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  1. #1

    Installer questions

    First, I'd like to thank everyone for their help before. Reading these forums has been a great source of information. I do have a few more questions though.

    We received 3 bids so far. Two from Lennox dealers and one from a Trane dealer.
    After talking with the Lennox dealers, we felt very confident in their companies and ability to properly install our new furnace. Neither ran a load calculation but we figured that was just because we are going to install just a new furnace and not a new evaporator coil or condenser. Both companies tried to steer us away from adding a duct out to our garage and both said upgrading from a 3-ton to a 4-ton furnace wouldn't be beneficial. One even noticed we had a vent in our return air duct up in the attic. He said that was a bad thing. They both obviously had nothing but good things to say about Lennox.

    The Trane dealer was a different story. The initial bid was over the phone, we were told adding a duct to the garage was doable, and going up to a 4-ton unit would be ok. The Trane dealer is a member of the BBB but not a member of ACCA and they have been around since '62. I think overall they are good and honest company and would probably install the furnace correctly.

    My questions are:
    1. Should we steer clear from a company that says it's ok to add a vent to a garage and increase the furnace tonnage without adding to the AC?
    2. Does the furnace and AC size have to match to properly heat/cool a house?
    3. I've read more good things about Trane compared to Lennox on this board.
    Not to start an argument here but in this case would a Lennox be a better choice?
    4. Do you need a 2-stage thermostat for a 2 stage, variable speed furnace?

    Thanks

  2. #2
    Join Date
    Jan 2003
    Location
    Kansas City
    Posts
    1,482
    1. Steer clear of anycompany that bids a system over the phone.
    2. A/C, coil, blower motor and furnace need to match each other and the needs of the home
    3. Major manufacturer + warranty + competent installation = best system
    4. You do not NEED a 2 stage t-stat, but system operates more effectively this way than with timers.


    p.s. All manufacturers have issues from time to time. I could list several from any manufacturer in our area. The key is how the manufacturer and contractor services the customer with these issues.

  3. #3
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,708
    if your garage is still used as a garage it should NEVER have any duct tied into the house system.

    unless they have a crystal ball how the he!! do you quote a job like that over the phone?

  4. #4
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,917
    1. Vent to garage is very dangerous. We refuse to do, probably against code. Very great risk of allowing CO into the house when the car is started.

    Now, understand "tonnage" and furnaces. All that means is the blower is capable of moving 4 tons (1600 CFM) worth of air on high with reasonable duct static pressure. If you have a 3 ton A/C, it isn't out of line to go with a "4 ton" blower BUT a GOOD dealer, and few bother, would take a static pressure check, look at the blower specs and set the cooling speed properly. Almost all we see around here leave on high, move too much air and reduce moisture control. Only drawback of having a 3 ton drive on a 3 ton air is that many duct systems are restrictive and especially with a decent filter, you'll not move 3 tons of air reducing capacity.

    2. The size of both should match the needs of the house. There is no match to each other expect for the furnace moving the right amount of air for the size of the cooling unit.

    3. Everyone has their own favorites. Properly sized & installed, both will be fine. Now, your Lennox dealer didn't size per heat loss. How is he sizing? Guessing? Basing it on the old one which may well be oversized?

    4. Unless you want constant cycling in cold weather instead of nice, gentle warmth, you need a good 2 stage stat.

  5. #5
    Thanks for the replys. With additional questions.

    Both the Lennox dealer and the Trane dealer have 10 year p&l warranties. The Lennox dealer requires you to buy their service plan though.

    Every dealer has based their bid on the size of our current furnace. No one has taken the time to see if it may be too small or too large. As a newbie questions, if the temperature feels ok how can you tell if a system is oversized or undersized? How can a dealer tell? If oversized, are you wasting energy? If undersized are you not getting the proper force out of the vents and air recirculation?

    We will be adding either a Lennox or Aprilaire media air cleaner. Based on what BaldLoonie said previously about ducts and filters would this be a reason to consider upping to a 4-ton unit?

    Also, what distinguishes a good installation from a bad one? Briefly, what are the steps in a thorough installation and post installation?

    Thanks the help. I think I'm finally starting to get the basics on how this works.

    Thanks

  6. #6
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by Lisa from MN View Post
    My questions are:
    1. Should we steer clear from a company that says it's ok to add a vent to a garage and increase the furnace tonnage without adding to the AC?
    2. Does the furnace and AC size have to match to properly heat/cool a house?
    3. I've read more good things about Trane compared to Lennox on this board.
    Not to start an argument here but in this case would a Lennox be a better choice?
    4. Do you need a 2-stage thermostat for a 2 stage, variable speed furnace?

    Thanks
    1- Why do you want to add a vent to the garage? I am not sure if's state or city code, but here in Rochester, you can NOT have a vent in the garage with CO2 risk.

    Do you current have A/C?

    2- Yes, dealer should do a Manual-J load calc on the home for the right sized furnace.

    3- As Bald said, everyone has Faverite brands. With my experince, Lennox is harder to get parts down here in Rochester, and there is a Trane Wholesaler in town, so getting parts is not an issue. (I don't know where you are from )

    4- Two stage T-stat gives you COMFORT. It will be wll worth the extra money for this type of t-stat. And if wire is an issue, Honeywell has an IAQ T-stat that only uses 3 wires.

    Every dealer has based their bid on the size of our current furnace. No one has taken the time to see if it may be too small or too large. As a newbie questions, if the temperature feels ok how can you tell if a system is oversized or undersized? How can a dealer tell? If oversized, are you wasting energy? If undersized are you not getting the proper force out of the vents and air recirculation?
    Not really a good ideal to go by current system. I replaced mine 2 years ago, I did the load calc. I replaced an old 115,000 BTU to a 60,000BTU 2-stage Trane.

    I am sure you temps in the home feels ok. But are all the room pretty equial ?

    When we get a good cold snap, say -20 outside, does your furnace cycle on and off, or runs prettty steady?

    And yes, if you are oversized it cycling on and off too often, and the furnace is not going to get a chance to get it's full effcency rating and wasting gas reheating the heat exchanger.

    In your car, you get better milage driving downtown Mpls at all the stop angd go? or crusing down the highway?

  7. #7
    We were thinking about a vent in the garage for our animals but we've been told it's against code. Makes sense now.

    The Lennox dealer said they keep parts on-hand so I don't think that will be an issue. I had some other questions for him so I will ask him about a load calculation then.

    Our current furnace is a 22 year old 3-ton Carrier model DH58. According to the brochure I saw it's suppose to 80% efficient and was the Carrier top of the line back then. I'm assuming though there is a big difference between an 80% from 1985 and an 80% from today.

    Rooms are pretty equal except for the farthest room. It does get colder there compared to the rest of the house. Is this a case of improper furnace size and duct work or because it's on the northern side of the house? The Trane dealer said going to a 4-ton would help.

    Our current furnace definately cycles on/off. I would say probably 5 or 6 times an hour. I thought this was normal for a furnace this old as opposed to one being improperly sized. Would this still be an indication of an oversized unit?

  8. #8
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    If it cycles that often during the coldest time,indicates it's oversized.

    Ferthest room(s) form the furnace colder,undersized ducts ,or lack of a return or return path from that araea.

  9. #9
    I kept a better track of it last night. With t-stat set at 68 it was 4 times per hour; at 66 it was 3 times.

    The total running time per hour was pretty equal to the down time.

  10. #10
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    So it kept you up all night!lol

  11. #11
    No just while watching tv. It's loud enough so I'd just glance at the clock when I heard it. It was pretty consistent.

  12. #12
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Where is the noise coming from?Return grille,supply ducts,furnace??

  13. #13
    The noise comes from the furnace and the return duct. The supply seems pretty quiet.

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