My thermostat runs my furnace about once every hour when it is 20 degrees and I am thinking about adjusting the swing on the thermostat to a lower number so that the system keeps a more consistent temp. Is this going to cost me more in gas. The swing will allow the system (set at 62 for heat) to come on at 61 and run it up to 63. So the swing is 3 degrees. I figure I might go to 2 or one to cycle the system more and be more consistent temp. Any thoughts?
thermostat setting
Jan 05, 2008
14 Replies
correction, the current swing is 0
Give it a try and see what happens. It sounds like your furnace is oversized though, ideally on the coldest days you ever see, it should run nearly constantly to maintain the desired temperature, though 61F is much colder than usual, I would size it to maintain 70 so you have a bit of margin.
It might take 5 minutes for the furnace to get to full efficency, running once per hour is not much 61f and a 3f swing for me is uncomfortable, 10 minute running cycles are short but I dought you will notice a difference narrowing the cycle
the cycle runs about 12 mins. and yes the furnace is too large by about 30,000 btu. Not installed when I was living here. Wil there be a diff in usage of gas though. I can go to lower setting on this thermostat, even though there is 0 swing right now. When I checked it said 0 swing at 63. Went to -1 and it dropped to 62. So I assume that will keep it right on the mark of 62? Obviously dont want to go lower than the set temp though.
I like even heat and cooling. I have an up to date thermostat that can be set to 0.2 of a degree. The heat comes on often that way but I waste not one BTU of heat because I run the fan 24/7. Having it set that way with auto fan will waste some heat because the plenum has to pre-heat before the blower comes on. Not a lot of waste but some.
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What I did was actualy cut gas to the furnace to lower btu input, I just turned down on the supply valve as it was running so I could see the flame and had a thermometer inserted just above the heat exchanger, I just cut it maybe 10-15f it evened heat and lowered output. If you have a dual stage setup be sure its running on low stage.
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I measured the diameter of the gas nozzle in my furnace, it agreed with the BTU rating, then I filled in the nozzle and redrilled it out at a smaller diameter - about 80% of the original gas flow. So now I have a smaller flame and the furnace runs longer, but the gas consumption is definitely down based on BTU's burned per degree days. I also run my furnace blower continually when the temps are below about 20F to keep the various parts of my 4-level split-level home more evenly heated. I do pay some in electricity for comfort, but that's what we have furnaces and electricity for (to dangle a preposition).
Running the fan 24/7 costs money, too.
It must be torture for you to leave the house. What are you, the princess who could feel the pea through 20 mattresses?
10 minute running cycles are short but I dought you
I hope you checked the flue temperatures before and after, and have a good CO monitor.
Most electricians say the difference in the starting windings usage and running 24/7 about balance out so why not be comfy.
What you need is the newer varitable speed fans. They come on when the heat comes on and run at a slow speed. As you heat up, the fan speeds up.
I doubt "most electricians" say that, and if they do, they're wrong.
Whatever. Certainly not worth arguing over [g]
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