13 Easy Methods to Increase Airflow To Second Floor

Josh Mitchell

Written By

Josh Mitchell

Expert Reviewed By

Holly Curell

Last Updated On

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Key Takeaways

  • The second floor gets hot because hot air rises up and the sunlight directly heat it up (if there is no attic).
  • Cleaning your AC, regular maintenance, investing in fans and smart thermostat, insulating your home, and even paying attention to finer details such as obstruction to air vents, all can improve air flow to the second floor.
  • If nothing helps, you may have to invest in a higher BTU central AC or additional ductless mini-splits.

I've encountered countless homeowners frustrated by their air conditioning units failing to effectively cool their entire homes, particularly the challenging second floor.

Through extensive research and hands-on experience, I've discovered various methods to enhance airflow, ensuring cool, refreshing air reaches every corner of your upstairs space.

In this guide, I'll share these insights to help you transform your second floor from a sweltering retreat to a cool haven. Let’s bring comfort back to every level of your home!

Why Does Your Second Floor Get Hotter?

There are several reasons why upper floors, including the second floor, tend to get hotter even when air conditioners are operational.

Primarily, this heating up results from hot and warm air naturally rising and accumulating on upper floors.

Surprisingly, even efficient air conditioners and HVAC units can find it challenging to counteract this inherent tendency in heat distribution.

Let me detail the reasons.

Rising Hot Air

From my experience, one of the most basic yet overlooked concepts in home heating is that heat rises.

Warm air, generated from both your heating system and everyday living, naturally moves upward.[1]

This is especially noticeable on the second floor and attic spaces of homes.

Physics Note:

A reminder for the physics nerds out there; Its not the HEAT that rises up. Instead its hot air that rises up. Heat radiates in all direction not just up.

In summer, it's even more pronounced as the roof soaks up heat, making upstairs bedrooms feel like saunas.

Even homes with well-placed second-floor vents or attic fans aren't immune to this.

It's a clear reminder of nature's rules at play right in our living spaces – warm air loves to move up, leaving the top floors warmer.

TL;DR: Its basic physics but hot air always rises up hence the reason for second floor being hotter.

Hot Roof from Direct Sunlight

During my fieldwork, I've seen how direct sunlight dramatically heats roofs, particularly in the hot summer months.

This heat then radiates into the house, significantly warming the air upstairs, especially on the second floor.

It's a classic case of solar gain, where the sun's energy turns rooftops into radiators.

In houses without adequate insulation or ventilation, this effect is even more pronounced, turning the second floor into the warmest part of the home.

TL;DR: Second floor is in contact with the roof that is directly being heated up by sunlight.

Worn Duct Work or Insufficient Insulation

I've gone through many attics and crawl spaces, and I've frequently encountered worn or faulty ductwork as a key culprit in uneven home cooling.

Ducts with gaps, sealed haphazardly with duct tape or simply aging, can leak cool air before it reaches the second floor.

Moreover, insufficient insulation in these areas allows heat to seep in, countering the cool airflow.

Properly sealed and insulated ducts are crucial in ensuring that the cool air actually gets to where it's needed most.

TL;DR: A well insulated house keeps both hot air in winter and cold air in summers inside.

13 Tips on Increasing Airflow to Cool Down The Second Floor

I've learned that keeping the second floor cool is all about mastering airflow.

In this section, I'm sharing personal tips (tried and tested!) on enhancing air circulation and bringing cooler air to those upper levels.

1. Use Fan Mode to Keep Air Circulating

In my experience, a little-known trick with a big impact is using the fan mode on your air conditioner or HVAC unit.

This keeps air moving continuously, preventing stagnant hot spots. 

Coupling this with the strategic use of ceiling fans can significantly enhance the distribution of cool air.

It's a savvy move that balances the temperature without ramping up energy usage.

Just remember, effective vent placement plays a key role in optimizing this cool breeze effect throughout your home.

TL;DR: A fan helps circulate the air thus eliminating any hot spots from forming.

2. Install a Ceiling Fan

I've always found ceiling fans to be unsung heroes in keeping upstairs areas cool.

Installing them can make a world of difference in circulating air, especially during summer.

Their gentle spin helps disperse the cool air more evenly, maintaining a comfortable temperature throughout the room.[2]

On top of that, they offer a cost-effective way to maximize cooling without overworking your AC.

It's an elegant solution for those hot upper floors, ensuring your summer days and nights are as comfortable as possible.

TL;DR: Ceiling fans are particularly great for combating hot spots from forming at the ceiling height.

3. Use More Vents (In Case of Central AC)

I've noticed that homes with more vents, especially upstairs, enjoy better airflow. It's about giving cool air more entry points.

Upgrading air filters and optimizing second-floor return ducts can also propel more air where needed.

It's a straightforward tweak with significant impact, making upstairs spaces more inviting and evenly cooled.

TL;DR: For homes with central AC, increase the number of vents upstairs for added coolness.

4. Increase the Size of the Return Duct to Increase Air Flow

As mentioned, a larger return duct can be a game-changer in removing hot air and increasing second-floor cooling. This also reduces the burden on your system.

It doesn’t restrict airflow, which, in turn, enhances the overall circulation, effectively tackling those stubborn hot zones upstairs with a smoother, cooler air delivery.

TL;DR: Return duct take the hot air back to the air handler. The larger the better.

5. Keep the AC and Vents Clean

Maintaining clean air conditioning units and vents is essential for optimal cooling. Dirty filters can greatly hinder airflow, reducing efficiency, especially on upper floors.

I recall a homeowner who was puzzled about their second floor not cooling down. Upon inspection, it turned out their issue was simply a dirty unit.

Regular maintenance, including inspecting and cleaning vents, is more than a chore. It's a key step in ensuring your system efficiently delivers cool air throughout your home.[3]

TL;DR: Cleaning your AC vents is one of the easiest ways to improve airflow and cooling.

6. Get a Zoned HVAC System

I’ve noticed that installing a zoned HVAC system can revolutionize temperature control in a two-story home.

By creating different zones, such as for each floor or specific rooms, you gain precise control over airflow and cooling.

In homes with a mini-split, zoning allows for targeted cooling where it's needed most, ensuring the entire home, especially the upper levels, stays comfortably cool.

TL;DR: Zoned HVAC system allows you to perform targeted cooling. Hence you can increase the temperature and airflow for the second floor, while maintaining average setting for the first floor.

7. Add Room Sensors To Smart Thermostat System

Incorporating room sensors into a smart thermostat system is a smart move for managing upstairs temperatures.

Important Note:

You must make sure that your AC can integrate with a smart thermostat before you opt for one.

These sensors accurately read when there is a temperature change in each room, allowing the system to adjust airflow accordingly.

I've seen homes where this setup significantly improved comfort upstairs, as the thermostat dynamically responds to varying temperatures, ensuring consistent and efficient cooling throughout the house.

TL;DR: A smart thermostat is better at sensing and regulating temperatures and hence can improve airflow on all floors.

8. Invest in Ductless Mini Splits

Ductless mini splits are a game-changer for cooling, especially for homes with limited ducts leading to the top floor.

These systems provide direct cooling to specific areas, bypassing the need for extensive ducts running through lower floors.

From personal observations, they're particularly effective in older homes or additions where traditional ductwork may not reach or be as effective.

TL;DR: It your central AC is insufficient for second floor, consider investing in a ductless mini split for added airflow.

9. Get a Higher BTU AC

Opting for a higher BTU AC can be a solid solution when your current unit isn't cutting it, especially if your second floor is persistently hot.

A higher BTU rating means more cooling power, addressing issues like air leakage and efficiently countering those 'so hot' upstairs areas.

TL;DR: Perhaps your AC isn't sufficiently large for ample airflow to second floor. In this case, an AC with higher BTU is recommended.

10. Regularly Clean and Maintain AC Components

It's crucial to regularly inspect and maintain AC components, particularly the furnace and attic fan, for optimal cooling efficiency.

I've witnessed how consistent upkeep can significantly enhance airflow to the second floor while also helping to manage cooling cost.

A well-maintained system is more effective at distributing cool air evenly, especially important in those warmer upper levels, ensuring your entire home stays comfortable.

On top of that, regular maintenance ensures that your second-floor return duct and the return air system function efficiently.

TL;DR: While tedious, regular cleaning of the finer parts and their maintenance can lead to better performance and airflow on second floor.

11. Enhance Attic Ventilation and Floor-to-Floor Air Balance

In my experience, tackling the second-floor heat starts right at the top – in the attic.

Enhancing attic space ventilation is crucial to remove hot air and lower the temperature upstairs, especially during summer.

Simultaneously, adjusting airflow through upstairs vents ensures a more uniform cool from the first floor to the lower levels.

It's a balancing act that makes a world of difference, turning those sweltering upstairs rooms into comfortable retreats even in the heat of summer.

TL;DR: A well sized attic provides a buffer between second floor ceiling and direct sunlight.

12. Fine-Tune Room Airflow and Maximize Interior Layout:

In my years of fine-tuning home climates, I've learned the importance of tailoring airflow in individual rooms.

By adjusting vents to manage conditioned air, you can keep upstairs rooms cool and tackle issues of poor airflow.

At the same time, strategically arranging interior space can play a big role in boosting airflow and managing temperature changes.

Remember, sometimes it's about working smarter, not harder – a little rearrangement or vent adjustment in one room can significantly reduce the need to restrict airflow elsewhere.

TL;DR: Be mindful of the finer details like the direction of the vents, placement of objects in the rooms, and any obstruction to the airflow.

13. Utilize Closed Registers Strategy

A closed register strategy involves selectively closing certain air vents.

By inspecting your home’s layout and identifying key heat sources, you can adjust the registers, especially on the upper floor, to optimize airflow.

This method, when done correctly, can significantly enhance the overall cooling system, steering air to where it's needed most for maximum efficiency without restricting airflow and overburdening your HVAC system.

TL;DR: Closing certain vents (perhaps on the first floor) can increase the pressure of airflow to the second floor.

People Also Ask (FAQs)

How Do You Balance Temperature Between Floors?

Balancing temperature between floors involves addressing factors like insulation, ventilation, and the strategic use of thermostats.

To keep upstairs cool in summer or other hot days, ensure proper airflow through the use of fans or additional AC units.

What is the Best AC Type For a 2-Story House?

For a two-story house, ducted central air conditioning systems are often effective.

They allow for consistent cooling throughout the house, including both upstairs and downstairs.

What Size AC Do I Need In a 2-Story House?

The size of the AC needed for a two-story house depends on several factors, including the total square footage, the layout of the house, insulation quality, and the number of windows.

A professional HVAC assessment is recommended to determine the appropriate size.


  1. https://www.grc.nasa.gov/www/k-12/Summer_Training/FranktonES/Convection_main_page.html
  2. https://www.researchgate.net/publication/232397431_Studying_the_features_of_air_flow_induced_by_a_room_ceiling-fan
  3. https://www.energy.gov/energysaver/maintaining-your-air-conditioner
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Josh Mitchell


Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

My Favorite Home Appliance?

Midea U Shaped Window Air Conditioner

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