We really love our beautiful vaulted ceilings here in Southwest Florida. There’s something very elegant about the spaciousness a soaring ceiling provides by opening up a room. However, a high ceiling that is four-feet or more above the standard 8-foot ceiling height alters the air-flow dynamics in your home, which in turn affects the performance and efficiency of your HVAC system.
It’s a simple fact of physics, hot air rises and high ceilings trap rising warm air. The increased amount of space between the ceiling and the floor makes circulating cold air challenging, because there’s more room for hot air to rise, and this causes a stratification or a tendency for pockets of hot and cold air to develop. So a coolness deficit can occur in the rooms with high ceilings. Not exactly what you want as we go into the hot summer months here. Of course, we all want to cool our homes as inexpensively as possible and without the waste. None of us needs skyrocketing energy bills. There are ways to cool the air efficiently and keep your energy bills low, even if you have high ceilings, so let’s look at some ways to do that.
One of the most important things you can do to compensate for elevated ceilings is to make sure your house has the right sized HVAC system. Air conditioning systems that are either oversized or undersized can leave you with serious energy inefficiency. At Wayne Martin & Son, our technicians will collect meticulous information about your home before recommending an HVAC system for it. We will look at square footage, ceiling heights, number of occupants in the home, number and size of the windows throughout the home and many other factors to ensure we choose the right BTU capacity. Air conditioner cooling performance is rated by BTU capacity, which is based on the square footage of the rooms to be cooled. If one or more of your rooms has high ceilings, that must be taken into account when determining BTU capacity or it may not produce sufficient cooling power to accommodate the larger air volume in those rooms. Because a room with a high ceiling contains substantially more air volume than a standard room, an A/C unit with greater BTU capacity will likely be required to provide adequate cooling performance. If the air conditioner BTU capacity is too high, the unit will cycle off too frequently and the room will not remain cool. An air conditioning unit one or two BTUs higher than what is recommended for your room based on square footage alone will cool the room more efficiently.
Location, Location, Location
Believe it or not, where your air conditioner condenser unit is located outside your house makes a difference in its efficiency. You want to be sure it is installed on the shadiest side of your home. Having it in the shade can ensure using up to 10% less energy than if it is placed in a sunny location. Shade, whether it’s shaded by the house itself or shaded by a lovely big tree, helps keep the unit running cooler. Just be sure to keep the tree’s branches pruned several feet from the equipment, and don’t make the mistake of planting shrubs too close, as shrubs stop the flow of air around the equipment.
Ductwork design must take into consideration the height of the ceilings in your home. This cannot be a cookie-cutter approach. Hot air rises, and as such in the summer the air conditioner will have to labor harder to cool that room. In rooms with high ceilings, the ducts should be lower to the ground, as there is no reason to spend energy climate controlling spaces that people can’t reach without a ladder. Or another idea is to incorporate low- and high-return air registers into the high-ceiling room. In the summer, you can shut down the lower return with a magnetic cover or a damper, which will allow the high return to remove heat from the ceiling, facilitating better cool-air flow in the room. In the winter you would do the opposite, to allow the warmer air to come down into the room when you need it.
High ceilings trap rising warm air, causing a problem called air stratification, where patches of hot and cold air develop in a building, leaving the air conditioning running at a high level while it still feels hot in the room. The amount of space between the ceiling and floor makes circulating cold air a challenge. Because there is more room for hot air to rise, there is a greater tendency for “pockets” of hot and cold air to develop in these types of buildings. One of the best ways to get the air flow moving in a high ceiling room is to have ceiling fans installed. These fans can be used in tandem with your air conditioning to move the cooler air around so that it is more evenly dispersed. In the summer run the fan’s blades counter-clockwise to stir up a breeze that makes you feel cooler. In the winter you can reverse the fan’s rotation to clockwise to remove heat from the ceiling and push it downward to keep the room warmer. For these higher ceiling rooms, add an extension rod so the fan is not so close to the ceiling. It will do the most good at 8-10 feet above floor level. Also, look into fans that have wide paddles as those move air around more efficiently.
Whether you have vaulted ceilings or standard ceilings, if you are looking for a new HVAC install or to help with your current air conditioner’s efficiency, give us a call at 239-462-4068. #floridaairconditioning #SWFLHVAC