A whole-house fan can be a great addition to any home as the unit will improve indoor air quality and can also be used to help keep your home cool at times. Whole-house fans are energy efficient and also extremely effective at circulating air through the home and drawing heat outside. However, these units do have their limitations and are really only effective when used at certain times. To understand why this is, it is necessary to know a bit more about exactly what a whole-house fan is and how it works.
How Whole-House Fans Work
Whole-house fans are installed in the attic, and the unit is connected to a ceiling vent located in a central area of the home such as a living room or main hallway. The fan works to draw air in from outside and also pull the hot, stale air inside the home up through the vent. The air is then pumped into the attic where it then flows outside through the attic vents.
In order for the fan to draw fresh air in from outside, it is necessary to have at least a few windows partially open. Running the fan with the windows open is essential for safety reasons and also for the fan to work properly. If the fan were to run without any open windows, it could create a backdraft that draws carbon monoxide and other harmful combustion fumes from a gas water heater or any other gas-burning appliance into the living areas.
Running a whole-house fan without any windows or doors open can also cause the fan’s motor to quickly start overheating and potentially lead to it burning out. The fan also won’t work effectively if no windows are open since it will have no way to pull air in from outside.
Whole-house fans aren’t really designed to be a permanent option for cooling or improving indoor air quality. Instead, they are only meant to be used at times when the outdoor temperature is the same or lower than the desired indoor temperature. This means that they should mostly only be used in the mornings and evenings or in the early spring and late fall when the weather is cooler. If you were to use the fan during the hottest part of the day, it would quickly cause the temperature inside to rise since the fan would constantly pull hot, humid air in from outside.
Whole-house fans are most effective when you only have a few windows partially opened by a couple of inches. Most manufacturers recommend turning the fan on in the early evening once the temperature has started to drop and opening the windows in the living room, kitchen or wherever you’re spending most of your time. Once those areas are cooled, you can then start opening a few windows in other parts of the home. When you go to bed, you can then close the other windows and open your bedroom windows a crack to create a breeze to help you stay cool as you sleep.
Pros and Cons of Using a Whole-House Fan
As long as the outdoor air temperature is close to the same as your desired indoor temperature, a whole-house fan can be an extremely effective option for cooling your home. In most cases, the fan will use less than a quarter of the electricity that your air conditioning system would. This makes it a great option for reducing your energy bills while still ensuring your home stays cool and comfortable. Even if the outdoor temperature is slightly above your desired indoor temperature, the fan can still be effective as it will create a cooling breeze and draw out the heat that has accumulated inside.
The issue in warmer places like Texas is that the temperatures from early June to early September rarely get below 70 degrees even at night. This means that you will typically still need to rely mostly on your AC system during these months. You can still run the fan for a short time at night or in the early morning to improve your home’s air quality, but you don’t want it to run for long or your home will quickly become too hot.
You obviously also shouldn’t ever run a whole-house fan at the same time as your air conditioning is on. Not only would this increase your energy bills, but the fan would also constantly draw all of the cool air from your AC back outside.
Another thing to consider is that whole-house fans really should never be used on overly humid days no matter what the temperature is. If you were to use the fan during humid weather, all of the moisture it brings in could cause condensation to start forming on your walls and other surfaces and potentially lead to water damage and mold growth.
By drastically increasing the humidity level in the home, the fan would also force your air conditioning to work much harder once you turn it back on. The higher the humidity level is in the home, the more slowly your AC system will cool and the longer it will need to run. In turn, this would lead to greater wear and tear on the AC system and higher energy bills.
None of this is to say that whole-house fans can’t be useful as they definitely can as long as they are used correctly. When used in cooler weather, a whole-house fan can cool your home down much more quickly than your AC ever could while also using much less energy. In fact, most fans can lower the indoor temperature by as much as 30 degrees in only an hour or so.
Part of the reason for this is that the fan will quickly draw all of the hot air out of the attic. This is important as all of the heat that builds in the attic during the day is one of the main reasons why a home gets so hot in the late afternoon/early evening. This is especially the case if your attic floor isn’t well insulated since this will make it easier for the heat to flow out of the attic into the conditioned living areas.
Despite not using that much energy, whole-house fans are quite powerful. As long as the unit is the proper size for your home, it will be extremely effective at circulating air and drawing heat and pollution outside. In fact, the fans are so effective that they could quickly cause your home to get too cold at certain times of the year. In the early spring and late fall, you will usually want to shut the fan off as soon as it has cooled the home to the desired temperature. If you were to leave the fan on all night, you could easily wake up to find that the temperature in the home is 60 degrees or lower.
While whole-house fans do have some limitations, they can still be a great way to lessen the wear and tear on your AC and reduce your energy costs. The fact that they draw so much air out of the house also makes them a quick and effective option for boosting indoor air quality. If you’re interested in learning more about whole-house fans or you need any heating or cooling service in the Bastrop or Round Rock areas, contact Blue Ribbon Cooling & Heating today and we’ll be happy to help.