Heating, Air Conditioning, Fridge, HVAC/New HVAC


QUESTION: I am replacing a 20+ year 5 ton airhandler/heat pump. I am considering converting to a gas furnace with air conditioner as our city is offering up to $1400 rebate for the furnace and $700 for the AC. I am also getting a gas hot water heater so the piping will already be done. I live in Tallahassee, Florida (weather is mostly hot but it does get quite chilly at times). I am in the process of getting estimates from contractors and one thing has me stumped. I have had 4 estimates and 3 of them have said to replace with the same size unit and one contractor said I absolutely do not need 5 ton and he recommends going with a 4 ton 2 stage system (Tran). When I questioned him on this he said it was based on his load calculation. WHich he did send to me upon request. None of the other contractors have even mentioned doing a load calculation. (And even if I got it I probably would not understand it). (My home is approx 2600 feet, I have good attic insulation, double pane windows and lots of shade trees). What questions should I be asking the contractors? Is the guy recommending the 4 ton right? I appreciate any help.


Buy your own heat loss/heat gain calculations for $50.00 at hvaccomputer.com and see what you really need.The other three should have done a load calculation, that would be the proper thing to do.You can contact the other three and ask them why they never did one.Also see what all four contractors offer for labor warranty, typically it's one year.Labor warranties are very important.Get all your warranies in writing, parts,compressor,even the thermostat,They all start when the system is first placed in service. Also your existing A/C at over 20 years old the circuit breaker for the outdoor part may be oversized ,amperage wise for the newer more energy efficient units, as an example if you currently have a 40 or 50 amprege. breaker for the outdoor part the new 4 or 5 ton unit may require only a 30 or 40 amprege rated breaker. At the outdoor unit electrical data plate on the new and old unit it will state the " maximum overcurrent breaker" size. You are not suppose to exceed that rating.So that may or may not have been overlooked by all the contractors when they gave you a bid.( certainly it will affect the bid price if it was overlooked )You can also consider a hybrid system, a gas furnace and a heat pump, with an outdoor sensor/t-stat that you set at a particular OD temperature. Anything above a certain OD temp. the Heat pump runs, below a certain temp. the gas runs.

---------- FOLLOW-UP ----------

QUESTION: I have narrowed down the quotes to two and would like your opinion:

1) American Standard 5 Ton 16 seer
Furnace: AUD2d120B9V5 (2 stage heat, variable fan)
Condenser: 4A7A5061E1
Warrenty: 10 Yr labor/parts/compressor

2) Trane 4 Ton 14.5 seer, 12.0 eer
Furnace: TUD2C100A9VV5VB
Condenser: 4TTR5048E1000A
Warrenty: 2 yr labor/10 yr parts/compressor, limited lifetime  heat exchanger

The install for both is the same EXCEPT #2 identified the following that he will fix: replace 2 damaged flex lines, install manual air volume dampers in all supply ducts to balance , increase one return duct from 14 to 16, seal all duct connections with mastic.  and #2 states his flue install will include roof flashing and vent cap

My home: 2618 SF, Attic insulation R-30, Shaded lot.
Both contractors did load calcs and came up with different values...
The cost of the two systems is within $500. However, cost aside, I would like to know which system will function most efficiently and which is sized correctly for my house. (Layout attached - A & B are under heat/air, C&D are not)Also, should I be concerned that #1 did not identify any issues with the duct?
Thank you!


Both furnaces have a limited lifetime warranty on the HX. You mentioned only the Trane.Balancing dampers are a nice feature.I would have bought the heat gain/heat loss calculation as I suggested and do your own accurate calculations, to answer exactly what size you need.I can not tell you which size is correct for your house 100%.At face value, I like the 4 ton unit due to the 10 year labor warranty, dampers install, sealing,flex duct replacement and a larger return ( if it's actually needed ).Of course if this company goes out of business in 2 years that labor warranty is void. Doubt it's transferable. I would ask this Question to the contractor. What happens to the 10 year labor warranty if you go out of business?? Companies go out of business all the time, long and short established companies. Flex duct and manual balancing dampers are minimal cost items for the contractor. Also mastic sealing is more labor intense than cost of the paste.

If you actually need five tons I would ask the other company to do the same as the the #2 Company. Replace the flex duct and add manual balancing dampers and seal main duct line for a minimal add on cost , in order to get the contract. All the parts are minimal cost to a Contractor.

I  find it hard to believe your city is offering up to $1400.00 rebate to convert to a gas furnace that's only rated at 80% efficient.( Both quotes you mentioned are  80% furnaces.) In my state they are giving $750.00 rebate but that is for 90%+ condensing furnaces and the goverment is adding another $150.00 if it's over 95%.They have to be energy start rated furnaces to get the rebate. 80% furnaces are not energy star rated like the ones they are quoting you.

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40+ years diversified experience.An HVAC/Refrigeration Self Employed Contractor since 1986. NATE Certifield. Answer questions pertaining to Residential and Commercial Air Conditioning , Warm Air Heating, Heat Pump systems.Mechanical and Electrical troubleshooting of these systems.Be as detailed as possible when describing problem.Packaged unit or split systems.No appliance questions.


Installation and Troubleshooting, Mechanical and Electrical, in following areas, Refrigeration ( Walk In and Reach In Coolers and Freezers ) Commercial Roof Top and Packaged Heating/Cooling ( Natural Gas,Propane, Electric, and Heat Pumps ) Computer Room Air Conditoning Systems,Commercial Residential Packaged and Split Systems Air Conditoning and Heat Pumps.Warm Air Oil , Natural and Propane Gas Heating systems.

Graduated from Private Technical School in 1975. An HVAC/Refrigeration Contractor . Have Unlimited Heating/Piping and Cooling Contractor License.Limited Sheetmetal Contractors License.NATE Certifield. York Certifield Master Heat Pump Technician 1986. Served 33 years combination Active Duty Air Force , Air Force Reserves and Air National Guard in the HVAC/Refrigeration Shop/Mechanical Shop. Troubleshooting/Installing HVAC/Refrigeration Equiptment Worldwide. Retiring in 2003 as a Senior NCO ,and a Mechanical Superintendent.

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