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Why Are Some Rooms in My House Hotter (or Colder) Than Others?

Have you noticed that some of the rooms in your home are always hotter or colder than others no matter what you set your thermostat to?


First, check for these common problems:

  • Air duct issues—If you have any kinked or crushed supply ducts, certain rooms won’t get enough air. Also leaky ducts cause a host of problems, including uneven temperatures. Here’s how to tell if your ducts are leaking.

If it’s not one of the problems above, the next likely cause is an unbalanced air conditioning and heating system. You’ll need an AC company to balance it.

What is air balancing?

Air balancing is the process of adjusting the amount of cooled and heated air each room in your home gets.

In a perfectly balanced system, every room in the home would reach the same temperature at exactly the same time. A home with very different temperatures in different rooms is said to have an unbalanced system.

6 causes of an unbalanced system (and how to fix them)

Many different things can cause your air conditioning and heating system to be unbalanced.

When an air conditioning system is installed, larger ducts and more supply vents are used to get larger volumes of air into the rooms that need it.

Proper duct installation gets your system pretty close to balanced. Dampers are then used to fine tune the airflow and provide even temperatures throughout your house.

Dampers are valves that let you accurately adjust the amount of air going to each room or part of the house. They are installed on the main ducts near the inside unit of the air conditioner (usually in the attic or a closet).

But many things can disrupt this balance. Here are a few of the most common problems and how to fix them:

1) More than one level

Multiple levels are difficult to balance properly because you must account for heat rising and long runs of ducts needed to get air into all the rooms.

Solutions: The best solution to this problem is usually a zoned air conditioning system. Zoning breaks up your home into different areas. Each zone has a thermostat or temperature sensor that automatically controls dampers in your ducts.

You can use zoning to even out the temperature in your home or to set different temperatures for different rooms. Learn more about zoning.

2) Uninsulated or long runs of ducts

Cool air traveling through ductwork in unconditioned areas (like your attic) gains heat. Therefore, long runs of ducts and uninsulated ducts will leave rooms farther away from an AC much warmer.

Conversely, rooms closer to the AC will be much cooler.

Solutions: Fixing this problem could be as simple as adding insulation to your ducts. Or it could be as complex as restructuring all your home’s ductwork to more evenly distribute the air throughout your home.

3) Inadequate return vents

Many large homes have only a single return vent, which can’t adequately suck in the warm air from far away rooms. So you have lots of cool air mixing with warmer air.

Solutions: Try leaving the doors to all of your rooms open. This can often help with return airflow. Otherwise, you may need to add more return ducts to your home.

4) Over or undersized system

An AC system that’s too large (oversized) will shut off too quickly, leaving some rooms too warm or cold. A system that’s too small (undersized) may never actually be able to cool the entire house properly.

Solutions: If your AC system is too large, try using fans to circulate the cool air to the warm rooms in your home. If your AC is too small, you may need an additional system (or a newer, bigger system if your current system is ready for retirement).

5) Room use

How you’re using the room might have unbalanced your system. For example, your home office may be warmer because it contains a server, computers and other electronics that produce heat.

Solutions: The fix really depends on what the problem is. But many of these problems can be solved by an air conditioning company adjusting the airflow to your rooms using dampers in the air ducts.

6) Home additions/renovations

A remodel done by you or a previous homeowner may have upset your AC system’s balance, especially if walls were added or removed.

Solutions: If the problem is minor, you may be able to fix it by having an AC company adjust the dampers in your ducts. Otherwise, you may need to run additional ducts. In the case of some home additions, you may need a second air conditioner.

We help you get rid of hot/cold spots in your home

Contact Cool Today, and we’ll help find and fix the source of your hot and cold rooms.

We serve Sarasota, Florida and the surrounding areas like Bradenton, Tampa and Port Charlotte.