Owning a home with high ceilings is something many people dream about. There is no doubt that high ceilings are beautiful and will increase both the value and aesthetic appeal of your home. One thing that many people don’t consider about high ceilings is the impact they can have on the amount of energy that is needed to keep the home cool. High ceilings also have a direct effect on your heating system, as well. Let’s take a closer look at how ceiling height impacts HVAC efficiency and what you can do to lessen this effect.
Higher Ceilings Equal Increased Air Volume
The size of your air conditioner is directly related to how much energy it uses, and the same is also true for your furnace. In turn, the size of your home dictates how large your A/C and furnace need to be. In most cases, you use the building’s total square footage to calculate what size of HVAC equipment is needed. However, a home with vaulted ceilings will generally require a larger unit than a home of the same size with standard-height ceilings.
When your ceilings are higher, there is a greater volume of air that needs to be cooled or heated. This means that your HVAC units will need to produce more BTUs (British Thermal Units) to effectively cool all of the additional air. As a result, you’ll end up paying more in energy costs to run the larger unit, and it will also cost you more upfront whenever it comes time to replace your old A/C or furnace.
If your A/C doesn’t have sufficient capacity, it will end up running almost constantly to maintain a consistent temperature. Major issues can also occur if your A/C is oversized. In this case, it will end up turning on and off much more frequently. This places added stress on the system and increases wear and tear on its components, which can lead to more frequent, and potentially more costly, repairs and an overall shorter lifespan.
Constantly turning on and off also causes increased energy use, as your A/C condenser and blower fan typically use up to three times more energy in the few seconds that they start than they do when just running. So, if your A/C starts up four times an hour for 10 minutes each, it will use much more energy than it would if it started only once per hour for 30 minutes.
Less Air Circulation and Longer Run Times
One of the biggest issues with high ceilings is that they make it much more difficult for your HVAC system to properly circulate air. This issue is most pronounced during the winter as all of the hot air from your heating system will quickly rise and get trapped at the ceiling. The result is that your furnace needs to run much more often to raise the overall temperature inside the home.
This issue affects your air conditioning during the summer as well. Even though the cool air from your A/C will always settle near the floor, your system will still need to run longer and more frequently to overcome the poor air circulation caused by your high ceilings.
For your A/C to work properly, it needs to continuously draw in hot air. This is much more difficult when all of the hot air remains trapped near the ceiling far away from your return air vents. The lack of circulation means that your A/C won’t absorb heat nearly as quickly as it would in a home with standard-height ceilings. This reduces the system’s efficiency and means the A/C and blower fan will need to work harder and run longer to effectively cool your home.
How to Lessen the Impact High Ceilings Have on HVAC Efficiency
There are several different ways that you can help to overcome the reduced HVAC efficiency caused by high ceilings. One of the easiest and best options is to use your ceiling fans to help better circulate air throughout the room. During the summer, you should set your ceiling fans to spin counterclockwise. This pushes the hot air near the ceiling downward, which can greatly help to improve air circulation.
By pushing air downward, ceiling fans also create a breeze that helps you feel cooler. The EPA states that this cooling effect can enable you to set your thermostat to up to four degrees higher without any noticeable impact on your comfort. By improving air circulation and helping you feel cooler, ceiling fans can reduce the need for your A/C to run as frequently and thus help lower your energy costs.
The EPA also estimates that using ceiling fans during the winter can reduce your heating costs by approximately 15%. In the winter, you want your ceiling fans spinning clockwise on the lowest speed setting. This creates more circulation up near the ceiling, which helps to better distribute the hot air from your furnace throughout the room. Again, this effect allows you to set your thermostat a few degrees cooler than you normally would without impacting your comfort.
The location of your supply and return registers is also important when you have high ceilings. Your supply vents should always be as close to the floor as possible as this will help to improve the efficiency and effectiveness of your cooling and heating systems. In homes with high ceilings, your return air vents should always be high up on the walls close to the ceiling. This greatly increases the efficiency of your air conditioning since the system will draw in much hotter air than it would if the return registers were closer to the floor.
Another great option is to install a whole-house fan in your attic. Attics trap a huge amount of heat during the daytime. As the outdoor temperatures start to cool in the evening, much of this air begins to penetrate down into the building and will quickly raise the temperature. This is why most homes are at their hottest in the late afternoon/early evening.
Whole-house fans work by drawing air in from the rest of the home and venting it out through the attic. This creates a through-draft that will quickly reduce the temperature in the attic and the rest of the house. However, whole-house fans work properly only when you have at least a few windows open. Once the sun goes down and the temperature outside drops, you can turn on the fan and open your windows. This will help to draw cool air in and can lower the temperature inside much quicker than your A/C, which results in improved comfort and lower energy costs.
Professional A/C and Heating Services
If you’re looking for ways to overcome the effects your high ceilings have on HVAC efficiency, the experts at Jerry Kelly Heating & Air Conditioning in St. Peters are here to help. Our certified technicians can inspect your A/C and furnace to ensure that they are the correct size and functioning at their peak level of efficiency. We can also repair any issues that could be reducing the effectiveness of your HVAC system. Our team has years of experience installing, repairing and maintaining all types of residential HVAC equipment, including central air conditioners, furnaces, ductless mini-splits and heat pumps. If you have any questions about ceiling height and A/C efficiency or need any HVAC service, call us today.