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Programmable Tstat for hydronic system

R. Kalia_8
R. Kalia_8 Member Posts: 54
I hope you don't think a stat will save you any significant money. The savings will not be noticeable.

Insulation will definitely save you money. There may be other aspects of your system that can be improved, but we can't see them from here. Using a indirect for hot water won't save you much money, because hot water is not such a big expense to begin with. Changing it from electric to gas is definitely worthwhile, though.

PS The big pipes MAY indicate a system that was originally gravity hot water, i.e. ran without any pump and so needed large pipes.


  • Ararock82
    Ararock82 Member Posts: 2
    Programmable tStat for hydronic system / Energy Conservation

    We moved into a 90 year old house in October. I just went thru about 500 gallons of oil in 3 mild months (we live near Philadelphia) It is a three story home --all stone, very little insulation. The oil fired boiler is a 10 year old Peerless; it has been inspected, and is in good condition. There are two circulator pumps on tstats:
    Zone 1 - 1st and 2nd floors with hot water radiators
    Zone 2 - 3rd floor with baseboard radiators

    Can I replace the round Honeywell Tstats with programmable ones? What programmable Tstat can someone recommend? I have been looking in Graingers catalog--all seem to be for air systems (Fan switch on every one).

    Any ideas on energy conservation --should I look at insulating the pipes in the basement? (IT looks like it may have been a steam system at one time --main pipes are close to 3")

    The house itself is not well insulated -- 16" thick stone with furring strips and plaster board. we insulated where we could during renovations before we moved in, but that was only in 4 rooms. It's a great house, but it looks like it will be more expensive to heat than we predicted.

    Any other ideas would be appreciated--I moved from a house with a gas fired forced air system---this wethead stuff is new to me.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Nearly any programmable thermostat

    will work so long as it is geared to the correct voltage (i.e.: 24 volts versus millivolts). Your typical off the shelf thermostats often say "compatable with 99% of existing systems" or to that effect.

    The newer technology (Honeywell's "Smart Response" and other similar ones possibly under license) are my favorites.

    What is key is that they self-educate to start the system early enough to meet temperature WHEN you tell it to be there.

    (This is as opposed to you guessing how far ahead to start the system to have it warm when your feet hit the floor in the AM or you get home in the PM.)

    Example: You set the temperature to be 68 degrees at 5 AM.
    Day one the system starts an hour or so ahead. If it gets there ahead of or behind schedule (knowing it started from "x" temperature), it will remember the rate of rise and start earlier or later the next cycle. How cool is that??

    The one I have was about $100 and is a 7-day type (each day can have two set-back/recovery periods, individually).

    You will see others such as 5-1-1 (M-F the same, Saturday another and Sunday yet another schedule) or 5-2 (M-F the same, Saturday and Sunday the same. The fewer schedules possible the less the cost. The low end ones go for about $35 to $50 and the upper ones, like I said, about $100.

    BUT, the Smart-Response recovery feature may not be available in the lesser scheduled models, at least not yet. Worth asking.

    BTW, there was a Tradeline version of the one I have (Honeywell) and you really had to dig to find that it had the Smart Response feature.

    What you are asking is a "101" version of control that may work well for you. But there are lots of other strategies to save money AND increase comfort here. Stick around.

    Look sharp.

    Stay warm.

  • Peerlee have a DOMESTIC COIL?

    Dear Arorock,

    The new Honeywell T8000 series is wonderful for a set back thermostat. get the one for single stage heat and cool. It's touch scree and back lit. It even anticipates your heat demand so if you set 66F for 6PM it may turn your heat up at 5:30 so it is at 66 at 6! The stat is so easy to install it took me almost 5 minutes. You can even program it while sitting in your easy chair!! Did you know that the optimal set back for a heating system is only 7F? The Germans studies this for YEARS before they came up with the ideal setback!!

    An outdoor reset by Tekmar or HeatTimer will save you 14% on your fuel bills to! My favorite is the Tekmar 256 (use the 260 if you add the Indirect Water Heater).

    To save more energy and get more hot water, if your boiler has a DHW coil replace it with a Indirect Water Heater. Many are available but my favorites are the TR series by Triangle Tube or the MS series by Crown.

    Hope this helps,

  • Ararock82
    Ararock82 Member Posts: 2

    Thanks Brad and Steve,

    My system is a heating system only, and there is no provision for a domestic hot water heating coil. I presently have an electric HW heater, and I am thinking of replacing it with a gas HW heater.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    J. Cricket has a point

    in that a programmable thermostat is primarily a "convenience" device. And takes over when you leave for a week having set the house at 70 manually....ouch.

    And yes, insulate and tighten the envelope wherever you can...

    Another thought on that tack is house mass. That will play a role in your setback strategy. A too-long setback will take a much longer time to recover than a shallower setback will. One of many variables...
  • BillW@honeywell
    BillW@honeywell Member Posts: 1,099
    Yes, think of your house as a system...

    The heating system is designed to replace the heat your house loses. Windows, insulation, tyvek wrap etc all can help minimize that loss. Don't forget solar load and windlosses. Programmable thermostats like the Honeywell TH8110, TH6110 and TH4110 also help, and usually pay for themselves in the first year of ownership, especially if there is no one home during the day. 7 degrees seems a reasonable setback based on your home's heat loss. The stats mentioned above are available from your professional heating contractor.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    In general, uninsulated solid stone or brick structures have the least to gain with daily setback. The walls themselves can become noticeably cooler with deep setback and this will frequently result in keeping the thermostat at a higher "normal" setting for the same comfort level.

    If the house is typically unoccupied during the daytime you'll likely get the greatest setback savings by setting back 5° or so during the day.

    You might want to do (or have done) a good heat loss calculation for your house and compare to the boiler size. If significantly oversized (typical--particularly with gravity conversion systems) you may achieve moderate savings by using a lower flow nozzle in your oil-fired boiler.
  • Plumb Bob
    Plumb Bob Member Posts: 97

    > Programmable thermostats like the Honeywell

    > TH8110, TH6110 and TH4110 also help, and usually

    > pay for themselves in the first year

    Thermostats cost tens of dollars, nothing compared to a year's heating bill (thousands of dollars). So there is no way for a homeowner to verify this claim...too many other variables.
  • soot_seeker_5
    soot_seeker_5 Member Posts: 6
    hey BillW@HoneyWell - new DST law & T-Stats...

    hey Bill,

    last august, congress passed an energy bill that included extending daylight savings time by about a month. beginning next year, dst will start the second sunday of march and end on the first sunday of november.

    what is honeywell's policy on all their t-stats being sold currently that feature 'dst changeover' but where the firmware still uses the old fixed dates?


  • payback

    So far I have owned three houses. All three had standard thermostats in them. When I replaced them with programable set back thermostats I saw a significant reduction in fuel use, up to about 10% in my one house.

    I would agree that I would not set back a high mass radiant floor heat system. In my one house where I had a concrete floor, using set back in that zone actually cost me more.

    Geeze Cricket, bad experience with set back stats?

This discussion has been closed.