Thermostat Settings and Staging Discussion

Discussion in 'General Discussions' started by Chief_13, Jul 4, 2020.

  1. Chief_13

    Chief_13 New Member

    How do I figure out the optimal thermostat, temp, and staging settings for my house? I'd define "optimal" as the most efficient settings that give me adequate comfort.

    Sub-topic questions:

    It's generally said that the temp should be left constant in the house for the geo system to run most efficiently, but first off, is that even always true? If the system has no problem recovering from a setback, in a timely fashion, does that make a setback (for example, when we're at work and the house is empty) a good move? Even if the temp SHOULD always be left constant, that's not even straightforward when upstairs and downstairs are several degrees apart, and different areas are occupied through the day.

    I've got a two-stage system. If Stage 1 is slightly more efficient and produces better comfort, should I be trying to make the system run in stage 1 as much as possible? My system seems to run about 50/50 in stage 1/2 as it is set up by default.

    Should settings be fundamentally different between heating season and cooling season, or do all the same rules apply?

    I'm near Chicago, have an EcoBee 5 thermostat and a GeoComfort Navigator 5 ton water/air system. I know there are tons of variables here. I'm just looking to start the discussion, see where it goes, and learn something. Thanks in advance!
     
  2. mrpac

    mrpac Member

    Hi Chief,

    I have a 2 stage system as well, new to me 2 years ago. I came from a subdivision built gas-fed forced air home, and both my wife and I work throughout the day. We got accustomed to setbacks, about 5 degrees sometimes!

    In the geo system, we have tried setbacks, but only 1-2 degrees. I monitor the hydro with Hydro One online distribution tool, and it provides a graph of the instantaneous power consumption throughout the day.

    I tried to keep the system not running when peak hydro occurs, but is sometimes unavoidable.

    In the end, I have followed advice from other geo folk here.....and kept the temp at 20deg throughout the day, up or down according to heat or cold months.

    BTW, I had the EcoBee at my old place, but see no value in changing my Climatemaster Thermostat for a wifi enabled device. I am a tech, and am quite frankly sick of web enabled devices. I just want my HVAC system to run....the wifi part of that is unnecessary IMO.

    Let's talk,
     
  3. SShaw

    SShaw Member

    To figure out what's "optimal" will probably require some measurements, either of the unit's power consumption in different stages and with different settings, or of the daily power consumption.

    I use a setback on my GSHP when I am out of the house for four or five days. It's definitely cheaper than keeping it running when I'm not there. The conventional wisdom to avoid setbacks is partly because of the risk of engaging expensive AUX heat to recover. If you allow enough time to recover and can avoid AUX then that's not an issue.

    Pumping power and fan speed are two of the biggest factors for efficiency. Make sure your pump is an efficient one, is sized appropriately, and is set to move only as much water as necessary. Unless you have a variable speed pump, you might not be able to do much about this after installation.

    For lower power consumption, better comfort, and less noise, you may be able to adjust your fan speed from the defaults. I had to experiment with mine this Summer, as the initial settings used in Winter didn't work as well in the Summer. With the initial settings, the lowest stage was using compressor and fan speeds that were higher than necessary, making the system loud and creating a blast of cold air. Also, the high stage was using compressor and fan speeds that were not high enough, causing trouble meeting the set point in the upstairs. After adjustment, the system maintains temperature well and is almost silent. I'll need to see what happens this Winter. I may need to use different settings for Summer and Winter, which makes some sense because the relative loads for upstairs vs downstairs change.

    Mine is a variable speed system with two zones, so there are numerous settings to adjust. Your optimal setup will depend on what settings you have available to adjust. What settings do you have available?
     
  4. gsmith22

    gsmith22 Member

    I avoid setbacks like the plague and not just because I have heat pumps. I kept constant temperatures too when I had gas fired equipment and I think we are better for it. Air changes temperature more quickly than 'stuff' (house construction, FFE, etc.) because air has a lot less mass than the 'stuff'. By using setbacks, you are forcing the things with mass (drywall, wood framing/insulation, furniture, appliances, cabinets, etc.) to give up their heat to the air (that is now dropping in temperature entering the setback). Upon exiting the setback, you have to heat up the air to force heat back into the stuff (as the stuff now takes heat from the air). I fail to understand how daily cycling the temperature of the stuff (and air) saves money. I have a hunch, that the temperature cycling causes deterioration to stuff from constant expansion/contraction. Temp changes also tend to cause moisture changes which isn't helpful to most stuff as a lot of it is built from wood or wood based materials.

    Going on vacation for two weeks, sure I'll change the setting to less hot (in winter) or less cold (in summer). But daily setbacks? I doubt very much any energy is saved (you heat it or cool it back up again) and you are putting your stuff through countless heating/cooling cycles that causing expansion/contraction that almost assuredly leads to wear/tear. Since ending setbacks, I find I have a lot less open joints between trim, drywall, cabinetry, etc. And everyone is more comfortable. win-win as far as I am concerned.
     
  5. Deuce

    Deuce Member

    I keep mine the same except we do have a 2 degree setback in the summer in the evening for better sleeping in the Master bedroom.
     

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