To Setback or Not

FJL

This sample size might be too small, but I decided to stop using a setback for the past two billing periods, which was from approximately Nov 10 - Jan 11. I have a single pipe steam system fueled by gas.



I reside in a four-unit coop apt in New York City. Last year, we set out t-stat to be at 68 during the times that people were home, which was 3:15 p.m. to 11:00 p.m. and 5:30 a.m. to 8:45 a.m., and at 66 the other times. This year, we set our t-stat at 68 with no setback. The t-stat is triggered by a remote sensor in the top floor apt.



One thing to know is that there were times when we would adjust the t-stat setting higher because one or more residents wasn't getting enough heat. We have a heat balance problem in that sections of the building tend to get less heat and some days we need to boost the t-stat to heat those sections.



Here are the results. We used less fuel per degree day for the two periods as compared to last year. In the period from Nov-December we used .54 therms per degree day last year and .47 this year. In the period from December-January we used .61 therms per degree day in each year. This year was warmer than last year in that we had more degree days last year.



I also think that this year, during this period, we were turning up the t-stat more often as compared to last year to get more heat in the sections of the building that get less heat. There also was one day this year, during the blizzard, when the boiler went down, so we probably had a 12 hour period in which the boiler was off, so figure our usage would have been a bit higher this past period but for that. In any event, I'm somewhat surprised by the results.

Jamie Hall

Thank you!

A very helpful contribution to our ongoing debate here!

David Nadle

uncertainty

The US DOE claims you can save 1% fuel for each degree of setback if the setback is 8 hours a day. That's not very much! Your 2-degree setback for 12 hours might have saved 3% fuel. I'll bet that 3% is less than the uncertainty in the estimate of heating degree days and how closely it relates to your building.



I think the steam setback debate is a bit of a catch-22. It's hard to do the definitive large (10 degree) setback without overshoot or performance issues, and the small setback gives results that are indistinguishable from noise.

nicholas bonham-carter

imbalance?

have the imbalancing causes been found and corrected by now? improving the chances of simultaneous steam arrival on the top floor would give the maximum savings, so as to preclude the necessity of often having to change the thermostat settings to warm up a cold area.--nbc

Mark N

Savings

The website for my gas utility claims the savings are 3% for every degree of setback. So lets say I keep my thermostat at 70 for the whole winter and my gas bill comes out to $1000. So according to their math if I set the thermostat to 65 for the whole winter my bill should be $150 less or $850. I definitely agree my bill will be less if I use a constant setback, but what is kind of unclear is how much saving can be realized by using setbacks of a set amount of hours each day. I don't know about you but I myself prefer comfort and keeping the thermostat at 70 provides that. At 65 I think there would be discomfort and I would have to put that $150 I saved on gas towards a Heat Surge fireplace with the amish mantle to thaw out the wife.

FJL

Imbalance Solution

There are several problems that cause a certain section of each apt -- the master bedroom area -- to be colder.



First, the master bedroom is poorly insulated. Mine needs a new floor and I have five windows in the room that could do better to keep out the cold. This is a pretty significant reason for this room almost always being several degrees colder than the rest of my apt. Even still, there are times when the t-stat calls for heat and is satisfied before the rads in this section of the apt have time to get warm let alone warm up the room.



Second, the t-stat often is satisfied before the remote sections of the building have had a chance to warm up. I don't believe that this is a venting problem. The steam arrives reasonably simultaneously at each riser (within 4-5 minutes). The problem is that the risers for the living room are fed directly from the header rather than from the main and they get heat quicker. I've tried to compensate for this by slowing the venting on the radiators in the room with the sensor. Each now has a Gorton 4, but that still doesn't work.



What I think we'll do next is purchase a t-stat with a wireless remote sensor that can be placed in the coldest section of the building and regulate the heat in my living rooms, which I expect will get more heat, by using TRVs.

jpf321

remote sensing t-stat...

normally takes an average between the base and the remote sensor...I think I did find one where the remote was the only input rather than an average but I forget now what I had found..it wasn't a normal brand such as white rogers or honeywell

icesailor

Setbacks:

The idea is to setback when you are sleeping and when you aren't home. I don't think your apartment application is a very good application for set back.

My set back is 10 degrees. 10 hours at 68 degrees, 14 hours at 58 degrees. On weekends, I might set two zones at 68 during the day. I know beyond any doubt that my set back thermostats save me money. And I'm not uncomfortable or cold.

I would think that thermostatic radiator valves would be a better choice. Let people control their own heat. No matter where you put the thermostat, someone is going to be uncomfortable.

FJL

Honewell Prestige

I believe the Honeywell Prestige can be programmed to be governed by the remote sensor only. I'm pretty sure I got that information from a Honeywell tech on the phone or a retailer familiar with the working of that t-stat. I guess I should check the manual or install instructions to confirm that information.

Carl1979

Setback wins in my house for Money, AND Comfort

Typical night at 10:15 the thermostat setbacks to 58 from 68 degrees. Soon after its time to turn in for the night . put my flannel P. J.s on and climb between my flannel sheets. topped with a great down comforter .

I don't care how cold the room gets I'm as warm as can be, my only concern is, This going to take one toe, or two toes , sticking out of the covers to not overheat .

come 6:30 a,m, the thermostat comes to life by 7:30 every radiator in the house is fully engaged like mini blast furnaces. [ A true joy to behold ] the bedroom and bathroom filling with latent heat . for me its the best time to climb out of bed and start the day.

jpf321

zoned steam?

you mention zones .. are you running steam? 1-pipe or 2-pipe? how are you zoning the steam? thanks. 

jpf321

i think this is what I found previously...

Venstar Wireless T-Stat:

http://www.venstar.com/Thermostats/WirelessR/

Available: http://www.smarthome.com/30403A/Venstar-Wireless-Thermostat-System-No-Need-to-Rewire/p.aspx



This may also work: Control4 Wireless T-Stat:

http://control4.com/residential/products/climate/wireless-thermostat/

UserGuide: http://control4.com/files/products/data-sheets/Control4-WirelessThermostat-UserGuide.pdf



This is unclear without diving into the manuals (bottom of page linked below) .. Honeywell FocusPro Wireless:

http://customer.honeywell.com/Honeywell/ProductInfo.aspx/YTH6320R1001

PEXSUPPLY: .. http://is.gd/CBVgbO