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The weather has been nice, but we all know what’s coming soon: substantial air conditioning bills! Air conditioners consume a lot of energy. It really shouldn’t be surprising just how much electric bills rise during the hot summer months. However, it is shocking when you get that bill! What if you could stay cool without paying so much? It is possible here in California and other parts of the country where hot days are followed by cool nights. The key is learning how to leverage our climate.

A central air conditioning unit uses 3500 watts of power. If it is running for 6 hours during the day at a cost of $0.47 per kWh (SDG&E’s current tier 3 cost), it would cost you $300 per month, just for air conditioning. In contrast, a whole house fan pulls 400 watts of power, which can run for 6 hours at 10% the cost of air conditioning, at about $30 per month! But what is a whole house fan and how can you use a fan to actually cool your house?

For this to work, you need to keep your house insulated during the day. Studies from the Department of Energy show that soft-colored draperies with white plastic backings can reduce heat gain by 33% and, when completely closed, highly reflective blinds can reduce heat gain by around 45%. We installed custom real wood blinds in all of our windows, except for those on the north side (without any direct sun on the north side, it really is optional on that side). The up front cost for this was not cheap (about $2000), but an investment well worth the energy cost savings they have given us over the past 9 years and they are beautiful.

At the heart of this operation is the whole house fan, which is not too difficult to install if you have an open day, a reciprocating saw (to cut into your ceiling), some 2x4s, a table saw (to make the wood frame needed to set the fan in the ceiling) and some good tunes. However, if you hired someone to install your blinds, then you should definitely get a handyman to do the job. You’ll also need to make sure that there is a power outlet in the attic to plug in a wireless/remote controlled electrical outlet switch, such as the TanTan Smart Plug which works with Amazon Alexa. The whole house fan is “always on,” so the wireless switch will allow you to turn on or cut power to the fan from anywhere in the house.

OK, you are now ready to learn the routine necessary to keep your house cool. You’ll need to get a good thermometer that shows the temperature both inside and out. Then, starting in the evening when the temperature outside has dipped below the temperature inside, open windows on all sides of the house except the west side (where the sun may still be beating down) and turn on your whole house fan. Wow! Friends who have experienced this at my house will attest that the breeze that rushes through feels better than AC. Cool air from the outside pushes any heat in your house through the fan in your ceiling, where it briefly joins the blistering temperatures in your attic, then the hot air pushes out through your roof vents. A whole house fan actually does a better job than your AC in cooling your whole house. Running the fan for a few hours cools the house as well as the attic, whereas AC is constantly fighting heat trapped in your attic.

Quite often we run our fan for 6 hours, turning it off when we go to bed…or sometimes running it all night to lull us to sleep. Why not? It doesn’t cost much compared to AC. Doing this will bring the house temperature down to that of the overnight low temperature outside, which can be a cool low 60F here. The moment the temperature starts to rise outside, it is time to shut off the fan, close all the windows, and all the blinds. No exceptions! It will become the first thing you do when you wake up. Don’t be lazy about this or you will pay for it – literally if you have to turn on the AC.

There are other new habits you’ll need to employ as well. First, do not use the stove or oven (or anything else that creates heat) until dinner time. Summer is a time to enjoy the outdoors. Make your pancakes on an electric griddle and/or have a BBQ lunch in the backyard. Second, you need to become a door autocrat. Do not let anyone keep a door to the outside open for more than a few seconds! You worked hard making the house cool. Let’s keep it that way!

With an investment of wood blinds and a whole house fan (the cost of which is made back with energy cost savings within 2 years), some planning, and new routines, we were able to stop using our AC, except for a few extremely hot evenings each summer. You can’t wait to do this to your house, can you? Your house will be cool and you will be saving a lot of money. Yes, it will take some work. But, with encouragement and determination you will get it done.

Speaking of that, is there someone in your life who inspired you to achieve? Cheered you on? Enabled your success? Keep your answer in mind and next week – I’m fairly certain I’ll predict who it is.