How does the "swing" setting of a thermostat affect operating cost and environmental concerns?

We have a forced-air gas furnace for a three-story house and the Swing setting (range of temperatures regulating the on/off operation of the furnace) is currently 3 degrees. What cost and/or environmental effects would result from increasing or decreasing that swing setting. Thanks.How does the %26quot;swing%26quot; setting of a thermostat affect operating cost and environmental concerns?The lower you set this, the more your thermostat is going to try to keep the space closer to your setpoint. It will do this by firing your furnace more frequently and for shorter periods (short-cycling).



Going in the opposite direction, you will find that your furnace has to run less frequently, but it will run longer when it does run. Theoretically this should be more efficient, as the furnace becomes most efficient after it has warmed for a few minutes and reached a steady state. Realistically, who wants to endure wildly fluctuating temperatures in their house for the sake of a perceived improvement in efficiency?



If you're really concerned about the efficiency of your furnace, then have an experienced furnace and boiler tech come check it out. This is something you should have done at the beginning of EVERY heating season, and you preferably want it done by someone with a little grey in his hair. He'll check the heat exchanger for cracks, check the draft and do a combustion gas analysis, at minimum. I've seen a lot of people screw up the draft and the gas analysis, and you can lose a lot of efficiency and money out your flue that way. It doesn't matter what the efficiency rating of your furnace is or how intelligent your thermostat is if you don't have the combustion process itself optimized.