Results 1 to 7 of 7
  1. #1
    Join Date
    May 2007
    Posts
    17

    Multi/variable speed thermostats?

    If I upgrade to a multi speed or variable speed furnace, does that mean I'll need a multi/variable speed thermostat? I have a Lux 7 day programmable now, but a single speed furnace.

  2. #2
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,744
    yes if you upgrade to a better system you will need a better thermostat to utilize the features you are paying for.

    getting rid of a lux thermostat would be a bonus.....

  3. #3
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    If you get a two stage heating and/or cooling equipement, then yes you should upgrade to a two stage t-stat.

    The furnace or air handler has a variable speed blower, then you can get a t-stat that has a built in dehumidstat (Honeywell IAQ) to slow down the blower to remove the humidity.

    Yes, there are some dealer that will say a single t-stat will work just fine on your new two stage furnace that you paid good money for, and you will not get the full comfort that you paid for in the first place.

  4. #4
    Join Date
    May 2007
    Posts
    17

    Got it

    A 'thermostat' controls the temperature. If I also want to control the humidity, then I need a thermostat with a 'dehumidstat' function to take advantage of a variable/multi speed blower.

    Thanks for the info.

  5. #5
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,295

    Thumbs up Kiss

    Quote Originally Posted by dcnj View Post
    A 'thermostat' controls the temperature.

    If I also want to control the humidity, then I need a thermostat with a 'dehumidstat' function to take advantage of a variable/multi speed blower.
    Relative Humidity will be low (< 53%) with a proper operating A/C
    during the cooling season with use of VS air handler and programmable thermostat.

    A dehumidistat is useful during the shoulder seasons
    (70's outside and > 63'F Dew Point) in some locales.
    If your locale has a very short shoulder season,
    you may not need a dehumidistat. Keep It Simple.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  6. #6
    Join Date
    May 2007
    Posts
    17

    Red face Multi seed OK to?

    I understand the benefit of a VS blower, but what about the 3-4 seed blowers. Like anything else, if I had the $$, I'd go with VS furnaces. When it's the cooling season, how do the multi speed blowers work with a single stage condensing unit, and standard programmable thermostat without a dehumidstat function?

  7. #7
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Multi speed does not change speed. It's set up ahead of time when the furnace is installed, say like heating speed is set at Med-Low, Cooling set at High. That's it. No ramp up or down.. Just sudden on and off.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event