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  1. #1
    Join Date
    May 2010
    Location
    Northern Utah
    Posts
    18

    Question Lennox G71MPP36B-070 & XC15-024

    My purchase also includes Lennox Power Humidifier WP2-18
    Lennox Healthy Climate Air Cleaner Merv 10 Media

    I am replacing a 31 year old original furnace and adding central a/c. I currently have an evaporative cooler as my main cooling source. I live in a split entry home in northern Utah and the evap cooler works fine for my cooling needs. I'm just tired of trying to find people to climb up on my roof to service it and it's over 12 years old and I'm not sure how much longer it will last.

    I have found a premiere Lennox contractor in my area that's been in business for 54 years. NATE certified. Performed Manual J & D calcs. I've checked with my state to verify their contractor's license as well. Since this contractor is a premiere dealer, they're offering the Lennox 12 year parts & labor warrnty on the furnace and a/c.

    Furnace: 70,000 btu - Total Manual "J" Heat Loss = 46,727

    A/C: 2 TON A/C (2-1/2 TON COIL) - Total Manual "J" Heat Gain = 18,470 btu's

    I was considering a Lennox XP15 heat pump but decided against it for the following reasons:

    Greater cost up front

    Keeping snow away from it in the winter (location would be below a deck where snow piles up after shoveling off deck)

    The air coming out of indoor vents from a heat pump is cooler than the warm air from a gas furnace

    Concerns that the heat pump will be running year round thus making it more likely to break down sooner than using a furnace & central a/c.

    I used this website to help determine my utility costs.

    Your cost for a gas furnace would be $ 521 per year.
    Your cost for an electric heat pump would be: $ 480 per year.

    These costs are based on the following assumptions:

    1. The heated area of your house is: 1550 square feet.
    2. Your house's insulation is: More than typical. R57
    3. The winter heating load hours for your location is 2443 hours.
    4. The efficiency (AFUE) of the gas furnace is 95%.
    5. The gas furnace does not have a standing pilot light.
    6. You pay 77 cents per Therm for natural gas.
    7. Your monthly customer charge for natural gas is $5.00.
    8. The efficiency (HSPF) of the electric heat pump is 8.7.
    9. You pay 7.8 cents per kilowatt hour for electric power.
    10. Your monthly customer charge for electric service is $3.

    When calculating my cost per therm, I only used the cost for Nov 2009 - March 2010 as those are the primary heating months in my area. Cost per killowatt hour was the same for the past 12 monhts.

    I am aware of the federal tax credit, state rebates, local utility rebates and manufacturer's rebates for my furnace & a/c.

    Does anyone have an opinion on any of these Lennox products? Any advice you'd like to share?

  2. #2
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,748
    G71 and XC15 are both very good units, you should get many happy years service from both of them.

  3. #3
    Join Date
    Jul 2004
    Location
    NW Arkansas
    Posts
    1,288
    Looks like a great dealer and the equipment is top of the line. If you get a lot of sun in your area the furnace and I am pretty sure the condenser can be run using Lennox solar panels. The panels are new for Lennox. I have been out of residential since 2004 but my good friend runs a Lennox premier dealership. He got pricing for the solar panels last month and has bid a few jobs using them.

    I will be adding the panels to my system this Summer. The panels can be installed in stages.
    Signature on hold. Trying to find a real Jefferson quote I like. Others here have bogus Jefferson quotes too.

  4. #4
    Join Date
    Dec 2009
    Location
    Seattle, Wa.
    Posts
    142
    The XC15 is being discontinued and will be replaced by the XC17, which will be a communicating A/C. I would also look at the SLP98V which will replace the G71MPP and also be a communicating furnace. These announcements are effective June 1, as I understand it.

  5. #5
    Join Date
    May 2010
    Location
    Northern Utah
    Posts
    18
    Quote Originally Posted by t527ed View Post
    G71 and XC15 are both very good units, you should get many happy years service from both of them.
    Thank you. I do too.

    Quote Originally Posted by wgrr View Post
    Looks like a great dealer and the equipment is top of the line. If you get a lot of sun in your area the furnace and I am pretty sure the condenser can be run using Lennox solar panels. The panels are new for Lennox. I have been out of residential since 2004 but my good friend runs a Lennox premier dealership. He got pricing for the solar panels last month and has bid a few jobs using them.

    I will be adding the panels to my system this Summer. The panels can be installed in stages.
    I’ve seen information on the solar powered heat pump. I don’t want to deal with panels on the roof and the up front cost.

    Quote Originally Posted by Paul12644 View Post
    The XC15 is being discontinued and will be replaced by the XC17, which will be a communicating A/C. I would also look at the SLP98V which will replace the G71MPP and also be a communicating furnace. These announcements are effective June 1, as I understand it.
    The differences I could find between the XC15 & XC17 were:

    XC15 - Factory installed Lennox system operations monitor; 63 dB

    XC17 - Up to 18 SEER; If frost, ice or dirt builds up on any part of the fan assembly, the motor automatically compensates by operating at a higher starting torque & alternating the rotational direction of the fan to allow the angled blades to break up the debris; 62 dB

    What do you mean by communicating a/c & furnace?

    1800-9 Lennox confirmed the June 1st availability of the SLP98V. There is very limited online information available for the 98% efficient furnace right now. Even if the SLP98V were available today, I doubt I’d buy it. The G71MPP36B-070 seems efficient enough for my needs and cost is high enough as it is.

    Thanks for your info.

  6. #6
    Join Date
    Dec 2009
    Location
    Seattle, Wa.
    Posts
    142
    Communicating means that there is a printed circuit board with intelligence in the outside A/C or heat pump that "talks" to the furnace pc board through a system bus with a protocol that can alert both devices with pertinent information, like model number, serial number, revision level, and advanced diagnostics to help troubleshoot system problems. The thermostat inside the home would also be a communicating device that talks to the furnace board and permits fault information to be displayed on the thermostat.

    If everything is working correctly, the information supplied should lead the technician to more quickly diagnose and repair existing problems. This is new for Lennox so there may be some bugs to be ironed out before everything is working correctly.

  7. #7
    Join Date
    May 2010
    Location
    Northern Utah
    Posts
    18
    So it sounds more like a diagnostic tool rather than anything a typical homeowner would know about. I could see how Lennox repairmen would like that.

    I'm getting the 12 year parts & labor Complete Care Plus Warranty. I'm hoping that will cut down on most of my servicing/repair costs other than routine maintenance.

  8. #8
    Join Date
    Dec 2009
    Location
    Seattle, Wa.
    Posts
    142
    The other advantage to it is that it only requires 4 wires to be run from the thermostat to the furnace. For the same functionality a non communicating furnace would require many more wires.

    I also have recently installed the G71 with an XP14 heat pump and opted for a ten year parts and labor warranty.

  9. #9
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,748
    as small as your loads are the SPP and XC17 would be overkill.

    the G71 and XC15 have been around long enough with no problems that i would just stay with them.

    just make sure installer is using a 2 stage thermostat so you get full benefits of the G71.

  10. #10
    Join Date
    May 2010
    Location
    Northern Utah
    Posts
    18
    Quote Originally Posted by t527ed View Post
    as small as your loads are the SPP and XC17 would be overkill.

    the G71 and XC15 have been around long enough with no problems that i would just stay with them.

    just make sure installer is using a 2 stage thermostat so you get full benefits of the G71.
    My proposal says White Rogers Digital Programmable Thermostat. Doesn't say single or 2 stage. When searching online for White Rodgers products, I don't see a 2 stage thermostat. I'll call my dealer and inquire about a 2 stage. Thanks for the advice.

  11. #11
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,174
    WR makes 2 stage, and multistage thermostats.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  12. #12
    Join Date
    May 2010
    Location
    Northern Utah
    Posts
    18
    I went searching online for the difference between a single stage and 2 stage thermostat. This is ultimately what I would like out of the performance of my furnace:

    In the morning when it first turns on, when there is a temperature difference of many degrees between actual and desired temperature, it will kick in high heat immediately warming the house much more quickly;

    If there is a difference of one degree or less between actual and desired temperature, it will run at low heat only

    Would this be achieved by a single stage or 2 stage programmable thermostat? Does this also depend on the wiring supplied in/on both the furnace and the a/c unit?

    The White Rodgers 2 stage thermostats I've seen online state that their application is for "conventional or heat pump." Does conventional mean natural gas furnace?

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,174
    Conventional would be gas/oil furnace.

    A 2 stage stat is what will do what you want.

    A single stage stat, would require the furnace to use a timer.

    You will need the appropriate amount of wires that the thermostat needs.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

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