There are smaller BTU furnaces availible. 40,000 BTU.
As far as can 1 unit do all 3 zones, yes, but your house may not have the duct work layed out to make that feasable now.
Of course, having 2 or more units gives you the advantage of if 1 breakes down, you have the other ones still working.
if you go with 1 carrier...
you could possibly get away with 1 huge carrier & get an infinity control with it. the infinity control could control dampers if you have them installed for different rooms different times of day, you'll need someone to install these duct dampers, and you'll need to return boots (one on either side of the furnace)
and this all depends on the duct runs in your house, for all i know it may cost you more just for the extra duct work. but your sales guys would give you an idea if you throw that option at them. I don't know if Lennox or York carry a similar thermostat as the carrier infinity.
The only way to size a furnace or AC is to perform Man J heat loss/gain calculations. Otherwise you're guessing at the needs of the the structure and occupants. This and Man D duct evaluations should be done no matter what system option you choose.
Originally posted by benz
I am the original poster...thank you all for your help ... now I have more questions...
As I understand it from what has been posted so far:
1. Coleman 90+ is exact same furnace as York 90+
2. Coleman/York 90+ is as good a furnace as Lennox 90+
3. Lennox costs more
The Lennox 90+ quote is $3,500 more than the Coleman 90+
... so, would you professionals recommend that I go w/ the Coleman
The Lennox is G51MP-36-070; 6200 BTU, 92.1 AFUE
The Coleman 80MBH 90+
Have been led to believe these are comparable furnaces... are they?
We had quotes from 5 different contractors ... all carry different "brand names" ... Carrier, Rheem, Lennox, Coleman, Maytag. These are the 2 best quotes...and more important, I trust the contractors.
I have been agonizing over this decision b/c we have 3 zones and need three furnaces and 3 a/c ... so this is a very expensive venture. Our home is about 3,000 sq. ft ... but the original owner installed upstairs, downstairs, and sunroom zones when he built the house. When we bought the house (17 yrs. ago -house is 22yrs old)we thought that was great... never considering replacement costs.
We have been told that we need three of the smallest furnaces available ... are the furnaces we were quoted the smallest available??? and does that sound right to you?
I have been reading online... and "think" I read that people can have 3 zones in their house but only have 1 furnace... is that possible???
If it is possible, not one of the 5 contractors that came to my house mentioned this to me. Wouldn't it be better (and cheaper) for me to get 1 furnace that can handle all 3 zones ...rather than 3 individual furnaces??
Please advise... I am completly ignorant about this ... and really need some good advice. The cost for the replacement is outrageous... and if we can do better, I would like to.
Thank you for your help!
To help compare the Lennox vs Coleman we would need the model number of the Coleman. Coleman 90+ furnace sizes range from 40k to 120k btu input. I would recomend var spd blower (which has 2 stage heat) for best heat and AC efficiencies.
As stated by others seperate units allow you some comfort conditioning if one should require repairs. Since the house is already set up for seperate systems, The cost of joining them properly as a zoned system from one unit might be close to the cost of replacing all 3 as they are.
Colemanor lennox ??? Zoned or indivisual units
There are several considirations to zone an installation. better and more control that affects efficiency of the system. added cost of the control mechnisms. The knowlegde and ability of the contractor or firm who installs it as with anything. It is a common installation in commercial applications and in recent years zoning has become a larger part of larger residential installations. A 3000 sq foot home is a good candidate for zoning. You can however install zoning to a single unit in this home or you can install zoning in a three system a/c/h application in this home. Cost is always a large factor whether it be the brand and model or the amount of control of the environment you need or want available to you. Utilizing three individual units or systems is good and can be made highly efficient when properly planned and installed and can be very usefull if failure occurres. 1/3 or 1/2 of the home disabled for a period of time can be very satifying during the repair of the failed one or a mainteance issue. It can also be very useful to the homeowner to isolate an area and conserve the expense of running a large single unit when not needed or during low demand periods. The duct system is usally quite differnt for a zoned system and is duplicated for a multiple system applications. Expense of labor for each application is based on the structure of the home and the placement of the indoor units. Strategic planning is a great factor in determining the cost or application of the systems. One can only obtain estimates and request drawings to show how these systems can adapted to the structure of the home. No one that you hire can work for food, so be ready. You may however enjoy a good installation of either type system, comfort as well as control and operating cost. good luck. It might help to know your contractor.