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Well . . . Most people probably save a little by adjusting their thermostat down (or up) when they don't need it, but the article you quoted is chock full of ignorance about thermodynamics and misinformation based on faulty assumptions.

In theory, thermostat setback and setup will almost always save energy, based on the following simple principle of heat transfer: the rate of heat loss (or gain) is primarily a function of the difference in temperature between two objects, such as your house and the surrounding air. In the winter, the colder your house is allowed to get, the slower it loses heat. Although your heater may run for a while during the recovery period when it's bringing the house back up to temperature, you still use less energy than you would keeping the house at a constant temperature around the clock.

False. Yes, the heat transfer depends on temp difference, but you can't tell me that this difference is diminishing while your house is cooling unless you are assuming the outside temp is constant. I don't know about weather in your part of the country, but where I live the temp outside changes. And often in Winter the temp outside drops far more rapidly than the temp inside - meaning the difference is increasing. Also, that same temp difference that can work in your favor as the temp outside falls works against you once you start heating the house up again. The argument above mentions that the heater may run for awhile but then ignores that very important fact.

Reality is far more complex than this simple minded and misinformed explanation. The details that matter include: the amount of insulation in your house, the comparison of the temperature gradient outside and in, and the efficiency of your heating source. The same programmed temperature settings that may provide you a net benefit on one day, could provide a loss on the next day.

One researcher estimated in 1986 that as much as half the populace subscribes to what he called "valve theory," namely the belief that the thermostat functions like a gas pedal: the higher you set it, the hotter your furnace runs.

This is an example of a completely irrelevant strawman. An un-sourced "researcher" once accused a lot of people of being ignorant about something that would not necessarily have had anything to do with this problem at all.

At one time the U.S. Department of Energy was urging Americans to install programmable thermostats, which can be set to automatically turn the heat down when it's not needed. These devices were thought to generate savings of 10 to 30 percent, and close to half of U.S. homes now have them. In 2006, though, the DOE stopped pushing the thermostats, which aren't cheap, after multiple studies showed the actual savings was zero

That seems like a d@mn important empirical finding that backs up actual detailed thermal dynamic simulations. The advantage of thermostat set back is marginal and can be negated depending on the amount of actual setback, temperature difference, outside temperature gradient, insulation, etc. But of course the author can't believe the facts are due to physics, so he rationalizes . . .

— not because the inventors hadn't understood the laws of physics, but because consumers didn't use the things right.

hmmmmm . . . Care to quantify that sweeping statement with any facts? We are supposed to believe that although half the homes in the US have programmable thermostats, that there is not a significant fraction of home owners who are smart enough to program them? Really . . . if a Republican teabagger made a claim like that, we would be all over them to justify such a claim. If only 20% of those users used temperature set-back correctly while the remainder continued to use constant settings, we should still see the impact of 10% of the population doing the right thing. There shouldn't be an advantage of zero. Are we to believe that for every consumer who used the thermostats properly, there was an offsetting consumer who actually did some kind of set-up program?

Una conducted a long-term research project in which she installed a programmable thermostat in her house, aggressively dialed back the nighttime setting for winter, then tracked her energy use for three years, using data from the National Oceanic and Atmospheric Administration to correct for outdoor temperature differences before and after installation. Result: she saved about 28 percent on her winter gas bill, enough to recover the thermostat’s $120 cost in three months.

I would like to see the results of that correction she made. . . primarily because I don't believe you can make a legitimate correction from such data. Remember, the temperature difference during heat cycles is what costs you energy. The average temperature outside does not directly translate into energy cost. But if she did save 28% doing this, then she needs to stop doing this study and seal her house better. Maybe she's leaving the screen door open. I'm also skeptical of how she established her baseline since the article doesn't mention that. I would have to know a lot more about Una and her study to think this really means anything. Frankly, not even the sellers of programmable thermostats are making these kinds of claims.

A study of two identical Canadian test houses showed an 11-degree setback overnight and during work hours generated a 13 percent savings in gas and a 2 percent savings in electricity (the furnace blower ran less). My guess is that's better than most people will get. A U.S. study of 2,658 gas-heated homes using programmable thermostats found a 6 percent reduction in energy use.

There clearly can be advantages. Depending on the climate where you live, and the insulation in your house, and how far & when you setback, you can realize energy saving. But, you can also lose.

This Canadian study is mentioned all over the internet . . . and like this article is misrepresented completely. Here's a description of the actual study (http://www.homeenergy.org/show/article/nav/coolingandair/id/...) The 11-degree overnight setback resulted in a 6.5% decrease in energy usasge. To realize the 13% this author mentions, the study had to cut back from 72 degrees to 61 degrees day and night. So, yes, if you keep your house cooler all Winter long, you will save energy. Also, this study was done for a total of 5 days.

It is also worth noting that what is actually meant by "identical houses" is important. The two identical houses used in this study are two story houses built side by side. Unfortunately that means that they do not get identical sun or wind exposure - two factors that can have at least as much impact on energy as the thermostat setting.

That's one of the reasons quantifying actual energy savings like this is so difficult. Note that the US study can be downloaded at (http://www.env.state.ma.us/dpu/docs/gas/08-123/31109bsgrd2a1...). I confess that I only skimmed most of this 27 page report. It is conducted by GasNetworks (http://www.gasnetworks.com/about/index.asp) a collaborative organization of gas companies. They sell training to contractors on how to install energy saving technologies and ran this study in order to convince the EPA not to sunset the ENERGY STAR programmable thermostats program. Their analysis involves mail surveys, evoking a second order PRISM algorithm to normalize temperatures, weighted least squares error fit to actual data, and significantly more mathematical analysis. All of this simply indicates that there are a lot of details required to get to their results. Generally, you are not doing that much curve fitting and statistical analysis unless there is significant variation in the raw data. I didn't find the raw data presented anywhere, but that is what I would suspect. Like I've been saying, you can gain, but you can lose.

I would point out that I do have a programmable thermostat and I do setback both Summer and Winter. But my annual energy usage over the past 3 years varies by more than these studies indicate I might gain over a constant setting.
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