So, Cecil is telling me that my $1,000,000 idea will also save people money? BRILLIANT!
My idea was to have the ability to program a temperature range for your house. For example, in the winter, you set it to be 65-74. When the house drops to 65, the thermostat kicks in, heating the house to 74; it then turns off, until it drops to 65 again.
The electronic thermostat on my gas fireplace operates in a similar fashion to what you describe: you set it for X degrees, the heat kicks in at X-1 and stops at X+1. (If I set it for Celsius it counts in Celsius, so it starts less often but heats longer than for Fahrenheit.)
You’re just talking about a range of X-N to X+N, which would further decrease comfort… but it would still do its cycle pretty much at random throughout the day. Cecil says programmable thermostats are more efficient because they follow the outside temperature, and only become efficient if the “less heat” part lasts about 8 hours.
[ol]
[li]Why is someone in BC using Fahrenheit measurements on his thermostat?[/li][li]Who the heck can sleep with the temperature below 68? I’d be shivering and my wife would be a Popsicle.[/li][/ol]
Powers &8^]
I can answer the last question, there is nothing better (for me) than sleeping in a cold room, I would think that 68 (20C, right?) is still too warm. You jump into bed and between your body heat and your covers you get this warm ‘nest’ that is all the better because the rest of the rrom is cold. I don’t know if this makes sense, but it is just like how I sleep better when it is raining outside, I just do.
1.) In Canada, the Fahrenfeit scale is still commonly used for such things as inside air temperatures, the temperature of water in lakes, rivers, and swimming pools, and oven temperatures.
2.) I would assume almost everyone with a pulse would be able to sleep with the temperature below 68 F (20 C). That’s not cold at all! Even 60 F (or 15.6 C) is still a fairly comfortable temperature for sleeping.
Also, your wife would not be a popsicle since water doesn’t freeze until you get down to 32F.
Actually, most high efficiency fuel burning furnaces are equiped with a low and high fire cycle which are controlled by the thermostat. The low fire is used to maintain constant temperature but the high fire will kick in when the demand for heat is greater such as in the morning after a setback period.
You logic isn’t flawed at all. In fact, T-stats already do this. Most digital ones have a setting called Swing (or Swing Value or Swing Setting). It does exactly what you say. If we adjust your example just a bit, say 65-75, that would be a T-Stat setting of 70 with a Swing value of 5. If you Google Thermostat Swing I’m sure there’s plenty to read about it and if you look Honeywell or another manufacturer I’m sure you can find some instructions online that explain how to set it.
The smaller the swing value the more comfortable it is for the people inside, the higher you set it the easier it is on your equipment. I believe most t-stats are set with a swing value of 1 or 2 from the factory.
I agree with Cecil if the furnace is strictly a heat generating unit. If it’s a heat pump that moves heat from the outside to the inside it gets more complicated. Here’s a linkto a post I made in a thread about coefficient of performance (COP) in heat pumps.
After discussing the “valve theory” of thermostats with 3 of my male co-workers, we conclude that the 50% of the population that subscribe to the valve theory constitute 100% of the women.
FWIW Cecil is aware of more advanced/modern furnaces which have multiple heat levels, and heat pumps with two or even three-stage compressors. Cecil and Ed have to fit things into a rather harsh word limit in the paper, unfortunately, and write to a much more broad audience too.
Shivering Ally McBeal anorectics need more heat. Comfortable sized middle aged women at the mercy of excrutiating hot flashes need less heat. I turn my thermostat down as soon as the family is out the door (I’m one of those lay-about housewives) and the house is a chilly 62 degrees all day. I’m not cold, and if I am, I put on a cardigan sweater. Turn the heat back up at end of the day so family can walk around wearing t-shirts as if it’s an afternoon in July. I’m probably saving energy $$$ unbeknownst to the family, an unsung heroine.
Thermostat setback and setup makes sense when you’re heating with gas/electric, but what if you’re using a heat pump? Heat pumps operate more efficiently when the temperature difference between the outside and inside of your house is small. The early morning right before sunrise is the coldest time of the day. By setting back your thermostat at night, you’re forcing your heat pump to heat up your house during the time it’s least efficient.
The same goes for air conditioning. It’s most efficient during the coolest part of the day. During the summer, does it make sense to turn down your thermostat in the early morning (i.e. chill it) so that the air conditioning doesn’t come on as much later on in the day when it’s less efficient? Or are the savings completely lost as your extra-cool house absorbs heat faster from it’s surroundings?
My wife is a brilliant person. Yet when the air conditioning is on in her car and she gets cold, she turns up the heat. She argues that this ‘turns down’ the air conditioning. I try to argue that she’s wasting energy, and that it’s like running the heater and air conditioner at the same time in our house, but she doesn’t believe me. :smack:
Actually, on most cars the temperature control just blends heat with the air conditioned cool air so she’s sort of right in that the effect is the same.
Yes…the effect is the same. However, if she’s cold, she should just turn off the air conditioner. But she thinks the temperature dial controls the ‘power’ of the air conditioner (i.e. the air conditioner unit puts out less cool air).
Lots of people already beat me to it, but I came to say the same. My house has a ground source heat pump (so-called geothermal). If I use the setback in extreme conditions, the auxilliary, resistance-only heater kicks in. It’s not a multi-stage compressor, but it’s wired as a second stage. Resistance heating is expensive. On the other hand, my electricity rate is only 50% because I’m “green,” and that goes for the air conditioning during the summer, too, so I don’t sweat it.
Anyone who lives in Rochester is encouraged to become familiar with the concept of blankets, which have been shown to be surprisingly effective in addressing the problem of sleeping comfortably in cool and even cold rooms.
I think that you will find that there is one exception to setback thermostat savings. That is steam heat. My evidence is mostly anecdotal, but others have expressed the same findings. I tried a setback thermostat for a few years and compared my consumption per degree day and found no reduction. In fact, some months there was a slight increase.
A steam boiler holds a large amount of water and heats it to the boiling point when heat is required. But it only has to turn a small amount of that water to steam in order to fill the radiators.
A hypothetical boiler holds a hundred pounds of water and needs to fill hundred cubic feet of pipes and radiators. It takes one BTU per pound per degree F to raise the temperature of the water in the boiler and approximately 1000 BTUs to turn one pound of that 212F degree water into steam. It takes about 4 lbs of steam to fill those pipes.
So, it takes 14200 BTUs to bring the boiler water from 70 to 212 and another 4000 BTUs to produce the steam needed. Because the BTUs needed to heat the water up are not productive, it is most efficient to keep the water in the boiler as close to the boiling point as possible. Extended periods of inactivity, let the temperature of the boiler water drop. This heats up your basement, but making up the difference is inefficient.