Why Is My Upstairs So Hot? A Kansas City Tech Answers

June 18, 2018

Nobody likes it when the upstairs feels like a sauna in the middle of summer.

If your upstairs always feels hotter than downstairs, it’s likely because of 1 of these 3 reasons:

  1. Your attic is poorly insulated
  2. You have leaky air ducts
  3. Your home only has one thermostat—and it’s downstairs

We’ll explain each of these problems in more detail, and how you can solve them.

Want a professional to fix your hot upstairs?

Reason #1: Your attic is poorly insulated

Most rooms in a 2-story home border the attic. During hot days, when the sun beats down on the roof, the temperature of your attic rises significantly (often reaching well over 100°) since it’s an unconditioned space.

So if your attic isn’t well-insulated, then that warm air will transfer into the conditioned rooms of your home, which raises the temperature indoors and makes your AC work harder to cool your upstairs.

insulation in the attic near ductwork

Insulation in the attic


Contact an insulation company in the Kansas City area to check the insulation in your attic. If you don’t have sufficient insulation, they’ll need to add insulation to your attic.

Learn more about why you need a well-insulated attic in our article, “The 4 Most Common Home Insulation Problems in Kansas City Homes.”

Reason #2: You have leaky air ducts

Even if your attic is perfectly insulated, your upstairs will still be hot if you have leaky air ducts.

You see, over time your ductwork can develop holes or become accidentally disconnected, which means cold, conditioned air will leak into your attic/walls instead of your rooms upstairs.

leaky air ducts in attic

A leak in your ductwork means you’re wasting cold air (i.e. cold air is entering your attic instead of your upstairs rooms)


Contact a professional to inspect your ductwork for leaks. If they find any, they’ll “seal” the leaks using mastic sealant or metal tape.

And don’t be surprised if they find duct leaks: according to Energy Star, most homes lose 20%–30% of conditioned air due to leaks, holes and poorly connected ducts.  

For more information about problems caused by duct leaks, read our article, “Why Your Home’s Ductwork Could Be Leaking Money.”

Reason #3: Your home only has one thermostat—and it’s downstairs

The brain of your AC system is the thermostat: it detects the current temperature in the room and then determines when your AC needs to turn on or off to reach your desired temperature.

But since hot air naturally rises, your upstairs is always going to be hotter than your downstairs, meaning your thermostat downstairs can never detect the temperature upstairs.


You’ll need an HVAC professional to zone your home. Zoning involves adding a second thermostat upstairs to regulate the temperature there. In addition to adding another thermostat, the HVAC professional will also add a zone controller and several duct dampers.

A zone controller is a control panel that controls electronic duct dampers, which are devices installed into your ductwork that redirect air to certain parts of your home. These duct dampers allow 2 different parts of your home to remain at 2 different temperatures (represented in the image below).

AC zoning for home

A visual representation of how zoning works: 1 AC system, 2 different temperature “zones”

Note: Zoning requires a variable-speed furnace/AC blower, so you may need to upgrade your AC system before a professional can zone your home.

For more information about zoning, read our article, “How Furnace Zoning Works (And Everything Else You Need to Know About Zoning).” The article talks about furnace zoning, but the same principles apply to AC zoning.

Need help cooling the upstairs of your Kansas City home?

One of our certified techs will give you a FREE estimate on the cost to…

  • Fix air duct leaks
  • Zone your home

If you need an AC repair or installation, be sure to check out our cooling services page to see all what other services we offer.  

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