Short cycling refers to furnaces cycling on and off frequently. When a furnace is working properly, it shouldn’t turn on and off, and this short cycling can be a sign of a major problem with your heating system.
1. Dirty furnace filters
Dirty or clogged furnace filters can often be the cause of a range of furnace issues, and it’s one of the most common causes of short cycling. A dirty furnace filter that is causing your furnace to cycle on and off makes your furnace work harder than it should, and could cause major damage resulting in costly repairs. Replace your dirty or clogged furnace filters so your furnace can resume blowing air efficiently.
2. Problems with your thermostat
Think of your thermostat as the brain of your furnace. If your thermostat begins to malfunction, or the settings aren’t set properly, your furnace may begin to act abnormally. If your furnace is cycling on and off, check to make sure your thermostat is working properly and, if it isn’t, have it repaired or replaced. Also ensure that your thermostat isn’t located near a heat source like direct sunlight or a register.
3. Your furnace isn’t the right size for your home
While the other two potential furnace problems are a relatively easy fix, having a furnace that’s too big for your home is the worst case scenario when it comes to short cycling. If you have a furnace that’s oversized, it will heat your home too quickly and shut off. If your furnace continues to do this, it will start to wear down more quickly and its lifespan will be shortened.
Unfortunately, the only real fix for this issue is to replace your furnace with a new furnace that’s sized appropriately for your home. An HVAC professional will be able to do a load calculation and provide you with the appropriate specifications for your new unit.