Reducing Thermostat When Not Home

If you have a programmable thermostat and you set it to allow an appropriate recovery time, there really isn't a comfort factor to consider. It's true that the net savings from setbacks probably isn't large in most cases, but it's still something. I've used setbacks with coal, oil and NG heat, and I don't see how the fuel makes any difference of you are saving $ by holding back on making heat when you don't need it.

Mike

Pacowy wrote: ↑

Sat. Feb. 02, 2019 8:31 am

If you have a programmable thermostat and you set it to allow an appropriate recovery time, there really isn't a comfort factor to consider. It's true that the net savings from setbacks probably isn't large in most cases, but it's still something. I've used setbacks with coal, oil and NG heat, and I don't see how the fuel makes any difference of you are saving $ by holding back on making heat when you don't need it.

Mike

+1

The general consensus (once promoted by our government) is that there are fuel savings which are typically on the order of 3.5% for each degree of setback. I must inject that this logic is flawed. Only the first degree of set-back works this way. The second degree of setback can only save an additional 96.5% of 3.5%, the third degree saves 0.965 * 0.965 * 3.5% additional, the fourth degree saves 0.965 * 0.965 * 0.965 * 3.5% additional, etc....

Otherwise a T=Stat setback of 29 degrees would get you to the point of greater than 100% energy savings, such that if you cut your T-Stat back from 75 degrees to 46 degrees, the utility company would be sending you a check each month.

There are definitely some fuel $$ savings to set backs and lower 'stat settings. How much $$ 'depends'.

But....
The look on oil or propane burners faces when you say your house temp is 71* and you are generally wearing a T shirt inside when its 5* outside.....

PRICELESS!!

Do the proponents of no setback leave their car running when not in use to save fuel?

The laws of physics are on the side of setbacks, period.

A few years ago I posted a set-back savings calculating spreadsheet that had the flaw I outlined above. Attached here is a corrected version (corrected correctly I hope ) that eliminates the outlined flaw.

scalabro wrote: ↑

Sat. Feb. 02, 2019 10:01 am

Do the proponents of no setback leave their car running when not in use to save fuel?

The laws of physics are on the side of setbacks, period.

lol. No I do shut my car off. However I don’t live in my car and it’s not a thermal mass that requires large amount of energy to recover. Look, I get it. But I burn coal so I do t have to nickel and dime my thermostat and fret over pounds of coal burned. I put 6 tons in my bin for about $1200.00 bucks and it heats my home and hot water mid October through April. I’m very happy with $200.00 bucks a month for that and it’s not worth it to me to try and monkey with it for pennies. Your mileage may vary. It’s not wrong or right. It’s what works for me. I’m pretty sure some folks on here are rocket scientists. Calculating formulas etc. that’s fine too if you enjoy it. I’d rather drink a beer and enjoy the warmth without all the math. I’m self employed. I’ve got dozens of other things to worry about that matter a lot more to me. Maybe when I retired I’ll be weighing pieces of rice coal. In the mean time when I walk in the door I want it uniformly warm and I don’t want my boiler to be out of breathe from doing so. By the way I do have a programmable thermostat with WiFi. I do set backs in summer. Go figure.

scalabro wrote: ↑

Sat. Feb. 02, 2019 10:01 am

Do the proponents of no setback leave their car running when not in use to save fuel?

The laws of physics are on the side of setbacks, period.

I respectfully disagree... I think.

I think of it as this... a car you can shut off and easily start again but a coal burning appliance we cannot. Well, we can but not without a bunch of fanfare.

I don’t have anything real intelligent to say here but I sort of agree more with CoalKirk on this one. Those of us with hot water units... aren’t we in effect just storing up BTUs that we will eventually use anyhow?

I know we have had this discussion man times before. I guess to each their own.

Hahahahaha I agree with you guys too!

I burn coal simply because I love the type of heat and freaky looking antiques

I’m just saying that beyond comfort, if you don’t burn fuel you save money.

Mike Pacowy explain it best IMO earlier in the thread.

2biz wrote: ↑

Sat. Feb. 02, 2019 7:53 am

That statement pretty much says it all!

I tend to agree with this as well. But If you do decide to setback, just do the warmup an hour or so before you plan to get back and will hardly notice it. If it takes more than an hour to warm backup,leave it be. Personally i use so little coal in an avg season,and even in a colder than avg. season. I dont bother to do setbacks. Its 78 in this old barn right now.

For Sh$ts and Giggles, I used the calculator and I'd save a whopping $.27 cents a day if I programmed a 2° setback. Even that is debatable since my AK-110 heats the house down to about 45° with a zero feed rate! Most days through the winter the setback wouldn't do a thing. Think about it! Even if you burn 20lbs a day at idle, how many BTU's are you pumping into the house?! Something the calc doesn't compute.

Thanks Larry for the spreadsheet. According to the calculator, I would save anywhere from $50-$100 over the course of the entire heating season depending if I went with a 2 or a 4 degree setback. That being said, I believe the calculator assumes you are turning your thermostat down X degrees over the entire season compared to a previous season. If that is the case, in reality, doing a setback each day of the workweek for approx. 8 hours a day probably brings me down well below the $50 in savings over the season. To complicate my situation, I'm not just heating with coal. My 1970's split-level house has two separate heat pumps with two separate duct systems. The previous owners ripped out all of the baseboard electric heat and went heat pump/central air about 20 years ago. They also installed a propane insert in the family room. They installed the coal stove much later, probably because of the electric cost. When I switch to coal for the season, I'm shutting down the first floor heat pump and using the stoker through that ductwork. Right there I'm saving money. When we are not home, I turn off the propane insert. That saves a little more money. The heat pump on the second level is what kills the electric bill when you get below 20 degrees outside. Eventually, I'd like to get some ductwork from the stoker in the basement up to the second level, but the layout of the house is not ideal for that. That's a project for another day! For now, I think I'll keep the setback on the coal to 2 degrees and the heat pump to 4. Let some of the heat from the first level rise and keep the heat pump from kicking on as frequently. Like someone else said, to each their own

Eab91276 wrote: ↑

Sun. Feb. 03, 2019 4:22 pm

Thanks Larry for the spreadsheet. According to the calculator, I would save anywhere from $50-$100 over the course of the entire heating season depending if I went with a 2 or a 4 degree setback. That being said, I believe the calculator assumes you are turning your thermostat down X degrees over the entire season compared to a previous season.

Yes, it is based upon current change (temperature set-back) of past historical coal usage for a past historical T-Stat temperature and it is indeed intended for entire seasonal adjustment. If you only fractionally adjust, you must fractionally compensate accordingly. For a highly simplistic example, if you set back your T-Stat by 3 degrees for 8 hours each day, you are effectively only cutting back by 1 degree per day. For this case, 1 degree of T-Stat set-back would be entered into the spreadsheet, and not 3 degrees.