2 stage vs. 3 stage furnace

14 years ago

I have gotten several bids for replacing our furnace and have narrowed it down to the best two.

The first bid is for a Trane 2 stage, variable speed, 95% efficient model. It comes with a new programmable thermostat.

The second bid is for a Carrier 3 stage, variable speed that is also 95% efficient.

I understand that there is a great deal of difference between a single stage and a two stage, but I am unsure if there is a great difference between a two and three stage. The second bid doesn't come with a new thermostat, but the one we currently have is digital and seems to be in good working order. The bids are within $5 of each other. I would appreciate any insight as to which is the better buying decision. Also, I realize that the person who installs the system is the most important component. Both companies have good ratings from the BBB, and the reviews I can find are favorable.

Sort by:Oldest

Comments (6)

tigerdunes
14 years ago
aab

what area of the country do you live?

both of these are nice furnaces. with the two stg XV95 Trane, you need one of the following two stg stats; Trane's 803 or identical HW Vision Pro Mdl or HW Vision Pro IAQ. With the Carrier three stg ICS furnace, you must have the matching Infinity controller-no substitute.

You don't want to cripple either of these furnaces with the wrong stat.

price, warranty, and comfort with the dealer would drive my decision although Carrier with the Infinity controller would be my choice.

what are you doing about either an AC or HP condenser?

IMO
johnax
14 years ago
And don't forget to offer whichever contractor you choose 10 or 20 percent less than their bid, unless the money isn't important to you. The bids aren't scientific - they add a mark-up of around 20% to the equipment, guess-timate the labor, and add a pad to make absolutely sure they come out well to the good and help cover their 'off' days.
If they say 'no' to your offer, ask them to justify it by breaking down material and labor. Then you can have an intelligent discussion about the bid.
Related Discussions
1 stage vs 2 stage furnace with a Heat Pump
Q
Comments (1)
What is the wattage rating of the the low and high stages? I would think the low stage of the electric furnace would be sufficient as auxiliary back up heat. But in your location it can get very cold and you may need the high stage. Can your thermostat control three stages of heat? If yes then you may want to set it as a three stage system (heat pump, 1st stage furnace, 2nd stage furnace). I am not sure how this works with lock out temperature settings. Call Honeywell for guidance.
...See More
Carrier Furance: 2 Stage VS 3 Stage
Q
Comments (5)
Tigerdunes, You know much more about heat pumps than I do. So please educate me. I thought in a dual fuel system set up, either the furnance or heat pump is operational. The switch over is set by a predetermined lock out temperature. For example if the lock is set at 40 degrees, then heat pump would take care of heating needs above this temperature. For temperatures below 40, the furnance takes over. Therefore in the dead of winter, when you several days of temperture below 40 degrees, why wouldn't you want the comfort of a 3 stage furnace? Am I missing something?
...See More
2-stage/2-zone vs 1-stage/1-zone & foam vs fiberglass ?
Q
Comments (12)
Those prices are high. When you pay that much for HVAC, it really makes sense to superinsulate and then just use electric baseboards. Even 1/2 of $17k would get the structure to a level where you could fully heat with electric baseboards for what you want for $100 a year. If you need a/c, do a minisplit for $4000 installed and that $100 goes to $30. By superinsulate - sprayfoam is not it. In your climate, you want R40 walls which is achieved by 12 inch thick walls with cellulose/fiberglass or 3-4 inches of rigid foam on top of 2x4 wall. Sprayfoam has its place but filling a cavity with it is not what it is best for. Are you really looking at R20 walls? Is that even code? Or is there rigid foam that you have also? There are no drafts in a modern wall - fiberglass or not. $8k for sprayfoam is a waste. If it is 2 inches of rigid foam on the outside - then it is not. My walls in NC are zip R3 over fiberglass bibs in 2x6. The small amount of rigid foam just helps with the thermal bridging of the framing. The bibs fill voids much better than batts. It is blown in. We have foam in small areas that bibs would not work with. I think $10k did our 3800 sqft house (not counting the zip R which was $3k upcharge over zip). I would think you would want R-80 in the roof which is probably best achieved by rigid foam over the sheathing given the rafter space needed. Or you could just do code minimum and minisplit with electric baseboard back up it since it isn't full time use.
...See More
Central TX - Heat Pump vs. AC/Furnace (Propane) & 2 Stage vs. Single
Q
Comments (8)
Propane has 91K btu's per gallon input, Electric has 3400 Btu's per kilowatt. Propane gives you 72,800 btu's output at 80% efficiency. Electric aprox. 3400 Btu's output per kilowatt, (100%) with only a small amount lost. 72,800 btu's divided by 3400 btu's = 21.4 kilowatts to equal 1 gallon of propane. The average cost of 1 kilowatt in Austin - $0.1142 cents, times 21.4 Kilowatts equals $2.42 for electricty and little more expensive then propane at $2+ per gallon. But this will change drastically if Biden does ban fracking as he stated. But then what happens to the price of electricity? It's a guess, and having the ability to switch between the two may be a valuable option in the near future. But the cheapest option with a stable price for ever would be to capture the heat in the sun with active solar collectors to heat water (not to be confused with solar panels to produce electricity), and store it in insulated underground tanks to use for the winter. After the initial investment it would cost you a few dollars a month in electricity to run circulation pumps, and you could even get the electricity from solar panels for that. They do it in Alaska for building bigger than yours, easy and simple, only problem is getting insulated storage tanks in the 5K to 20K gallon range. I'd do it in a heart beat if I had some really big tanks, I have the land, backhoe and the solar collectors, 9 of them 5' x 9', salvaged from a $35,000 government subsidized program project in the late 70's. (The government loves wasting other peoples money.) Johnson controls started a line of HVAC equipment called champion about 6 years ago. Parts?
...See More
baldloonie
14 years ago
It would be very sad if a Carrier dealer was pushing the 3 stage with existing stat. They should be used with the Infinity control!!!!!

Like tiger said, the XV95 should have a good 2 stage stat on it as well.
aab99b
Original Author
14 years ago
Thank you for all of the help and advice. I didn't know the thermostat was such an important component.
I live in Pittsburgh, PA.
aab99b
Original Author
14 years ago
We have a Trane AC already installed. It is an older model, but still functioning fine, and doesn't get too much use.
seniorscoot
14 years ago
I'm not in hvac, but johnax is right. I always try to guess high on the labor just in case I run into something unexpected, which usually happens. You never know exactly what you're gonna run into. It's not as shady as he makes it sound. I plan for everything going smoothly and add a couple hours because nothing ever goes exactly to plan.

Here is a link that might be useful: Furnace filters

2 stage vs. 3 stage furnace

Comments (6)

tigerdunes

johnax

Related Discussions

baldloonie

aab99b
Original Author

aab99b
Original Author

seniorscoot

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

2 stage vs. 3 stage furnace

Comments (6)

tigerdunes

johnax

Related Discussions

baldloonie

aab99bOriginal Author

aab99bOriginal Author

seniorscoot

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

aab99b
Original Author

aab99b
Original Author