December 28th, 2007 - 2-stage furnace
Back about 5 years ago, when we bought a new furnace, we were sold on a 2-stage furnace. The description of how it worked given by the salesman made sense–something about how it blows continually keep heat circulated leading to more comfort without the furnace going full blast all the time.
I never quite understood why it didn’t seem to actually do this unless we turned the fan to ON (as opposed to Auto, which runs only when the furnace turns on).
This winter, I just found the air blowing around when it was 67 (downstairs, colder upstairs) just to darn cold and turned the fan off. It didn’t seem to change our electrical usage (to my great surprise–you’d think a fan on 24 hours a day would use a noticeable about of electricity) but our comfort went up! (The effect is based on checking the electric readings for 2 days before and after turning it off. The weather was about the same the entire time–bitterly cold.)
And I finally went looking online for what’s so great about 2-stage furnaces. We weren’t told the right thing! It’s actually that on average days, it runs at 70% (or some number) and only on the coldest days does it run at 100% (I think that usage of gas, not efficiency). But, in order to do this, you have to have a programmable thermostat made for 2-stage furnaces.
Funny thing about that free programmable thermostat they installed with the furnace: It’s for single stage furnaces! I was led to this by Earth Aid Enterprises, which offers kits of greening supplies at a discount. I looked at their thermostats and discovered notes that some were for 2-stage furnaces! That set me off on the check on our’s. And this weekend, I’ll probably put together a kit including an appropriate thermostat. I’m hoping it has a negative affect on our gas usage (negative is correct right, since I want it to go down?) and a positive one on our comfort level. (67 is actually on the chilly side for me and cold for Eric but we put up with it.)
I’ll get one that includes 7 days of programming. Our current one is 5-2, meaning on the weekends, it takes the settings for the other days and skips the last 2 (night and morning kept, day and evening tossed). That doesn’t work for us because we have lower settings in early morning since there’s a gap between when I get up and Eric gets up and stays home. It kicks in programming every 4-6 hours (or something, we don’t pay attention) so we have to manually change the temp back up a few times a day. It’s annoying–survivable, but annoying. Would rather have it programmed in.
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October 29th, 2008 at 7:40 am EDT
[…] Speaking of which: Last winter, I learned we had the wrong thermostat–we have a 2-stage furnace but had a 1-stage thermostat. I finally got around to buying a new thermostat this past month. I ordered it the day before we had the heating folks come in for the annual furnace checkup. Eric mentioned it to him, thankfully. He looked at things and said that we’d need two wires run up to the thermostat. One for the dual stage part and one so that the battery was backup instead of constant (not necessary, but nice and cheaper probably). We *could* do that ourselves, except that’s totally not in our abilities. […]