Why Some Rooms Are Colder Than Others and How to Fix It

Amy Pawlukiewicz
Written by Amy Pawlukiewicz
Updated January 18, 2022
woman in a blanket drinking coffee
Photo: Charday Penn / E+ / Getty Images


  • Dirt on the air filter or in your ducts can lead to temperature disturbances.

  • An HVAC inspection, which costs $70 to $100, can help you determine the problem.

  • A zoned system may be beneficial to balance your temperatures.

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It’s wintertime, and you’re walking through your house, enjoying the warm heat pumping through it while you gaze out the window at the snow falling softly. Then you get to the next room and suddenly you’re freezing. What causes these temperature differences? Here’s why some rooms are colder than others, and how to fix it.

Dirty Air Filter

A dirty furnace filter is a common cause of temperature differences from room to room in your home. Fortunately, it’s also one of the most easily fixed problems. If your air filter is dirty, its efficiency is reduced, causing uneven airflow, which causes colder rooms. 

Plus, a dirty air filter means that dust and other particles are getting into your air, which can cause health problems, especially if you have allergy or asthma sufferers in your family. Changing your air filter monthly can prevent the filter from getting dirt and dust buildup, allowing free airflow and keeping your home evenly heated.

Dirty or Blocked Ductwork

Many homeowners don’t realize this, but you should have your HVAC system inspected at least once a year to make sure that your ducts are clean and free of debris. Dust, mold, insects, pests, and other nasty things can take root in your ducts, blocking the airflow and sending contaminated air into your home. 

Maintaining clean ductwork is an easy fix, so have a local HVAC professional come to your home yearly to inspect and clean your ducts. HVAC inspections cost around $70 to $100 on average, which is a good deal to have your system stay in working order. 

Plus, having your ducts cleaned will extend the life of your HVAC system and help it run more efficiently, saving you on energy bills in the long run.

Blocked or Closed Air Vents

There’s a myth that shutting the air vents in rooms you don’t use very often can save you money on heating and cooling costs. Unfortunately, your heating system doesn’t work that way—closing vents doesn’t change the amount of heat your HVAC system produces, and it can actually cause your system to work harder.

Large furniture sitting on top of or blocking vents can also cause dysfunction in your system. Do an audit of the vents in your home, open any closed air vents, and be sure to move furniture to give the vents room to blow air into the rooms.

Inadequate Insulation

A professional installing fibreglass insulation in a wall
Photo: Authentic Images / E+ / Getty Images

Some homes, especially older homes in warm climates, don’t have enough insulation to keep heat and air conditioning from escaping. If your home has a newer addition, this may be especially noticeable since the addition likely has better insulation than the older portion. 

Homes with vaulted ceilings are especially susceptible to insulation problems because there is no attic space to house ceiling insulation. Some power companies offer a free home energy audit, and there are even federal tax credits available to add insulation and upgrade the energy efficiency of your home.

Escaping Air 

Older windows, gaps under and around door frames, and even small spaces between outlets and walls can allow major air leaks. Sealing your windows in the winter, using door stoppers, and spraying caulk or foam into gaps can help stop the warm air from leaking out and the cold air from getting in. 

According to the Department of Energy, inefficient windows are responsible for 25% to 30% of heat loss homes experience during the winter. If you’re ready to upgrade your windows, dual-pane glass can be a huge energy saver, and triple-pane glass is even better.

Poorly Installed or Unbalanced Ductwork

Ductwork plays a huge role in how heat is distributed through your home. Balancing ductwork takes finesse, and if your system doesn’t have the appropriately sized ducts carrying air to certain rooms or if the ductwork was installed badly, you’ll experience temperature problems in your home. 

Even if you have a new furnace, your pro may not have replaced the ductwork when they did the installation. The cost to replace ductwork varies greatly depending on your home needs, so consult your HVAC pro to see if that’s the problem and get a quote.

Incorrectly Sized System

If one room is colder (or warmer) than the others, it’s possible that your furnace system is not the proper size for your home. This usually happens when an addition is built, but the HVAC system isn’t upgraded to fit the new square footage.

Your home might benefit from what’s called HVAC zoning, where your home is divided into zones with different thermostats for each zone. The thermostats are individually controlled, so you have total control over your home and can set different temperatures for different zones.

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