Is your furnace having trouble maintaining a consistent temperature in your home? If you set the thermostat at 68 but the temperature never seems to climb beyond 65, this indicates an issue. Below, you can learn more about some of the biggest causes of this and what you can do to help your family stay comfortable throughout the winter.

The Furnace is the Wrong Size

This is a common cause of temperature fluctuations, which will occur whether the furnace is too large or too small for your home. If it is too small, it will work overtime and never be able to bring the temperature up to what you’ve set; if it is too large, it will cycle on and off too quickly since it heats the air it brings in too quickly, and the air near the thermostat will warm quicker than the air in the rest of the house. This can also leave you too cold. Be sure that your furnace is the right size if you want a truly consistent temperature.

There’s a Problem with Your Thermostat

Another issue that can cause inconsistent temperatures is a faulty thermostat. If it misreads the temperature as being higher than it truly is, then your furnace will kick off and leave you feeling the cold. Programmable thermostats can sometimes fault, too, causing the furnace to kick on and off at inappropriate times throughout the day. This can have a significant impact on your comfort. If you’re curious, use a good thermometer next to the thermostat and take the temperature. If it is off by more than a degree or two, it’s definitely time for a new thermostat.

Faulty Fan or Incorrect Thermostat Settings

After the furnace kicks off – meaning the gas or electric burners shut off – the fan continues running for a few minutes to help move any heated air out of the ducts and boost efficiency. If the temperatures in your house are uneven, try changing the fan setting on the thermostat from “Auto” to “On”.  The “Auto” setting will only circulate air when the thermostat is calling for heat.  The “On” setting will constantly circulate air to help even out temperatures.  If the fan turns on and off when set to “On” you have a problem with the thermostat or the blower motor in the furnace.

The Air Isn’t Coming Out Warm

If the air coming out of your vents feels only barely warm to the touch, this indicates a leak somewhere in your ducts that is allowing warm air to escape. Warm air expands, and it will find its way out of any crevice it can – especially in freezing cold attics and crawlspaces. It’s important to make sure that your ducts are all in good condition in order to keep this from happening. If you cannot find or fix the problem on your own, HVAC mechanics can do so for you. Sometimes, a quick duct repair and some insulation is all you need to stay comfortable.

It is also possible that you have a two-stage furnace that provides a lesser amount of heat when it is mild outside and more heat when it is cold.  This is normal and helps maintain a more even temperature while saving money.

When your furnace struggles to maintain a constant temperature, you struggle to feel comfortable in your own home. Sometimes, the cause could be something as simple as an improperly placed or set thermostat, but in other cases, you may need to consider purchasing a whole new unit that is the right size for your living space.