 469.1 15.64 37.07 11.66 25.41 1.63
2010-04-22 112 29 696 274.2 9.46 24.00 11.66 12.34 1.31
2010-05-20 140 28 562 192.4 6.87 20.07 11.66 8.42 1.22
2010-06-21 172 32 394 23.3 0.73 12.31 11.66 0.66 0.90
2010-07-21 202 30 345 13.8 0.46 11.50 11.66 0.00 0.00
2010-08-23 235 33 375 1.7 0.05 11.36 11.66 0.00 0.00
2010-09-21 264 29 332 66.9 2.31 11.45 11.66 0.00 0.00
2010-10-21 294 30 437 216.7 7.22 14.57 11.66 2.91 0.40
2010-11-22 326 32 540 378 11.81 16.88 11.66 5.22 0.44
2010-12-21 355 29 946 593.1 20.45 32.62 11.66 20.96 1.03
2011-01-24 24 34 1266 852.2 25.06 37.24 18.15 19.08 0.76
2011-02-23 54 30 1001 724.5 24.15 33.37 18.15 15.21 0.63
2011-03-24 83 29 786 550.1 18.97 27.10 18.15 8.95 0.47
2011-04-21 111 28 753 428 15.29 26.89 18.15 8.74 0.57
2011-05-26 146 35 594 231.1 6.60 16.97 18.15 0.00 0.00
2011-06-24 175 29 544 32.8 1.13 18.76 18.15 0.61 0.54
2011-07-26 207 32 598 1.1 0.03 18.69 18.15 0.53 15.56
2011-08-25 237 30 484 1 0.03 16.13 18.15 0.00 0.00
2011-09-26 269 32 609 58.3 1.82 19.03 18.15 0.88 0.48
2011-10-26 299 30 546.97 192.9 6.43 18.23 18.15 0.08 0.01
2011-11-01 305 6 113.39 84.9 14.15 18.90 18.15 0.75 0.05
2011-11-24 328 23 420.73 266.6 11.59 18.29 18.15 0.14 0.01
2011-12-23 357 29 625.98 466 16.07 21.59 18.15 3.43 0.21
2012-01-27 27 35 974.19 683.9 19.54 27.83 16.49 11.34 0.58
2012-02-28 59 32 872.55 612.1 19.13 27.27 16.49 10.77 0.56
2012-03-28 88 29 682.22 320.2 11.04 23.52 16.49 7.03 0.64
2012-04-30 121 33 684.81 384.7 11.66 20.75 16.49 4.26 0.37
2012-05-01 122 1 22.77 8.5 8.50 22.77 16.49 6.28 0.74
2012-05-30 151 29 594.34 75.6 2.61 20.49 16.49 4.00 1.53
2012-06-28 180 29 508.2 37.7 1.30 17.52 16.49 1.03 0.79
2012-07-30 212 32 505.83 0 0.00 15.81 16.49 0.00 #DIV/0!
2012-08-29 242 30 463.07 8.4 0.28 15.44 16.49 0.00 0.00
2012-09-28 272 30 516.39 89.9 3.00 17.21 16.49 0.72 0.24
2012-10-30 304 32 783.09 243.2 7.60 24.47 16.49 7.98 1.05
2012-11-01 306 2 55.27 24.4 12.20 27.64 16.49 11.14 0.91
2012-11-28 333 27 748.4 387 14.33 27.72 16.49 11.22 0.78
2013-01-02 2 35 1089.71 522.5 14.93 31.13 17.83 13.30 0.89
2013-01-31 31 29 982.78 375 12.93 33.89 17.83 16.06 1.24
2013-03-04 63 32 1142.08 725.2 22.66 35.69 17.83 17.86 0.79
2013-04-04 94 31 913.7 427.4 13.79 29.47 17.83 11.64 0.84
2013-05-01 121 27 577.48 268.3 9.94 21.39 17.83 3.56 0.36
2013-05-03 123 2 33.84 5.6 2.80 16.92 17.83 0.00 0.00
2013-06-04 155 32 606.22 138.3 4.32 18.94 17.83 1.11 0.26
2013-07-04 185 30 548.51 29.6 0.99 18.28 17.83 0.45 0.46
2013-08-02 214 29 477.58 6.2 0.21 16.47 17.83 0.00 0.00
2013-09-04 247 33 581.82 16.5 0.50 17.63 17.83 0.00 0.00
2013-10-03 276 29 508.53 111 3.83 17.54 17.83 0.00 0.00
2013-11-01 305 29 517.33 229.4 7.91 17.84 17.83 0.01 0.00
2013-11-04 308 3 52.89 50.5 16.83 17.63 17.83 0.00 0.00
2013-12-02 336 28 629.47 468.6 16.74 22.48 17.83 4.65 0.28
2014-01-02 2 31 1041.51 717.8 23.15 33.60 18.42 15.17 0.66
2014-02-03 34 32 1224.51 833.1 26.03 38.27 18.42 19.84 0.76
2014-03-03 62 28 991.48 793.7 28.35 35.41 18.42 16.99 0.60
2014-04-01 91 29 871.16 629.9 21.72 30.04 18.42 11.62 0.53
2014-05-01 121 30 621.87 374.6 12.49 20.73 18.42 2.31 0.18
2014-06-02 153 32 600.56 147.7 4.62 18.77 18.42 0.34 0.07
2014-07-02 183 30 568.39 21 0.70 18.95 18.42 0.52 0.75
2014-08-01 213 30 531.96 17.2 0.57 17.73 18.42 0.00 0.00
2014-09-02 245 32 583.94 20.4 0.64 18.25 18.42 0.00 0.00
2014-10-01 274 29 550.39 97.8 3.37 18.98 18.42 0.56 0.16
2014-11-01 305 31 695.79 256.5 8.27 22.44 18.42 4.02 0.49
2014-11-03 307 2 59.53 27.1 13.55 29.77 18.42 11.34 0.84
2014-12-01 335 28 867.23 482.4 17.23 30.97 18.42 12.55 0.73
2015-01-02 2 32 1010.33 601.3 18.79 31.57 21.64 9.93 0.53
2015-02-02 33 31 1186.27 806.2 26.01 38.27 21.64 16.62 0.64
2015-03-02 61 28 1164.3 882.5 31.52 41.58 21.64 19.94 0.63
2015-04-01 91 30 882.54 602.9 20.10 29.42 21.64 7.78 0.39
2015-05-01 121 30 696.09 329.5 10.98 23.20 21.64 1.56 0.14
2015-06-01 152 31 600.55 107.2 3.46 19.37 21.64 0.00 0.00
2015-07-02 183 31 651.7 43 1.39 21.02 21.64 0.00 0.00
2015-08-04 216 33 773.03 7.6 0.23 23.43 21.64 1.78 7.74
2015-09-01 244 28 637.01 17.1 0.61 22.75 21.64 1.11 1.81
2015-10-01 274 30 649.01 55.2 1.84 21.63 21.64 0.00 0.00
2015-11-01 305 31 622.65 265.2 8.55 20.09 21.64 0.00 0.00
2015-11-02 306 1 25.23 8.6 8.60 25.23 21.64 3.59 0.42
2015-12-01 335 29 550.03 347.6 11.99 18.97 21.64 0.00 0.00
2016-01-04 4 34 806.78 526.1 15.47 23.73 21.64 2.09 0.13
2016-02-01 32 28 990.89 608.4 21.73 35.39 21.64 13.75 0.63

 

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