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  1. #1
    Join Date
    Apr 2013
    Location
    Tennessee
    Posts
    8

    Assisting parent with new unit choice

    I'm helping my elderly parent in Indian River County, FL with an upcoming selection of a new AC unit. Presently there is an AC unit with heat coil strip. It's 20+ years old, still works, but I'd like to replace it before it is critical to do so.

    The house is a 3/2 with about 1,000 sq. feet, hip roof, frame construction. It's 10 miles from the coast.

    I believe the choice will be between going with an AC unit with heat coil strip or a heat pump. The difference in price will most likely determine the decision. The current outdoor unit is on a concrete pad outside the garage with the lines being run across the width of the garage to the thermostat on the combined living room/garage wall. The inside unit is in the garage, again along the width wall. It appears to be a straight-forward installation.

    Since I am out of state (TN), I'm lining up contractors to come once I am in FL. From my reading here, the contractor should do a Manual J calculation to determine the correct size unit. After that my question is what should be on a quote from a contractor? At a minimum, I'm thinking there should be: manufacturer and model #, what work is to be done, if they will pull any permits required, warranty terms, how long for installation, manufacturer rebates along with utility company rebate programs and IRS tax credit, and of course, price.

    Is there anything else I should be on the look out for?

    Thanks for any suggestions.

  2. #2
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Go with a heat pump. In Florida, heat strips should rarely be needed. It should drop the energy use by 1/3 in the cooler months. With such a small house, it shoudl be a pretty small unit. In Florida, humidty is hte ocncern not temperature. The design temp actually isn't that hot, ususally 91-93 for most of Florida. But oversizing will hurt humidity control and make it a lot less efficient and increase wear and tear starting and stopping.

    I think you have it abotu right on your bid requirements. Ideally they should publish the AHRI number as well with the rated effciencies of the equipment.

  3. #3
    Join Date
    Apr 2013
    Location
    Tennessee
    Posts
    8
    I'm not familiar with AHRI numbers; what is that? As to the rated efficiencies of the equipment, do you mean the SEER rating?

  4. #4
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,137
    in a small house like that (small like mine) the question will be
    between a 1.5 ton & a 2 ton system. they are very close in cost,
    so hvac company will recommend 2 tons.

    after doing a load calc on my house, even with upgraded insulation
    in attic & air sealing of house..I went with two ton.

    where I put the upgrade money was in higher efficiency (15 SEER) heat pump
    with a variable speed air handler unit.
    the 'sweet spot' in efficiency in hot humid climates with heat pumps is 15-17 SEER.
    and with the heat pump instead of electric strip as primary heat the
    savings in the winter pays for the upgrade fairly quickly.

    ahri is air heat refrig inst, this is where you take the brand, & model numbers of
    equipment to see if they are a match to provide the SEER, EER and with Heat Pumps
    the Heating Seasonal Performance Factor (HSPF).
    if the equipment isn't a match, the performance of the equipment is lessened.
    the hvac company should but doesn't always provide this info to the homeowner.

    ductwork should be checked, any hot/cold spots addressed & ducts mastic sealed.
    are ducts in attic?

    what do you mean by 3/2?
    you should check the site map for contractors in your folk's area.

    best of luck.

    the winter time savings was amazing...and in the summer I could
    get house to 55% Relative Humidity (RH) with vs ahu alone.
    to get lower..whole house dehumidifier.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  5. #5
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    6,338
    I think 3/2 is 3 beds 2 baths. I agree with erla, wouldn't be a bad idea to have a home energy audit done to see how you could make other improvements that could lower tge size of the equipment, provide better comfort and allow the rated efficiency of the equipment to be achieved.

  6. #6
    Join Date
    Apr 2013
    Location
    Tennessee
    Posts
    8
    Thank you both, erla and jtrammel for your comments. I've made notes on making sure the ductwork is inspected. I hadn't thought of an energy audit. Since this is my mother's house and she is somewhat set in her ways, I'm not sure if she would go for that. I had it done at my own residence when I replaced a system five years ago and thought it was helpful.

    I'll check back here next week once I have estimates in hand. Thank you for the ideas and if you have any other comments that would be fine.

  7. #7
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,234
    Quote Originally Posted by Bnew View Post
    Thank you both, erla and jtrammel for your comments. I've made notes on making sure the ductwork is inspected. I hadn't thought of an energy audit. Since this is my mother's house and she is somewhat set in her ways, I'm not sure if she would go for that. I had it done at my own residence when I replaced a system five years ago and thought it was helpful.

    I'll check back here next week once I have estimates in hand. Thank you for the ideas and if you have any other comments that would be fine.
    What are the FPL bills for last 24 months?

    1,000 Sq. feet with about 130 square feet of glass area?
    West facing amount of glass ___ Sq Feet ?

    Heat loss is probably < 16,000 BTU/hr because Winter Design temperature is 39'F - Vero Beach- Melbourne FL.

    Was house built ~ 1993?
    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

  8. #8
    Join Date
    Apr 2013
    Location
    Tennessee
    Posts
    8
    I've gotten four estimates on units for heat pumps (decided to go with that since that is what is already in the house. I was wrong on the heat coil strip). All contractors are local guys and have been in business for at least a decade.

    They seem to have different ideas on the freon lineset. Presently it is in a chase under the garage concrete. All have said the existing copper lines look good. The house is 23 years old.

    Two companies want to flush out the existing lines.

    One man said their current education stresses putting in a new lineset if at all possible. He proposed running it in the attic, across the width of the garage, through the soffit and down the side of the house.

    The last man said the best way was to pull a new lineset through the existing chase.

    Question: Which way would be best? Have there been problems later down the line if the lineset is flushed?

    The other problem is two of the men have warned me about the XR-13 motor installed in the Trane and some other manufacturers as being problematic. That being said, one quoted me a 2.5 Ton, 14 Seer Trane model #4TWB3030C100A and a second one quoted me a 2 ton, 14 Seer Trane model 4TWB3024C1000A.

    Question: Have there indeed been excessive problems with this motor which I should be concerned?

    The other unit recommended as a step-down from Trane was a 2 1/2 ton, 14 Seer Comfortmaker model #N4H330

    It appears the choice in this area is between Trane and Comfortmaker. Is that particular model for the Comfortmaker a good option for my parent since money is a consideration?

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