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Wow - that's a crazy amount of energy. As a Brit who's never been the south of the US, is that figure really true? 100kWh is about 300 miles in a Tesla, or boiling a kettle constantly for about 30 hours.

If that's really accurate, then I'm staggered at how much energy folks must be using to keep cool, and makes my efforts at saving energy seem paltry in comparison.



Yes, that is a crazy amount. I live in the South, and the highest we hit is about 35kWh on extremely hot weekend days. Our typical summertime use is more like 20kWh/day -- but according to our utility, we're using about 1/2 of what a typical neighbor uses.

Based on this very scientific single-neighborhood sample, I'd guess 40-60kWh/day would not be unusual during the peak summer months.


In the US, there are very large variations in house interior volume, insulation, and usage patterns. Upper-middle class house built on a slab with standard in Dallas with a stay-at-home mom, for example? I wouldn't bat an eyelash at 100kWh/day on the hottest and wettest days. Condo apartment in downtown Houston? That would be excessive.

US insulation requirements in Dallas is R-20 in the walls [1]. The PassivHaus standard is R-40 to R-60. I believe Germany requires R-5 at a minimum. Mainstream US construction design and practice still doesn't account for thermal bridging, so that defeats much of the insulation we're throwing into our buildings.

[1] https://eepartnership.org/wp-content/uploads/2016/02/Texas-2...


Texas also produces the most wind power of any U.S. state.

https://en.wikipedia.org/wiki/Wind_power_in_Texas

The source in wikipedia is out of date, but it's still true as of Q3 2016:

http://www.awea.org/Resources/Content.aspx?ItemNumber=9488


The Texas summer is brutal [1].

Last month my average home used between 100 and 120 kwh per day [2].

Luckily we rarely have to heat in the winter - although it's not uncommon to have the A/C running for Christmas.

[1]: http://www.statesman.com/news/local/wipe-that-brow-austin-re...

[2]: http://imgur.com/a/45oGu


>Last month my average home used between 100 and 120 kwh per day [2].

That's half of my entire energy usage for a month...

Have you considered a swamp cooler?


Swamp coolers work in areas that are hot and dry, like New Mexico or Arizona.

They do not work well if it's hot and humid, for two reasons. One is that the water doesn't evaporate as well, so they don't cool well. The other is that the whole point is comfort, and in a humid climate you don't achieve that unless you remove both heat AND humidity, but swamp coolers add humidity.

Texas has some desert areas (western part of the state), but most of the population lives in the part of the state that isn't a desert.

The good news is with modern construction techniques and equipment, you can cut energy usage WAY down. You can cut energy usage a lot with stuff like a radiant barrier in the attic, attic vents, lots of insulation, double pane windows, a "tight" house with little air leakage, proper angles to keep direct sun from heating up the house at the wrong times, and a high-efficiency AC unit that you service and maintain properly. In fact, a lot of those things are actually more beneficial than getting solar panels.


I've heard they are not effective with our extremely high humidity levels.


I live in New Jersey and just had solar panels installed on my roof. Peak power is about 7.8 KW. On clear days, power production in the summer is about 50 kWh

I have been keeping daily logs this summer and find that my daily power consumption swings between about 25 kWh on cool days to 65 kWh on really warm days. Definitely a lot lower than 100 kWh mentioned previously.


Needless to say, NJ is very different the South, and in any case this is highly dependent on the size of the house and the amount of insulation.


Remember, the south of the US is in the subtropics, roughly level with the north of Africa. Imagine living in Egypt and not running the AC constantly.


I spent much of last year in Southeast Asia within ten degrees of the equator and rarely had A/C. It wasn't a problem for me, though my computer was often unhappy.

I went to Egypt as a teenager and remember the temperature in Sharm el Sheikh cracking 50C. We would literally sprint from the A/C in the hotel across the beach to the water because the sand was too hot to walk.

Equivalent latitude doesn't mean equivalent climate. As an example, which of these cities is further north, Buffalo, NY, USA or Cannes, France? Hint: it's the one known for topless sunbathing, not the one known for sub-zero outdoor football games.


According to WolframAlpha, the hottest temp on record in Cairo is 118°F, while Phoenix, AZ has hit 123°F. Even the average high is 5°F higher in Phoenix.


There are a lot of people living in Egypt who don't have to imagine that.


Yes, but I was talking to a British fellow.


But obviously you shouldn't make such big/poorly insulated houses then.


I can't find where the site now, but there was a fairly compelling argument that it was overall still more energy efficient for people to live in Arizona and AC dropping the temp from 90F to 70F than to live in a northern state where for 6 months out of the year you have to heat the house from 20-40F up to 70F.


That seems likely. In imprecise terms:

A/C efficiency ("power factor") is measured using the ratio of heat (energy) moved outside to the amount of energy put into the air conditioner , which is usually >> 1 unless there is a huge temperature difference between inside and outside.

An ideal furnace has a 1:1 ratio of heat energy injected into the house to energy used to run the furnace. Heat pumps can get over 1:1 ratios, but come with caveats and are more expensive than A/C units.

Also, you can make it feel cooler with a dehumidifier, which often is more efficient than cooling. For furnaces, you need a sweater, but your article assumed a 70F indoor target.


Did you mean s/likely/unlikely/?


Even if you compare poorly built/insulated houses, cooling is much less efficient (per degrees vs outside temp) than heating.

Heating can also be made more efficient easily with insulation, and heat generation through CHP or geo heatpump.


Let's not get ahead of ourselves, 100kWh is not the "low limit" of how much energy you need to get an temperature controlled home in the South for a day.

This is the figure in an environment where electricity costs nothing and there is zero pressure from home design to the actual AC unit to reduce consumption. Let's face it, this attitude isn't going to fly in the future. You could probably cut that figure by a good 10% by installing your choice of solar panels or a bunch of trees, just from less sun hitting the structure.

(Cut it in half if you consider the average American in the South lives in a freakishly large house fit for a queen with entourage and is cooling all of it..)


It's 24/7 air conditioning working. In EU you get around 100kWh per day also if you use home air condition 24/7.




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