Why Is The Second Floor Usually Hotter Than The First Floor?

Jessica Stone
by Jessica Stone

If you live in a multiple story home, you may have found yourself questioning why your second floor is so much hotter than the first. Unfortunately, a warmer second floor may not be noticeable until the summer months when the heat really starts coming in. And when it happens, you’ll start to feel extremely uncomfortable.

This common problem often results in homeowners cranking up their air conditioning and still unable to achieve the comfortable temperature they desire. We were taught in grade school that warm air rises, but they’re actually may be quite a bit more to why you’re experiencing this heat issue in your home.

Heat rises and cold air generally hangs low in 2-story homes, and that is why the 2nd floor feels hotter. Poor ductwork or an outdated air conditioner can also make your second floor feel hot. Check your attic’s insulation if the top floor of your house is too hot to make sure it was properly installed.

We’ll examine the various possible causes in further detail and provide you with some tips for keeping your second floor just as cool as your first floor.

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Faulty Ductwork

The most common cause of a hotter second floor in the home involves the ductwork. Your central heating and air systems involve the generation of cold air at the air conditioner and hot air at your furnace. After the air is produced, the hot or cool air is then pushed throughout the home using a series of ducts. Ducts are simply the square (or round, in some cases) metal passages you see running through your walls and ceiling.

The further that the air has to travel from its generation point to the various areas throughout your home, the more it is affected and changed by the surrounding temperatures. If the ducts were improperly installed, there isn’t enough ductwork to reach the second floor, or the air is escaping through a gap or leak, your HVAC will be forced to work harder in order to properly cool your home.

Leaking Problems

Additionally, animals and other critters can chew through your ductwork, causing major leaking problems in your HVAC system. As your air conditioner is working hard to cool your home, energy costs go up, and your second floor becomes hotter and hotter as the system fails.

If you think this may be the cause of your second floor being significantly warmer than your first floor, contact an HVAC professional to perform an air quality inspection and help you detect any possible leaks within your ductwork.

Your Air Conditioner May Be Too Old

Although this may seem like an apparent cause, your air conditioner can be faulty in more ways than one. It may be due for a filter change, or it could be too old and time for a replacement.

The average life expectancy of an air conditioner is 15 years, and if yours is approaching this age it may just be too old to handle the job properly. An aging air conditioner may cause a substantial temperature difference between your floors.

If you have not been keeping up with basic air conditioner maintenance, this can potentially cause it to show signs of age in 10 years or fewer. Whereas, an air conditioner that has been well maintained could last you 20 or 25 years, well beyond the average life span. But, keep in mind that even a well-maintained system will ultimately lose efficiency, meaning that it will be less effective in cooling and circulating air.

If you think that an air conditioner that is too old is the culprit, consider having it replaced to properly service the upper levels of your home.

Single-Zone Cooling

We all know and understand the fact that physics tells us that heat rises. With a single-zone cooling system and your HVAC unit located on the first floor of your home, the system has to work harder to cool your second floor. It has to efficiently push hot air out as cooler air is entering the room.

Even with a well-maintained, correctly sized air conditioner, the second story of your home is almost always going to be warmer than the first floor. If you have single-zone cooling and want to have more consistent temperatures among the floors in your home, consider splitting it into multiple zones.

A Poorly Insulated Attic

There’s no doubting the fact that attics provide excellent storage space; however, there’s a reason that you don’t live in that area of your home. Unless you’ve gone to extensive lengths to have your attic exceptionally insulated, even the best-insulated attics will still be 10-20 degrees hotter than the temperature outside in the summer months.

For example, on a hot 95-degree summer day, expect for your attic to reach upwards of 115 degrees. However, if your attic is poorly insulated, it can actually get to a scorching 150 degrees! This can undeniably cause a disaster when it comes to your air conditioner’s capability to cool the second floor of your home properly.

Unless you’ve installed roofing materials that deflect heat, most shingles absorb heat, causing it to seep through the wood beams and into the attic space itself. Asphalt shingles are some of the worst offenders for this. Without adequate insulation, the heat will make its way right into your second story, making it incredibly difficult for your HVAC system to cool it effectively.

Tips To Cool Down Your Second Floor

With a better understanding of what may be causing your second story to be hotter than the ground floor in your home, here are some tips you can follow to cool it down:

  • Install ceiling fans to help better distribute the air on your second floor. This can be especially effective in warmer areas where air movement may help it feel cooler even if the temperature doesn’t physically change.
  • Install a multiple zoning system to balance out the temperatures between levels in your home. Like previously mentioned, if you have a single-zoning system, it may not be doing you any favors. Instead, splitting it into multiple zones will allow for a separate thermostat on your second floor that operates independently from the lower level. This is a very effective way to combat the rise of warm air and address comfort issues in rooms that are normally difficult to cool down.
  • Properly insulate and ventilate your attic to lessen the amount of heat reaching your second floor. Effective insulation will keep the heat from outside from seeping through your roof, and an attic fan can help circulate the air.
  • Insulate windows to keep heat from seeping in. Seal all cracks, gaps, and holes in your windows to prevent any seepage. This is especially helpful for when the heat in the summer is at its strongest. Or, consider upgrading to double pane windows, a more energy-efficient option.
  • Change your air filters. This is a simple step that will go a long way. They should be maintained often as dirty air filters can block the flow of cool air throughout your home.
  • Adjust the fan setting on your thermometer from “auto” to “on.” Doing this will allow the blower fan to run constantly and produce a more consistent mix of air throughout your home. Also, running the fan does not use a lot of energy and may actually reduce energy usage since your HVAC system won’t have to cycle as frequently.
  • Install a ductless mini-split unit for problem rooms. If you find the issue isn’t your entire second floor but rather one specific area, consider installing a ductless mini-split system. They work independently of your HVAC system and are very energy-efficient.

Setting Your Thermostat For Your Two Story Home

While setting your thermostat may seem simple, there is actually a bit of an art to it. What you’ll want to do during the summer time is set your second floor to the temperature that you want inside of your home. Then, the first floor will need to be two degrees warmer than the second floor.

By doing this, you’re giving the upstairs some help when it comes to cooling down since the hot air escapes to the second floor. Now, the bottom floor won’t need to work as hard to push the cold air up to the second floor. This will result in saving some money. Also, now you won’t have the issue of your upstairs being too hot, but your downstairs being too cold.

What About A 3 Story House?

The rule of thumb is setting your highest floor to your actual desired temperature, and then each floor beneath that will be two degrees warmer. So, for example, in a four-story house, you will set your 4th floor to 65 degrees and the lower three levels to 67 degrees. Or whatever your desired temperature is.

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Wrapping It Up

With summer taking place in most areas of the world right now, you may be experiencing the issue of your second story being hotter than your first floor.

Whether this is caused by a poorly insulated attic, faulty ductwork or an air conditioning that is too old, you should now have the proper knowledge and tools to help achieve consistent cooling throughout your home.

Jessica Stone
Jessica Stone

Jessica considers herself a home improvement and design enthusiast. She grew up surrounded by constant home improvement projects and owes most of what she knows to helping her dad renovate her childhood home. Being a Los Angeles resident, Jessica spends a lot of her time looking for her next DIY project and sharing her love for home design.

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