Most systems should run about 2-3 cycles per hour. How long should the furnace or AC run in a given cycle? Typically 10-15 minutes in mild weather. The closer you get to the max design temperature in heating (0 Degrees) or cooling (90 Degrees) the longer the run cycle will be.Click to see full answer. Also to know is, why does my furnace cycle on and off frequently?Why a Clogged Furnace Air Filter Can Cause Your Furnace to Turn On and Off Repeatedly. If you remember from our orientation up above, the most common cause for your furnace to keep turning on and off is the High-Limit Switch, which turns the unit off if the temperature inside gets too high (as a safety precaution).Also, how often should your furnace turn on in winter? Believe it or not, in the coldest winter conditions, it is not uncommon for a furnace to turn on very frequently (between 3 and 8 times per hour). That’s because larger houses require more heat which, consequently, requires more work from the furnace. Also to know, what does it mean when a furnace is short cycling? A furnace “short cycles” when it turns off before reaching the desired temperature. This means that if your thermostat is set to 72 degrees, the furnace may shut down at 65 or 68 degrees, but will never reach 72 degrees. Short cycling can also be used to describe a furnace that turns on and off too often.How long can a furnace short cycle? Short cycle time: 3-7 minutes in most cases. They don’t produce noticeable temperature swings. When a furnace is too big, it can short cycle – start, heat up air very quickly that reaches the thermostat, and then shut down.