Help! Why Is My House Hot Upstairs and Cold Downstairs?
Key takeaways:
• Hot air rises, so your upstairs can be naturally hotter than downstairs.
• A poorly insulated attic and leaky ductwork can make the problem worse.
• A zoned HVAC system can solve the problem.
By Anne Fonda
It’s summer, your air conditioner’s on full blast and every room downstairs feels cool and refreshing. Your second floor, though? It feels like you’re trekking through the Sahara.
Sound familiar?
Scores of homeowners experience the same frustration during the hottest months of the year when their two-story homes get hot and humid upstairs while staying cool and airy downstairs.
The good news is that you don’t have to accept a hot upstairs and cold downstairs as a fact of life. Learn why this keeps happening and what you can do to change it.
Why is upstairs so much hotter?
- Heat rises – Blame physics: hot air rises while cold air sinks. That means your upstairs typically gets hotter than your lower levels, even if your central air conditioner or heat pump is working in overdrive.
- Your roof’s hot, too – Unless you have shady tree cover, your roof absorbs a ton of heat from the sun. That hot air seeps into your attic before settling onto your top floor. If you don’t have attic space to buffer the heat or your roof isn’t well-insulated, you’ll automatically feel hotter upstairs.
- Faulty ductwork – Ductwork transports the cool air from your HVAC system and distributes it throughout your home. If your ducts are old, were installed poorly, or leak, then your air conditioning system may struggle to evenly cool your home.
- You may be using a single-zone system – Standard HVAC systems are designed to heat and cool your entire home to one temperature. They can work great for single-story homes, but can leave something to be desired in a multi-story home.
- Your air conditioner (or heat pump) might be old and inefficient – Most central air conditioners and heat pumps last up to 15 years. If yours used to be OK but now isn’t sufficiently cooling your home, it could simply be nearing the end of its lifespan. Consider replacing your old unit. A newer, more energy-efficient model could more adequately cool your home, help establish an equilibrium in temperature between floors, and save you in utility costs.
Contact a dealer
From finding the right HVAC system to maintaining it, a dealer is your best resource.
Get your questions answered every step of the way.
How to make upstairs cooler
#1: Block the sun
Close your blinds and shades to block excessive light and ultraviolet rays. You can even try heat blocking shades or UV-blocking film. Be sure to seal all cracks, holes and gaps around windows to prevent air leaks. And you may want to consider upgrading to more energy-efficient double pane windows.
#2: Seal and insulate
Insulation plays a crucial role in keeping your home comfortable and energy efficient (it can help lower your energy bills). Try adding extra insulation to your roof or attic. Seal gaps in your attic and around doors and windows. Weatherizing your home can help decrease heat gain and heat loss.
An attic fan can help push hot air out of your attic and limit the amount of hot air lingering on your second floor.
#3: Repair or seal leaking ductwork
If leaky ductwork is the source of your cooling issues, contact an HVAC professional to identify the areas where the leaks are happening. An HVAC technician may cover them with insulation or use an aluminum foil tape or mastic sealant to cover gaps. They may also suggest internally sealing ducts that are hidden in the walls and ceiling. Lastly, they may suggest replacing ductwork that has badly deteriorated.
#4: Reduce your use of lights and appliances
Avoid creating more heat upstairs. Keep your lights off or dimmed. Cut back on appliances that generate heat like dishwashers, ovens, and stoves, especially in the afternoon and evening. Consider grilling out or using an air fryer.
#5: Change HVAC air filters
You should change your HVAC air filter every 30-90 days year-round, not just in the summer. A dirty air filter can restrict the flow of cool air and force your HVAC system to work harder. Check and change your air filters to ensure airflow isn’t hindered as it moves through your home.
“How often you replace your air filter will depend on filter type, usage, and environmental factors. To be on the safe side, plan on changing a standard 1-inch filter at least every 90 days. You may want to change it every 30 days if you have high system usage, allergies, or pets.”
- Sean Goddard, Product Manager, Coils & Indoor Air Quality
#6: Adjust the fan setting on your thermostat
Switch it from “auto” to “on,” in the summer so the blower fan runs constantly and creates a more even mix of air throughout your home. Running your fan doesn’t use a lot of energy but running it continuously can increase wear and tear.
#7: Use ceiling fans and floor fans
Your ceiling and floor fans can help circulate the cold air that may be lingering near the floor. Fans create a wind chill effect, making you feel cooler. Just remember that fans cool people, not rooms. So, if you’re planning to be out of the room for a while, turn the fan off to limit energy use.
#8: Check for HVAC dampers
We don’t recommend closing vents downstairs to cool the upstairs. This can restrict airflow to your system, causing it to work harder, and potentially resulting in a frozen evaporator coil.
Instead, you may have a manual HVAC damper system and not even know it. Check the exposed ductwork in your basement or attic and look for a toggle switch. It may even be marked with “Summer” and “Winter” with directional arrows. If you find this, move it to the appropriate setting for each season.
#9: Upgrade to a zoned HVAC system
If you don’t have manual dampers, consider installing motorized mechanical dampers in a zoned HVAC system.
“An HVAC zoning system divides your home into multiple zones, and they are controlled by a smart thermostat and an HVAC zone controller. This allows you to set each zone to the ideal temperature (and humidity) for you, instead of having to try to heat or cool the entire home to just one temperature.”
David Lothe, Product Manager, Communications and Accessories, System Controls
A zoned system is a smart HVAC solution that lets you remotely manage your home’s climate, set a schedule based on your home’s unique temperature patterns and monitor and control your zoning system through any web-enabled device. HVAC zoning can also prevent your upstairs from getting too hot in the winter.
#10: Consider adding an extra HVAC system
If you’ve tried a little bit of everything and your upstairs still won’t cool down, your home may be too large for your current HVAC system. Talk to your local Trane dealer about upgrading to a larger capacity HVAC system or adding a second system for the upstairs.
Get help now
There’s no denying that a hot and humid upstairs is uncomfortable, maybe even unbearable. If you’re worried that your heat pump or air conditioner isn’t working properly, call your local Trane HVAC expert for help.
They can inspect your current system and see if it just needs a tuneup or ductwork repair. They can also help you decide if climate zones or an additional system could make your home more comfortable.
Anne Fonda, Content Writer
A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.
She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism.
When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.
Related Articles
