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New Carrier Furnace

squibby
9 years ago

HVAC novice here so I appreciate everyone's guidance in advance ...my questions seem pretty general so perhaps this can help others in the process.

Here are the facts for my 1 zone system in NJ (2600 sq ft):

* Original York gas furnace is 16 years old, single stage, 80% AFUE, and 140k BTU's (input). It works but cycles on and off often, and maintenance checks show deteriorating performance each year. Had water leakage underneath recently, which I'm told was due to a busted condensate pump which needs replacement. Not sure if this affected the furnace in any way. I'm ready for a new one although I do wonder if I can squeeze more usage out of it.
* Humidifier is attached but I have no idea whether it works properly, nor would I notice whether it is on or off from a comfort standpoint as I can't exactly tell the difference between wet or dry air.
* 5 ton Carrier Performance AC is 7 years old. Maintenance performed annually and no issues to date.

I contacted 2 authorized Carrier dealers for furnace quotes. No Manual J calcs performed although I didn't ask. Both recommended 120k BTU's which would put output higher than existing furnace (115-118k @ 96-98% efficiency vs 112k at present based on 80% efficiency). Quotes were comparable in general, with one major difference. Dealer A (who installed the AC condenser and currently services it + the furnace) included new supply and return plenums for an added cost of $950. Dealer B's quote does not specifically mention new plenums so I assume they are excluded. Obviously Dealer B's quote is more attractive because of this.

Questions I have on this project are as follows:

1. Are new plenums recommended, in which case I assume Dealer B plans on using the existing ones? If not required, then is Dealer A trying to burden me with an unnecessary cost?
2. Are there any concerns I should be aware of with upgrading from 80% to 95%+ from a fit-out standpoint? I've never complained about gas bills or comfort but perhaps I don't know what I'm missing and I realize a 90%+ furnace is recommended for the Northeast. Is it a no-brainer to go high efficiency?
3. Is a Performance furnace the best match for a Performance AC or is Infinity a better option based on its increased performance & features? I'm told an Infinity furnace and Performance AC won't be able to "talk" to each other but not sure what that means. Incremental cost for Infinity vs Performance is ~$800 but is the 59TN6 or 59MN7 a vast improvement vs the 59TP5? And with a nominal cost difference after rebates for the Infinity options, which is the better choice of the 96% and 98% furnaces, i.e. is the gas modulating option a nice to have? I tend to buy more than I need when it comes to other products but would like to avoid that here.
4. Other than less frequent replacement of filters, what is the advantage of a 2210 media cabinet ($250 cost) vs sticking with the 1" filters I use now? What is the recommended or max MERV rating for the 4" filters?
5. Is an Infinity air purifier overkill beyond a media cabinet or is there an added benefit that is worth the $1,250 cost?
6. Do humidifiers fail and should I invest in a new one now with the new furnace? The existing humidifier is anywhere from 8-16 years old.
7. Is an additional 5 years of labor warranty (for a total of 10) worth a cost of $350? I'm usually not a fan of extended warranties and have had minimal issues beyond maintenance for my inferior York furnace.
8. Is the Infinity thermostat the recommended match for an Infinity furnace vs using another highly rated (and less expensive) thermostat?
9. Does 120k BTU's sound appropriate or too much? Do I demand a manual J calculation and can it be manipulated by the dealer to produce a desired result? (i.e. 120k BTU for simplicity, like the original quote) How reliable is the calculation and is it required for rebates/permits? While I imagine it takes time, why would authorized dealers not do it automatically if it should be standard practice?
10. How to make sense of all the rebates offered and when they end? (dealer vs Carrier vs NJ Clean Energy) Is there historically a best time during the year to buy a new furnace from a total cost standpoint or does it not really matter? Given the added rebates for whole systems, is there any advantage to scrapping my 7 year old AC and upgrading o an Infinity model to have a matching system? Seems unnecessary but not sure of the expected life as my previous York condenser only lasted 9 years.

While replacing the furnace, I may be interested in adding ducts / dampers to my finished basement for heating purposes. Currently I have a space heater which works fine but is loud and blows hot so the space is usually not the most comfortable. Cost of ~$3k surprised me and I'm not sure if there are better/cheaper options or if I should leave well enough alone. I have a combination drop/drywall ceiling so I don't know what kind of mess would be made in adding ducts. Anybody do this with success?

Lots of questions I know. THANKS for all advice!

Comments (4)

  • mike_home
    9 years ago
    last modified: 9 years ago

    Where in NJ are you located? If you are in or near Mercer county I can recommend a Carrier dealer who will properly size your equipment with a load calculation.

    You have a lot of good questions. I will try my best to answer them briefly.

    1. The plenum should only be changed if it needs to be modified to accept the new furnace.

    2. It is a no brainer to go to high efficiency.

    3. Both the Infinity and Performance furnaces are very good. The 59MN7 is best since it can modulate to many speeds to maximize comfort. You will have to decide whether some comfort features are worth the extra cost.

    4. I recommend the 4 inch media filter. It lasts longer is less restrictive to air flow. A MERV 8 filter is fine for most people.

    5. Electronic air cleaners are overkill.

    6. The existing humidifer could be used. It can be replaced in the future when it fails.

    7. Carrier provides a one year labor warranty. You need to find out who is providing the additional labor warranty and if there any maintenance contracts required.

    8. If you get an Infinity furnace then you should get the Infinity controller.

    9. A 120K BTU furnace is very oversized for your house and climate. I would think an 80K BTU furnace at 95% efficiency would be appropriate. You need to find a contractor who will do a load calculation to confirm the size. I also think the 5 ton AC is oversized.

    10. The best time to a HVAC equipment is early spring and early fall. This is when Carrier and other brands offer rebates. I recommend not buying now if you can hold off until spring.

    I am not a fan of the NJ Clean Energy rebate program. You are usually quoted inflated prices and then get money from the state. The savings are small if any. The 10 year interest free loan may be worth it to you. You have to decide after you run all the numbers with and without the program.

    Running a duct in a basement is relatively. I am not sure why you were quoted $3K. This this include opening walls and repairing sheet rock?

  • squibby
    Original Author
    9 years ago
    last modified: 9 years ago

    Hi Mike,

    Thanks for the quick and through reply. Some follow-up questions:

    I'm in Hunterdon Cty so would the Mercer dealer travel here? I would like to have the installer perform the annual maintenance so I'd want to make sure travel wasn't an issue, not to mention I'd need prompt service if I had an emergency.

    I'm still foggy on the new plenums, which represent a significant gap between the 2 quotes. Can the salesman (former repair guy) not tell beforehand whether they need to be modified to accept the new furnace? Although perhaps Dealer A felt yes and Dealer B no hence the quotes I received. For most installs, are the plenums typically kept or replaced? If I were to go with Dealer B, might he tell me mid-job that I need new plenums?

    How to tell if/when a humidifer has failed? It doesn't seem to make much noise from what I can tell.

    I was quoted a 5 year Carrier labor warranty? Is that not accurate?

    The 5 ton condenser replaced the original. Do builders usually just throw a big size in without consideration as to whether it is too much?

    How much better might the Carrier rebates be in the spring? i'm not even sure if the 2014 rebates have expired.

    The NJ Clean Energy rebate (WarmAdvantage) looks like $500 for 95%+ and Energy Star qualified. Isn't that free money to take advantage of or is 0% financing some sort of alternative? I wasn't looking to finance.

  • squibby
    Original Author
    9 years ago
    last modified: 9 years ago

    Trying to get more details on the basement install procedure that makes up the $3k quote. What is the standard process for adding heat to the basement via new ducts?

  • mike_home
    9 years ago
    last modified: 9 years ago

    You may be within the service area of the Carrier dealer I use. Send me an email I will provide the contact info. Set your account so that I can see your email address, otherwise I won't be able to reply.

    I participated in the Warm Advantage and Cool Advantage rebates 5 years ago. It is free money if you qualify. The program I was referring was the one where you have spend a lot of money upgrading insulation and sealing in order to qualify for the rebates.

    You may have misunderstood the labor warranty. The dealer may provide the first 5 years as part of his standard quote with an option for another 5 years. You should ask about this.

    The rebates of an Infinity furnace and AC are $800-$1200. But you don't get a new condenser it will be less. Be aware the dealer has to pay half the rebate cost so you may or may not see the full amount taken off your quote.

    Going up in size in a condenser gets to be expensive so a builder would typically not oversize a condenser. If your house has vaulted ceilings, skylights, and a lot of windows facing south and west then a 5 ton may be appropriate. The problem is most houses don't have the duct work big enough to handle the air flow required for a 5 ton condenser.

    The salesman should be measuring the plenum to see if it is big enough to handle the proposed furnace. The 120K furnace at 95% will provide more heat than your current 140K furnace at 78%. The plenum discussion is a moot point since they are both quoting a furnace that is too big!

    Did you tell them the current furnace short cycles? If you did and they ignored it then you should be talking to more contractors.