Temperatures are heating up for the next week. With warm days and cool nights, the end of summer in Chicago is a unique opportunity to virtually eliminate your need for air conditioning – and it is easier than you may think! I think being green is all about doing the most with the least. “Fan Season” (late spring and late summer) is an ideal time to do more with less!
All you need is a couple of fans and a quick check of the weather. My list below will tell you when to use which fan to slash your AC use.
Fan Options:
- Ceiling fans - Consumer Reports found good options around $50-250.
- 1 window fan per bedroom – Window fans like this one recommended on Amazon run about $40 each. Window fans can pay back in a season!
- Fan unit on your AC equipment.
Paying a wee bit of attention to your local weather is key to getting the most out of your fans. Your local hourly forecast online, the Weather Channel on cable (“Weather on the 8′s”!) or your local weatherman like my favorite, Tom Skilling will give you all the info you need. Get a general idea of:
- Local humidity
- When night-time temperatures will start to drop and how low they will go
- If the winds are going to be breezy or calm.
Don’t forget to factor in neighborhood considerations. Open windows are not good for allergy sufferers or light sleepers! Be sure to consider allergy levels and sound issues before switching over to fans. Oh yes, and don’t forget to consider local wildlife too. Skunk mating season does not work well for using fans, and you could end up discovering a family of sparrows at 4 am that you didn’t know were your neighbors! If sound is an issue overnight, consider using fans with open windows at dusk and running on high for a few hours to cool the room completely. Then shut the windows before you go to bed.
The following strategies can help you cut or eliminate AC usage, while staying just as comfortable!
Skip the fans and AC altogether! – Just use your double-hung windows
- Ideal Weather Pattern: Breezy, and cooler (Outside temperatures are cooler than inside like when the temperature drops quickly after a storm or after sundown)
- Energy Savings: High – on the right day eliminates need to run fans or AC altogether!
- What to do: On the lower-level, open bottom window sashes part-way. On the upper-level, open top window sashes all the way. Warm air will rush out the upper level, forcing in cool air behind it from below.
Window fans (or a whole-house fan if you have it)
- Ideal Weather Pattern: Night-time temps are just above your typical AC setting, with moderate to low humidity
- Energy Savings: High –Eliminates AC altogether!
- What to do: Add 4 degrees to your usual AC setting. For example, if you usually keep your AC at 74 degrees and night-time temperatures will be below 78, your window fans (or a whole-house fan) will be a perfect substitute for the AC .
- Tips: Many newer window fans are light and super-quiet, and include a thermostat to shut on and off once the room reaches the desired temperature.
Ceiling Fans Only, No AC
- Ideal Weather Pattern: Warm but bearable (ie, temperature inside your home remains under 80 degrees), humidity 50% or lower
- Energy Savings: High –Eliminates AC altogether!
- What to do: A ceiling fan circulates air and cools you, making the actual temperature in a room seem up to 4 degrees cooler than it really is! So, if you like your home to feel like 74 degrees, you can run the ceiling fans and skip the AC up to 78 degrees and still be comfortable.
Ceiling Fans with AC; AC Fan On
- Ideal Weather Pattern: Hot and/or humid
- Energy Savings: High – Setting the AC thermostat 4 degrees higher saves 12-16% on electricity!
- What to do: As above. The ceiling fan will make you feel cooler so set your thermostat 4 degrees higher. Then, switch the fan on your AC thermostat from “auto” to “on”. The fan will pull cooler air from cool spots (like your basement) and mix it with warmer air (like in the second floor bedrooms), allowing the AC to run less.
