how a smart outlet and box

fan lowered my electric bill

The month of July I was able to lower our electric bill $45 with a $10 smart outlet and a box fan. You may even have one or both of these items laying around. As a former HVAC technician, I know without a doubt that the furnace and air conditioning are the largest consumers of energy in your home more times than not. Especially when its extremely hot or cold outside. When the days are hot and the nights are cool, we have the ability to gather some of that cool night air and bring it into our home and cool our house down with a box fan. I figured out how to harness the cool air in order to not run our air conditioning as much in the peak of summer. And let me tell you, a box fan is WAAAAYYYY cheaper to run than a heat pump or air conditioner.

I will explain what I do and then you can adapt the same strategy to your home. My wife, Steph and I live in a two story house. Before I go to bed, even though it’s still warm outside, I open a window down stairs and I put our box fan in it. That box fan is “on” and plugged into a smart outlet but the outlet is “off”. The next step is to schedule the smart outlet and box fan to come on at midnight, 2 am, or whenever your best guess is for “it’s colder outside than it is inside”. Sometimes the weather app on your phone can help you figure this out. There’s a more ‘techy’ way to find this out but I will save that for another day.

So now, you are scheduled to blow a bunch of cool air inside your house. Well now you have to let some of the hot air outside your house to make room for the new air coming in. If you live in a single story house, open a window on the opposite side from the fan so the air can travel all the way through the space cooling it down. But if you live in a two story house like I do, open a window upstairs.

Pro tip: heat rises, so don’t fight science, blow cool air in downstairs and let the hot air up stairs get pushed out by the fan that is down stairs. Feel free to open extra windows if you find it to help (it doesn’t always).

Now close your bedroom door and go to sleep. If a little warm air drifts in your house it won’t get into your bedroom before it cools down enough outside that the fan kicks on and starts cooling things down. In other words, don’t be worried about the 1-2 hours that some warm air may drift in when the next 4-7 hours of cool air get forced in right after that. Besides, you’ll be asleep for most of that.

Remember when I said there was a more ‘techy’ way to do this other than checking out my weather app? I have an indoor temperature sensor and an outdoor one that I programmed. These temp sensors have helped me find the perfect window of cool air for our microclimate.

Here is a quick example with charts from my home. This morning at 6:16 am my kitchen was 67.45 degrees.

At the same time, the outside temp was 59.59 degrees.

So I decided to open up my windows and turn the fan on.

By 8:00 am the outdoor temperature was approaching the same as inside. Which meant it was time to turn the fan off and close all the windows.

This is the best part!!

If you look at these next two photos, you will see that at 6:17 am the kitchen read a temperature of 67.47 degrees.

At 12:34 PM, the kitchen read 67.48 degrees! 6 hours and 17 minutes later it was still the same temp. THIS IS ALL BECAUSE WE COOLED WITH THE FAN!

If we hadn’t, the indoor temp would have drifted up higher and higher starting at 6:17 am not 12:34 pm! THIS IS HOW YOU SAVE!

Now can you see how much more this can help if we use a smart outlet and start the fan even earlier in the night and have it run longer? Also remember, we are not just trying to cool the air inside the house, we are trying to cool down the mass of everything inside the house. By working to cool down the mass, this is how you are going to keep your house cooler for longer in the middle of summer.

This method isn’t just for summer, it can work for cooling your house 100% of the time in the spring and fall! So switching to this method for 8 months out of the year, you’re lowering your electric bill and your savings will help pay for your smart outlet and your box fan in no time.