July Energy Usage

I am still seeing incredible benefits to the insulation and air sealing that I did in March through May of this year.

Remember, though, that I had 3 other people here last July with 3 TVs and the computers and routers were not completely switched off.

I don't think I set the temperature lower last year because my sister and her husband got cold in the house and my brother lived in the basement where it is 10 degrees cooler. This summer has been substantially hotter than last summer. The chart  below shows some July temperature averages from the past 15 years. The lowest temperature for July 2015 was 67 degrees, the highest 98. The lowest MAXIMUM temperature was 82 while there was a day last July where the high was only 69. This year's average high temperature was 91.9 and the mean temperature was 82. Last year's mean was 77.9. It has been much hotter this year which makes the drop in energy use even more impressive.

I will continue to monitor the energy use. My brother moved into his new home in September 2014 and my sister and her husband moved away in October so I should have better comparisons for one person living in the home after that time.

Also, remember that I insulated only to about a level of R-20 just over 1/2 of the current code requirements of R-38. When the weather cools off, I will be up in the attic again making some structural changes and increasing the insulation to around R-50.

Energy Benefits from Attic Insulation - June numbers

I got my Duke energy bill yesterday. My electric usage continues to be much, much lower than last year. I did have 3 more people here last year though. The one point I would like to make about that though is that none of them really ran the air conditioner more than I would have. My sister and her husband got cold in my house and my brother lived in the basement which is substantially cooler than upstairs. There were 3 TVs in the house at that time that was probably a significant energy drain. I don't have a TV. Also my computer and my router are on switches that are turned off when I am not using them.

Anyway, here are the numbers from June which was a very hot month. Days were often right at or above 100. I was very comfortable in my home.

Usage less than half compared to last year. I am very pleased with that and the improved comfort level.

Attic Insulation - May Energy Report - Proof that it WORKS

I could't get my scanner to scan so I had to make do with an iPhone photo. 

In March and April I spent many hours in my attic air sealing and insulating hoping that getting the insulation to an R-20 level would make a difference. I have plans for putting in 10-12 inches of blown-in cellulose in the fall after I do some more work up there such as beef up the rafter supports for one thing as my roof is only held onto the house by a few nails toenailed to the rafters.

I elected to use denim because I was SO tired of itching from all the mineral wool insulation which I love, but I do not love the itch that comes with it. Denim is a dream in terms of installation compared to mineral wool. Still mineral wool, specifically Roxul (Carlton, my carpenter, calls it Roxie), is my all time favorite insulation. Just remember that even when I talk fondly about denim as an insulation material.

Anyway, I got my May energy report from Duke Energy and I used about 15 KWH per day for a total of 428. Though on my energy report it shows only 368 for the month. They must have used a different interval for their report.

I have saved all my energy bills for more than 10 years, but I can't find the complete collection for a better analysis. I do have some from this year and last though for comparison. My sister and her husband lived with me from December 2013 to October 2014. Also my younger brother lived in my basement while we were building his house from sometime in 2013 to September 2014. You can see the drop in consumption in November with only one occupant, but I was above the green energy efficient home during the winter, probably from heat loss through my attic until I started insulating the attic in March.

So I have graphic proof that just getting my attic to R-20 has made a big difference in energy use. I will tell you that the house is so much more comfortable.

One of these days I hope to show a chart of energy use correlated with the work I've done on the house - metal roof, 2 inches of polyiso under the HardieBoard siding, new windows, attic insulation, etc, but that will take some research.