Our furnace is a Rheem 80 series (I believe is what I recall). One speed fan I believe. So, 80% efficient. Insulation on home is, eh... Decent but not great. 1990 build and probably decent for that time period. When it's 20° to 40° the gas furnace was turning on and blowing heat for about 5-6 minutes, shutting off for about 12-15 minutes (total cycle time about 15-20 minutes or 3-4 cycles per hour). It just seemed weird to me that the thermostat is constantly at 68 and never drops before kicking on again. I checked the settings on the thermostat and it was set to a CPH of 5 for heating. Which is in the recommended range from the thermostat manual for a furnace less than 90% efficient.
I'd prefer that it drops a degree or two before kicking on so I lowered the CPH to 2 on the t-stat and I've been timing the cycles this morning. It's about as cold as it gets right now and rarely gets lower than the 20's for lows and often in the 30's for lows and mid-40's for highs.
Instead of running for 5-6 minutes, the last couple times it's been running for 7-9 minutes and then off for about 17 minutes. So about 2-3 cycles per hour.
Any harm to the furnace setting the CPH to 2 with these run times? Is it easier or harder on a furnace to run a few minutes longer but fewer times per hour? I've read it's easier on the furnace to run about 10-15 minutes at a time because it's the starting up that wastes the most energy and causes the most wear and tear. Is this also true on a single speed, 80% furnace?
Thanks if you have knowledge of HVAC.
I'd prefer that it drops a degree or two before kicking on so I lowered the CPH to 2 on the t-stat and I've been timing the cycles this morning. It's about as cold as it gets right now and rarely gets lower than the 20's for lows and often in the 30's for lows and mid-40's for highs.
Instead of running for 5-6 minutes, the last couple times it's been running for 7-9 minutes and then off for about 17 minutes. So about 2-3 cycles per hour.
Any harm to the furnace setting the CPH to 2 with these run times? Is it easier or harder on a furnace to run a few minutes longer but fewer times per hour? I've read it's easier on the furnace to run about 10-15 minutes at a time because it's the starting up that wastes the most energy and causes the most wear and tear. Is this also true on a single speed, 80% furnace?
Thanks if you have knowledge of HVAC.