High ceilings continue to be a popular architectural design element for homes because they provide living spaces with the illusion of being larger than they actually are. They also allow space for additional skylights and windows that can flood a room with natural light. While vaulted ceilings are beautiful and do tend to lend homes an air of grandeur, there are some trade-offs involved, and among them is that rooms with vaulted ceilings are more difficult to cool and make air conditioning less efficient overall.
How High Ceilings Decrease AC Efficiency
Vaulted ceilings result in more air volume. A room with high ceilings will require a larger air conditioning system that works harder than a similar space with a standard ceiling height. The issue with more volume extends beyond just having more air to cool. It also presents additional challenges when it comes to ensuring that cooled air mixes thoroughly within the ambient space. Heat rises, and while that may sound like a positive regarding air conditioning, it usually isn’t in this scenario. The good news is that there are a number of methods through which you can offset the reduced energy efficiency.
Sizing Your Air Conditioning System
When you size an air conditioning system, you have to account for all of the space that the system will need to cool, which includes all of the air up near your vaulted ceilings. The capacity for an AC to cool a room is typically measured in BTUs or British Thermal Units. The rule of thumb is that you need 20 BTUs per square foot, which may seem simple enough. The problem with square footage in a real estate sense is that it may be inaccurate. The extra square footage added to a house by high ceilings may or may not be reflected in what a real estate agent reports as the interior space of a home. If you are unsure whether your system is sized well for your home, you will likely need a professional to assess the space you are trying to cool. They will also adjust their recommendation based on your climate zone.
Ceiling fans are among the most effective and cost-efficient ways to improve AC efficiency in rooms with vaulted ceilings. Heated air rises, but ceiling fans set in a counterclockwise direction will force that heated air back down into the room, and that helps to overcome one of the challenges mentioned earlier, which is cooled air not mixing thoroughly with the rest of the air in the room. When choosing and installing your ceiling fans, make sure that you have convenient assess to rotation adjustment because you’ll actually want those fans spinning in a clockwise direction during winter.
A common issue with vaulted ceilings is that the ductwork is designed as if the room had standard ceilings. Often, the appropriate design with a high ceiling is to have both high and low registers. When purchasing a home that is being newly constructed, you should ensure that the home is being built in that manner. Otherwise, this is an additional cost to factor in. It is possible to expand your current duct system in order to provide additional registers to better serve those vaulted rooms. You can also wait until replacing the entire system in order to make those modifications.
Another upgrade that you may want to consider is a whole-home dehumidification system. While air conditioners do dehumidify to a degree as a byproduct of cooling your home, they are not, in fact, dehumidifiers. A discrete dehumidification system reduces the workload on your AC system. It also lets you achieve your ideal relative humidity, which allows you to be comfortable at a higher temperature. These benefits are, of course, not limited to your vaulted rooms and will be felt throughout the home.
You may want to have a discussion with your local HVAC professional about your options for running your blower fan even when the AC isn’t on. While it’s usually not a good idea to run the fan 24/7, there are thermostats with a circulating feature that help keep the air evenly distributed in rooms with vaulted ceilings. This is useful when running the AC but also during months when you need neither cooling nor heating but want to keep your windows closed. For an additional investment, you can consider a mechanical ventilation system, which not only provides more circulation but gives you greater control over how much fresh air is introduced to the home. It also provides energy savings during the heating season.
There are many options when it comes to energy-efficient curtains, shades, and other window treatments. Rooms with vaulted ceilings tend to have multiple windows, and investing in window coverings can make a significant difference in the overall temperature of the room. For skylights or windows that you do not want to cover, you may want to consider low-emissivity or Low E glass, which blocks heat.
Something else to consider is insulation, and you should schedule an energy audit of your home every several years or so to determine where you are prone to energy losses. You should also pay particular attention to attics directly over vaulted ceilings. Their irregular shape makes them challenging to insulate. You may want to have your attic insulation professionally assessed and upgraded as needed for your climate.
Another common feature of vaulted rooms is a lot of lighting is needed to illuminate them well when natural sunlight is unavailable or impractical. Incandescent bulbs emit 90% to 98% of their energy as heat, which can make a significant difference even in a room if there are enough of them. Consider switching to LEDs, which may cost more upfront but won’t have to be replaced as often. Don’t worry about giving up the heat from traditional lightbulbs in winter because this method of heating your home would be inefficient.
Smart Thermostat and Smart Home
If you don’t have one yet, consider investing in a smart thermostat. The EPA estimates that the average home can save 8% on both heating and cooling with a smart thermostat. You may also want to consider integrating other smart features, such as smart shades that can automatically close to block sunlight as the temperature rises above desired levels.
Last but certainly not least, schedule seasonal maintenance for your air conditioning system in spring prior to the first use that summer. A tune-up increases energy efficiency and often pays for itself by reducing your month-to-month costs. This applies to all homes but can make an even bigger difference in homes that have vaulted ceilings.
Your Home Cooling Pros in Las Vegas
BEST Air Conditioning Plumbing Repair is proud to serve homeowners throughout Las Vegas and the neighboring communities, and our NATE-certified technicians perform a wide range of AC services, including tune-ups, repairs and installations. We also provide maintenance, repair and installation services for all manner of residential heating technologies, and our certified plumbers install water heaters, unclog drains, fix running toilets, and repair sewer lines. Call us today or contact us online if you’d like to schedule an appointment or have questions about our services and products.