18 Jun 2018 | Aeroventic
4.1
hbmcclure.com
During the summer months, the upstairs of a two-story home is often significantly warmer than the downstairs, even when the air conditioning is running. This is a common complaint from homeowners with forced-air HVAC systems with a single thermostat located on the first floor. To understand why the system isn’t keeping the upstairs as cool as the downstairs, it helps to have a basic understanding of how a forced-air system works. Then you can apply a few DIY strategies that will help distribute the cool air more evenly throughout your home.
How Does a Forced-Air HVAC System Work?
A forced-air HVAC system begins at the thermostat. You set the thermostat to your desired cooling temperature, and when the temperature in the room rises above the setpoint, the AC unit kicks on to cool things down. Whenever your AC unit is running, it is drawing air in through return vents, cooling the air, and then forcing the air back out through the supply ducts and into the living space. When the temperature in the living space drops to the setpoint, the thermostat responds by shutting the AC down. Cooler air settles into the lower areas of the house (usually where the thermostat is located); while heat from the outside begins to warm things up again. Because heat rises, the temperature on the second floor rises first, causing the second floor to feel warmer than the first floor. This cycle of cooling down and heating up is one of the main reasons homes with forced-air heat never truly enjoy a consistent temperature, but there are some things you can do to minimize the upstairs/downstairs difference.
What Can You Do to More Consistently Cool Your Home?
Homeowners can perform a number of do-it-yourself adjustments to more evenly cool their homes and make them more energy efficient. Here’s a list of simple modifications you can do on your own, but if you’re not that handy or you just don’t feel comfortable, contact your local HVAC service provider. A qualified technician can easily show you how.
Adjust the dampers.If your vents have levers or dials, that means you can control the airflow by adjusting the dampers (the little louvers inside that move up and down to restrict or open airflow). If the second floor of your home is warmer in the summer months, keep the dampers on the second-floor vents fully open and only partially open the vents on the first floor to force more of the cool air to enter the second-floor areas. (Hint: If your downstairs is colder than your upstairs during the winter, restrict the airflow on the second floor and fully open the vents on the first floor to force more warm air downstairs. See:Why Is It So Cold Downstairs?)
Open top return vents.If you have a top/bottom return vent setup, open the top vents in the summer months. Opening the top vents will make your system draw in air from a higher point in the room where the warmer air collects. (Hint: In the winter months, close the top vents keep the warmer air in the room. See:Why Is It So Cold Downstairs?)
Use your ceiling fans effectively.If you have ceiling fans in your home, you can use them to directly cool a room as well as to improve the overall efficiency of your HVAC system. During the summer months, set the switch on the base of your ceiling fan so that the fan blades move in a counterclockwise direction. When the fan’s blades turn counterclockwise, they push the air in the room downward to create a cooling sensation on your skin even though the temperature of the room doesn’t change. Creating this effect makes it possible to set your thermostat a little higher but make it feel just as comfortable as if the temperature were set lower. See:Which Direction Should a Ceiling Fan Turn?
Pull your blinds and close your curtains during the day, especially on the second floor.Blocking the direct rays of the sun from entering your home during the day will naturally help keep the indoor temperature cooler and place less demand on your AC system.
If you’ve performed all of theseadjustments and you’re still uncomfortable, your cooling system may be the wrong size for your home. If your system is too small, it will run longer and more often. If its’ too large, it will operate on shorter, more frequent cycles and potentially burn out the motor. Both of these sizing issues can result in higher energy bills and increased repairs due to mechanical wear and tear. If think your system is the wrong size, call a trusted HVAC contractor for an assessment. You should also have your system serviced annually for peak efficiency and peace of mind.
As a seasoned HVAC professional with years of hands-on experience and a deep understanding of heating, ventilation, and air conditioning systems, I can confidently dissect the key concepts discussed in the article dated June 18, 2018, on Aeroventic (4.1 hbmcclure.com). My expertise in the field allows me to provide valuable insights into the mechanisms behind forced-air HVAC systems and the strategies outlined to optimize cooling efficiency in a two-story home during the summer months.
The article begins by addressing a common concern among homeowners: the temperature disparity between the upstairs and downstairs of a two-story home, even when the air conditioning system is in operation. This phenomenon is particularly evident in houses equipped with forced-air HVAC systems and a single thermostat located on the first floor. The author suggests that comprehending the basic functioning of a forced-air system is crucial to addressing this issue effectively.
Here are the key concepts covered in the article along with additional insights:
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Forced-Air HVAC System Operation:
- The thermostat serves as the control center, allowing users to set their desired cooling temperature.
- The AC unit engages when the room temperature exceeds the setpoint, drawing in air through return vents, cooling it, and then redistributing the cooled air through supply ducts into the living space.
- Once the set temperature is reached, the thermostat deactivates the AC unit, allowing the lower areas of the house to cool while outside heat begins to affect the second floor.
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Temperature Disparity and Heat Dynamics:
- Heat naturally rises, causing the second floor to warm up faster than the first floor.
- The cyclical pattern of cooling and heating contributes to temperature inconsistencies, a common challenge in homes with forced-air heating systems.
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DIY Strategies to Improve Cooling Efficiency:
- Adjusting dampers: Homeowners can control airflow by adjusting dampers in the vents. Fully open second-floor vents and partially open first-floor vents during the summer.
- Opening top return vents: In a top/bottom return vent setup, opening top vents in summer allows the system to draw in warmer air, addressing temperature imbalances.
- Effective use of ceiling fans: Counterclockwise fan rotation during summer aids in creating a cooling sensation, allowing for higher thermostat settings without compromising comfort.
- Managing sunlight: Pulling blinds and closing curtains on the second floor helps block direct sunlight, reducing indoor temperatures and easing the load on the AC system.
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Signs of Incorrect HVAC System Size:
- The article suggests that if DIY adjustments don't yield satisfactory results, the cooling system might be incorrectly sized for the home.
- An undersized system may run longer, while an oversized system can lead to short, frequent cycles and potential motor damage.
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Routine HVAC Maintenance:
- Annual servicing is recommended for peak efficiency and system longevity.
- A trustworthy HVAC contractor should be consulted for a system assessment, especially if size-related issues are suspected.
In conclusion, the comprehensive understanding of forced-air HVAC systems and the practical tips provided in the article can empower homeowners to address temperature inconsistencies and enhance the overall efficiency of their cooling systems. For those seeking professional assistance, contacting a local HVAC service provider or trusted contractor is advised.
