Results 1 to 9 of 9
  1. #1
    Join Date
    Aug 2007
    Posts
    273

    Carrier expert advice needed-infinity A/C 17 seer vs. 21 seer units?

    My contractor has suggested the 17 seer retrofit infinity A/C unit instead of the 21 seer version. Apart from a little less expense is there any reason why the 17 seer model would be preferred, My contractor maintains that the added seer would not be obtained because of my old house etc.I have seen some comments on this board suggesting that in some applications the 17 seer model would be preferable. I live in Washington dc, hot humid summers. in a house that was built in the 1930's with a forced air system. Thank you all for your help. I apologize for the volume of my questions but here is so much to consider once you get involved in a retrofit. thanks again all.

  2. #2
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Seer rating is not effected by the age of the home,it is effected by the install.A poor duct system,if you have one,will effect either the same amout.

    Only advantage to the lower SEER model is that it's low stage operation is less capacity ,so it will run longer in low stage ,and dehumidify a little better in the cooling season.

  3. #3
    Join Date
    Aug 2007
    Posts
    273
    Ever thing being equal would you recommend the extra cost of the 21 seer system in my situation. Would the scroll motor be a big benefit? which would you pick. i think duct size was an issue picking the 17 seer system thanks for the help

  4. #4
    Join Date
    Apr 2007
    Location
    Derwood, Md
    Posts
    142
    Being in the DC suburbs we selected the 17 Seer unit and couldn't be happier. In my opinion it is better because it is closer to 60/100 while the scroll is running closer to 80/100. In our climate we don't run the AC enough to make the 21 worthwhile. In my case for this year, first season it ran 380 hours on low and 170 on high.
    Make sure they don't oversize the unit.

  5. #5
    Join Date
    Aug 2007
    Posts
    273
    THANK YOU FOR YOUR RESPONSE I live in a smallish 1930 center hall house of approximately 2700 feet of living space over two floors and a finished basement contractor calling for 4 ton unit --sound right? Also what type of furnace did you purchase.

  6. #6
    Join Date
    Apr 2007
    Location
    Derwood, Md
    Posts
    142
    Quote Originally Posted by ron3637 View Post
    THANK YOU FOR YOUR RESPONSE I live in a smallish 1930 center hall house of approximately 2700 feet of living space over two floors and a finished basement contractor calling for 4 ton unit --sound right? Also what type of furnace did you purchase.
    The unit I have cools 2500 sq ft over two floors and a 1500 sq ft basement. I actually went from a 3.5 ton unit to a 3 ton unit. This was based on a manual J calc. We got the 95% Bryant Evolution System 80k btu, it replaced a 100k 17 year old 60-65% unit.
    Did do the heatpump analysis and at 12 cent electric and $1. gas it did not make sense.

  7. #7
    Join Date
    Aug 2007
    Posts
    273
    Is your house well insulated and does it have double pain insullated windows etc.? Mine is from the 30's and has almost no insulation etc. thanks ron

  8. #8
    Join Date
    Apr 2007
    Location
    Derwood, Md
    Posts
    142
    Quote Originally Posted by ron3637 View Post
    Is your house well insulated and does it have double pain insullated windows etc.? Mine is from the 30's and has almost no insulation etc. thanks ron
    Double pane replacement windows and relatively well insulated. You might consider doing the same. Biggest payoff.

  9. #9
    Join Date
    Nov 2006
    Location
    TX
    Posts
    7

    Agree with above

    I think you need to get an energy consultant to verify the
    insulation values of the ductwork and ceiling and make sure
    all the glazing is double or triple pane. Seal plumbing, ducts/registers
    and electrical penetrations. Repair any old or damaged weather
    striping so that the heat gain/loss is minimized in addition to
    adding heat/cooling. This seems to always get overlooked in
    older homes, upgraded HVAC and added or remodeled rooms.
    Your local utility may provide this service free or at a nominal
    charge or they may provide a list of certified contractors.
    Also have a Manual J and Manual D done to verify sizing and layout
    of ducts and HVAC.

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