Furnace Price - Help in Picking correct one

subkanDecember 23, 2013

Hello everyone.

I am in process of replacing my existing furnace and A/C. Both are 23 years old. I am leaving in chicago. Below is the quote I got for 2 different models. My home total square feet is 2320 + 800 (basement). The existing furnace is using 110K BTU and its efficiency is less than 75%. Air condition is 3.5 Ton.

1) Carrier: $7300

Furnace (Performance boost series): 100K BTU. Model: 59SP5A100 (ECM motor). This is single stage.

A/C: Performance series, 3.5 ton, 42K BTU, 14.5 SEER, Model: 24ACB342

Condenser coil: Carrier CNPVP4821ALA (aluminium cased)

Carrier Humidifier and thermostat

Includes labor, installation, permit and tax

1 year labor warranty and 10 year parts warranty

I will be getting $1120 back in rebates.

2) Lennox:

Option 1: $8720

Furnace (Elite series): 90K BTU. Model: EL296V. Two stage variable speed.

A/C: Merit series, 3.5 ton, 42K BTU, 14.0 SEER, Model: 14ACX.

Cooling coil: UPFLOW CX34

Power and Bypass Humidifiers


Includes labor, installation, permit and tax

15 year labor and parts warranty. First 5 year free maintenance check up. After 5 years I need to pay 150$ for maintenance contract.

I will be getting $1120 back in rebates.

Option 2: $9070

All options are same as above except A/C will be a different model (XC14 air conditioner. This model has SEER rating 16.70 and less noise)

My questions

1) Which is better model? Carrier or Lennox
2) Am I paying correct market price or is the quote overpriced?
3) The contractors were telling that the main difference between single and 2 stage is the level of comfort you get inside home. Which is better one? Single stage or multi-stage?
4) For the furnace, Is the BTU quoted correct for my home square feet?

I am newbie trying to find some info on this topic. Please let me know your suggestion and advice that will help me in picking correct model and price. Thanks and Appreciate.

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Your current furnace is supplying about 83,000 BTU (110,000 BTU at 75% efficiency). Both furnaces you have been quoted are larger than your current furnace. I think the quoted furnaces are over sized for your house. I would think a 80,000 BTU furnace would be sufficient. The AC is probably 3 or 3.5 tons. I would recommend finding a contractor to do the load calculation to confirm the sizes. Equipment which is too big is just as bad, and sometimes worse, than equipment which is too small.

Are the prices quoted with the rebates? They seem reasonable for the equipment quoted. The first priority to find the right equipment to fit your house and needs. Don't just shop by price.

To answer your questions:

1. Carrier is considered one of the best brands. There is mixed opinions about Lennox. You are comparing a mid range Carrier model with a top of the line Lennox model. Not a fair comparison.

2. The prices are fair, they will be better for the proper sized furnace.

3. It is true 2-stage equipment is more about comfort. However there can be some small amount of energy savings when the furnace or AC can run on longer periods of time in the low stage. In my opinion I feel it is worth spending the money on a 2-stage furnace with a variable speed furnace. I feed it is a worthwhile upgrade in a location like Chicago.

4. As I stated above I feel the equipment is over sized.

    Bookmark   December 24, 2013 at 8:33AM
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Thanks Mike for taking time to answer my questions. I will get back to contractor for the load calculation.

All the prices mentioned are excluding rebates. I will be getting rebates on the top of it. Carrier contractor came forward to upgrade furnace to 2 stage model 59TP5A 96% and 16 seer air conditioner model 24 ACC6. The quote for this upgrade is $8000 (excluding rebates).

I told the carrier guys that 80k is sufficient but they want to go with 100k based on my home sq feet. I will recheck with them.

Thanks again and appreciate.

    Bookmark   December 24, 2013 at 10:06AM
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Estimating HVAC sizes based on area of the house usually results in over sized equipment. The contractor does this because he does not want to spend the time and money to do a proper load calculation. It is unfortunate but it is very common in the industry.

A thorough contractor should propose several furnace and AC models and explain the value of spending more money on additional features. I get negative feelings when a contractor does not spend the time to do this.

    Bookmark   December 24, 2013 at 10:55AM
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As usual, Mike is right on the money on this topic. I think the two stage or multi is the only option. Better comfort especially so when doing the dehu in lovely dripping Chicago in the summer.

As your system is 25 yrs old I would be surprised if it is 75% efficient. Most of the old furnaces were in the 60-65% range prior to 92 when minimum 78% was mandated. I'm absolutely with Mike on the size. Go 80kbtu, unless they can substantiate the 100.

There is another issue yu should be aware of. Google "DOE Duct Leakage" and read for a bit. Any equipment upgrade should include re-sealing/repairing your exist ductwork. Properly down that will ensure that the 80 will be more than adequate. You might check with the contractors and local code folks about this topic. It may be required. Many States are requiring it, as they should with an average duct leakage of 30%.

If I had my druthers, I'd go Carrier.

    Bookmark   December 24, 2013 at 11:26AM
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Thanks everyone. A quick update, I came to know that my current carrier furnace model 58gp125 is 125000 btu.

Sure I will do some research on duct topic mentioned.

    Bookmark   December 24, 2013 at 11:52AM
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You're spending a lot of money therefore, you want everything DONE-RIGHT! If everything is not done-right the system can lose a lot of its 'Delivered Btuh Rating' to the conditioned areas, especially in the cooling mode.

Additionally, larger homes take less Btuh per cu.ft of air or, sf of area

IMO, your existing furnace is way oversized; lowest Chicago Winter design is at O'Hare airport @ -1ðF, goes up-to +2ðF in the county.

Do a load-calc & improve areas that will lower the Btuh heat-loss as much as possible.

I am also betting that a 2.5-Ton A/C can be made to cool your home. My home uses 1-Ton to cool over 1200-sf of space; yours would be 928-sf per ton of cooling; that should be doable.

You will need the supply-Air & Return-Air duct system well sealed & get all the Return-Air filter area you can provide to increase blower airflow &U duct efficiencies.

I am willing to bet that a 60,000 Input 57000-Output N-gas furnace would handle the heat chores with a better, longer runtimes with long off-times, using a programmable-Swing adjustable on/off temp-spread room T-stat.

I've had a 95% 57,000-Output propane furnace going on the 3rd year & it has never went over 26,000-Btuh heating a 2-stoy with a deep basement 1937 1250-sf farm home.

I use -13ðF sometimes -15ðF below zero, that's supposed to be with a 15p-mph wind velocity; it only figures 30,000-Btu loss per/hour. Lacrosse WI say winter 99% design is -13ðF.

Easy way to figure actual operating performance: Keep track of burner runtime in minutes; then keep track of the first burner-ON to the next burner-ON; divide the Total time between the Burner-ON times into the Burner-Run-Time; that % times the Output Rating of your furnace.

Say the Burner (Not the Blower runtime!) runs 15-minutes, a quarter of an hour; to show How & Why it works; total minutes between Burner-ON & On-again for easy understanding is 60-minutes, one hour; 15/60 is .25% *Times 'Output' of your furnace; mine is 57000 or only 14,250-BTU/hr.

Here is a link that might be useful: Free Whole House Load-calc

    Bookmark   December 26, 2013 at 12:24PM
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You are being oversized on furnace.

No more than 80 KBTU high eff model. I prefer a 2 stage var speed model. If going single stage,then definitely a model with high eff ECM blower motor.

I would want a system that qualifies for Fed Tax Credit.

Not a fan of Lennox but correct sizing and system match according to AHRI paramount.


    Bookmark   December 27, 2013 at 10:46AM
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Thanks for detailed explanation. I checked with carrier guy and they told 2 stage 80k should fine. Mostly I will go with this model 59tpa.

    Bookmark   December 28, 2013 at 11:25AM
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"I told the carrier guys that 80k is sufficient but they want to go with 100k based on my home sq feet. I will recheck with them."

"I checked with carrier guy and they told 2 stage 80k should fine."

I am curious about the conversation you had with the contractor. Did you ask if you could use a 80K BTU furnace and installer said, sure no problem, or did you say I am not paying for a 100K BTU furnace and want the 80K size?

    Bookmark   December 28, 2013 at 2:27PM
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I asked them to do load recalculation. 96% 80k matches closely with my current model 70% (or less) 125k.

I finally installed the carrier 2 stage one yesterday.

Question: Today morning I saw some condensation (kind of ice) hanging from tip of exhaust vent PVC pipe. The outside temperate is 0F. Is this normal to have condensation near exhaust pipe vent or do i need to call installers.

Please let me know your thoughts.

    Bookmark   December 31, 2013 at 10:55AM
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I wouldn't be concerned.

What thermostat did dealer install?

It should be a true two stage model that handles the staging based on demand, not the timer on control board that will always go to high stage whether needed or not.


    Bookmark   December 31, 2013 at 11:06AM
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Exhaust gases are saturated air. It is common to have the condensate dripping off and freezing. Are you comfortable at 0* with the new furnace?

    Bookmark   December 31, 2013 at 11:06AM
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Thanks for clarifying my concern.

We feel comfortable with 0F outside. I set the thermostat to 71F. In my second floor I am getting close to 70F heat.

It is 2 stage. The first stage runs for a some time and based on demand second stage kicks on. The unit is quieter.

The thermostat model is touch-n-go carrier programmable thermostat. I didn't see any timer. It set the fan to auto and heat to 70F.

    Bookmark   December 31, 2013 at 12:43PM
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The timer is on the control board at the furnace. It is a cheap shortcut that benefits the dealer not the homeowner. I hope no less than Carrier Edge thermidistat was installed. This deserves clarification from the dealer. It is a big deal for the nice furnace you installed. If not two stage thermostat, you will be running on high stage whether needed or not. Will affect both your home's comfort as well as your pocketbook. I would want to know.


    Bookmark   December 31, 2013 at 4:38PM
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Thanks for bringing this point about thermostat. I just noticed that they installed comfort series thermostat which doesn't support 2 stage. I think it is the timer in furnace that triggers 2 stage. I am checking with dealer to install carrier edge so thermostat can control heat stages. Not sure how I missed this one. Thank again for info about this timer.

    Bookmark   December 31, 2013 at 8:17PM
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Why dealers do this is beyond me. It is downright ethically wrong. It is sneaky to unsuspecting homeowner.

Here is the recommendation from Carrier website for the 59TP5 furnace.

Recommended controls: Performance⢠Edgeî relative humidity or ComfortZoneTM II thermostats.


    Bookmark   January 1, 2014 at 5:49AM
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Update: I spoke with dealer and he is going to check about thermostats upgrade and get back to me. Hope he doesn't charge extra bucks.

One more question: I see the water drain hole next to new furnace is almost full. It might overflow any time. Is this normal or do I need to drain the water to some other way? I am concerned that if the drain gets full it will flood basement floor. Appreciate your suggestions.

Current water drain goes to ground.

    Bookmark   January 2, 2014 at 2:51PM
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Drain needs to be looked at by dealer.

And you can expect an up charge for correct two stage thermostat.


    Bookmark   January 2, 2014 at 2:58PM
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Is the drain connected to the sewer or is just a hole in the basement floor? If it is not connected to the sewer then you will need to do install a condensate pump with a drain line over to a sink or outside.

This post was edited by mike_home on Thu, Jan 2, 14 at 20:12

    Bookmark   January 2, 2014 at 4:24PM
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I think the drain is a hole in the basement. I see the water standing full and not reduced.

If I need to install condensate and pum, whom should I check with plumber or furnace guy?

    Bookmark   January 2, 2014 at 5:15PM
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The furnace installer should be able to install a condensate pump. This is standard practice when installing a 90+ efficiency furnace.

    Bookmark   January 2, 2014 at 8:11PM
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Update: The floor drain is connected to sewage pit in basement. The ejection pump was struck. I reset the pump and now the drain water is pumped out.

I will update once dealer puts the new thermostat. He is going to come next week.

Thanks guys for your suggestions. Appreciate.

    Bookmark   January 4, 2014 at 9:59AM
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