It Seems To Be Working

Last July, I had a major update to my HVAC system, getting a whole new unit and a sparkly new thermostat.  I was sort of excited about the thermostat because it was programmable.  However, at the time, my ex and I were working opposite shifts and so I never had the opportunity to exploit the scheduling features.

Well, as circumstances changed a while ago, I only recently decided to revisit these scheduled temperature changes.  I actually wouldn’t have thought much about it if it wasn’t for the cats.  The cats were enjoying hanging out on the patio in the middle of the day and it’s like 90 degrees outside.  While I watched them bake, I was reminded that cats internal body temperature is higher than humans and how an average house temperature is actually really cold for them.  That’s why they’re always looking to curl up in warm places, like sunbeams and beds and laps.

I thought, I guess I could raise the house temp a little for them, and realized, I can do it every day while I’m not around.  That’s why I have this programmable device.  And while I thought the idea was novel, I also questioned whether it would really work.  To me, it didn’t seem like anyone would really be fooled by this scheme.  Sure, you let you house temp rise all day and save the money with the AC not running, but then you have to cool it all back down, so your AC runs hard to bring it back down.  Shouldn’t it be cheaper to maintain than to binge and purge?

I set my thermostat to let the house warm to 79 degrees while I was at work and return it to 74 for the time I would be at home, which includes all day Saturday and Sunday.  After a full month of this, I was able to use my electric company’s data tools to actually see if this was a noticeable improvement.  This is how last month looked.


The significance of the rising and falling isn’t anything, but the peaks are.  Every peak happens on a weekend, when the AC is keeping the house at 74 all day.  The only other major contributor to my energy usage would be laundry day, which actually varies, so it’s not really identifiable in the graph.

While that seems interesting for a month’s timeframe, if we zoom out to 14 month’s worth of data, you can see some other things of note.


Here, you can definitely see when I replaced my HVAC unit.  The electrical usage dropped right away.  Of course we get into fall and winter, so things are light at that time.  But you can see last month, I had a decent amount of tier 3 usage (which costs more).  This month, in the first graph, I haven’t hit tier 3 yet, so I’m definitely ahead of the game.

Since the cats actually seem to like the warmer house, I think I may bump the day temp to maybe 84.  The only issue that causes is that my office and my master closet stay hot for quite a while, since there’s no AC vents there.  But, I can manage to deal with that if I’m saving a lot of electricity.  I keep a budget of $350/mo for electric, because that’s actually what it used to be in the summer.  But this year, I’m averaging about half that.  That’s how to promote conservation, make it pay.

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