From: clare@snyder.on.ca   
      
   On Tue, 3 Feb 2026 11:34:46 -0500, Harvey Sanenbum   
    wrote:   
      
   >A couple decade old oil burner heats my home.  Question: Is it more cost   
   >effective to turn down the heat while sleeping and then increase the   
   >thermostat during the day, or to more or less keep the thermostat near   
   >constant?   
   >   
   >I've done the former (turning it down at night) since I can remember   
   >but, with the severely below normal temps outdoors lately, it has to run   
   >a long time to get up to room temp during the day, which has caused me   
   >to rethink my process.   
   >   
   >Thanks.   
    Ours is a relatively well insulated 50 year old house in south   
   central Ontario heated with gas and a Tempstar 80%+ furnace. It's been   
   -20C here for weeks - we keep the house at about 21C during the day   
   and knock it down to about 17 at night. This means the upstairs   
   bedroom drops to about 15C overnight. The thermostat goed back to 21   
   at about 7AM and the bedroom is back to 18ish and the rest of the   
   house up to 21 by 8:30.   
   The furnace might run 1.5 to 2.5 hours during the turn-down period and   
   a total of 7.5 to 8.5 in a 24 hour period. The turndown period is   
   about 9 hours - say just over 30% - so during  roughly 90% of the time   
   it runs 1/3 of the time, and during the other 30% it runs closer to 20   
   to 25% of the time. Not a HUGE savings - but keep in mind the "down"   
   time is the coldest part of the day - and often the windiest, with no   
   solar heat gain - so it seems to be worth it for us.   
    It is a 2 stage furnace and it VERY SELDOM kicks up to the high burn   
   -50,000 / 70,000 BTU input, 40,000/60,000 nominal output. It kicks to   
   high after 12 minutes on low if the temperature hasn't recovered.   
    I haven't put a timer or counter on the high fire recently but when   
   it was installed 23 years ago, with the blower set too dlow so it was   
   short cycling it virtually NEVER switched to high. I reset the fan   
   speed to get the temperature rize down where it belongs and since then   
   it has never short cycled and I have not heard it kick up to high fire   
   - but it MIGHT during morning recovery. The furnace is about 30%?   
   oversize - a 35/55000BTU would have been the correct furnace according   
   to heat-loss calculations   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)