home electric progress 4

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I have changed the slope of my electricity demand and it is quite easy to see with a simple tool.

This chart [click any pic to enlarge] shows my actual kWh/month graphed against how cold it got in the area for the last six years.

The three lines at the top are ancient history, my first three years here, before my changes described in this blog. They cluster well. As the outside temp falls I use more electricity (for various reasons but mostly the furnace motors).

The blue line is the 2016-2017 heating season. Parallel but noticeably lower.

2017-2018 (last year, purple) is lower still.

I've just plotted this year (black line) to date even though winter isn't finished. This year is different!

This year 2018-2019 I have a new furnace and six new windows. This line is not parallel to the others, it rises less (less electricity used) with increased degree days.

This means my house is less susceptible to cold from an electricity use point of view.

You can track your data to see the electrical effect of changes you make to your home in a very clear way. You only need one number from each electricity bill and the degree days closest to you.

Here's how I do it: I use a simple spreadsheet because that's the way I am most comfortable making a graph. I make a list of three columns to organize my data: the date, the kWh and the degree days.

The total kWh used each month is clearly shown on your bill. Here are mine, listed by month.

Next you add your weather data, the degree days near you. I get mine here.

Then I graph the points and add a regression line. You can do that with a ruler and some graph paper. I won't give you step by step since there are many ways and much software to do that - your choice. You compare the "best fit" lines of individual heating seasons, or cooling seasons using cooling degree days if you are cooling rather than heating (or both?!).

Then I show the regression lines but not the data. It's a whole lot easier to see what is going on without the data points in view especially when plotting multiple years.

Another view of my usage, December last six year kWh totals. I am using less electricity.

Update Feb 12: My usage of On-Peak has gone down! This chart shows my average On-Peak kWh per day for the months Nov-Feb for the past six years. I adjusted the figures for heating degree days to make all the winters equivalent.

Electricity used during the Peak periods often contributes to the need for my utility to run peaker gas generators producing more CO2. So they make it more expensive for me to buy.

This is my current pricing and TOU periods with HydroOne. On-Peak is twice the price (+103%) of the base rate. We also have a Mid-Peak rate which is 45% higher than the base rate.

My On-Peak is largely the "stuff I can't turn off", like the furnace in winter.

My On-Peak usage is an indication of the absolute minimum kWh I would need to produce in order to be electricity self sufficient.

I had hoped with the furnace and window upgrade that the latest reduction would be more significant.

However the chart suggests that my gains are harder to get from here on.

Thanks for your interest.

George Plhak
Lions Head, Ontario, Canada

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