Cindy, I did not make that statement. My own (non-PRO) opinion is that the decision should be based on several factors, as well as your personal concept of comfort.

Most importantly, the unit should be sized according to the 'calculated' heat gain of the property as well as the indoor (your thermostat setting) and outdoor 'design temperature' of the area. Philly's design temp is 90 degrees. This also applies to furnaces (OD design temp is 14 degrees). Your heat gain is composed of 2 parts; sensible, which has to do with temperature you can feel; and latent, which refers to humidity. Your unit needs to be sized to cover the sensible portion, as it is much higher than the latent. By the way, most contractors don't/won't do it.

Yes, I know it's been a lot hotter than that, but statistically, the temp is at or above design about 2-3% of the time. If you size according to the 100+ temps, your unit will be oversized about 98% of the time, resulting in short cycles (bad for equipment) and a cold, muggy house.

Units with more than 1 stage deliver more comfort (longer run times with less capacity), rather than efficiency. Whether or not to choose one goes back to my earlier comments on sizing. Many contractors will push a 2 stage unit, stating that it will run mostly in low stage. Insist on a heat calc.

If you like to set back your thermostat, a heat pump probably isn't for you as your backup heat may be called into play, thus losing any gains in heating efficiency. Also, the air coming out the vents is not as hot as with a gas furnace. You also need to decide whether to stay with gas as backup, versus electric. Your contractor should show you calculated savings based on your utility rates.

If you go with a 2 stage furnace, make sure it is a true 2 stage, that is, one that can be controlled by a 2 stage thermostat (insist on one) as opposed to one controlled by a timer.

Probably more info than you were looking for. Hope it is useful.

V

You can't have a 1-stage furnace work with a 2-stage heat pump. The furnace must have a variable speed blower.

A 95% AFUE furnace will run more economically most of the time than a heat pump with today's prices of natural gas. Natural gas prices would have to increase 20-25% before the heat pump would be consistently cheaper at all outdoor operating temperatures. It would be better use of the money to put it towards a 2-stage AC than purchase a 1-stage heat pump. But unfortunately the NJ Clean Energy Program policy does not recognize this.

I am sure gas prices will increase at some point in the future. However hydraulic fracturing (aka fracking) has really changed the landscape of mining natural gas. The mining of Marcellus Shale in Pennsylvania is helping to supply a large amount of gas to the Northeast part of the US. New York state has finally approved gas mining in some counties along the PA border. This will probably expand once the land owners realize the money making potential of gas exploration. If the mining can be done without harm to the environment then we should have low gas prices for the forseeable future.

mike and vees.....and NycRavi

I did do some more reading and see that I would indeed need the 2-stage furnace with a heat pump because the single stage doesn't come with variable speed, but rather with multi--which I read is NOT the same...

I think Mike has a point that the 2-stage ac might be better money spent than on hp, because I will be getting the 95+ furnace anyway (my old one is 90 which makes it a little easier)

I am hoping they can get that combo (a/c and furnace) to come in at percentage for the rebates, but if not then the hp will probably come out cheaper for me due to rebate.

Vees...This is where I got confused when your wrote "Last year, my 4 ton 2 stage unit ran about a minute in 2nd stage (first time in 3 years). Recently, with a 100+ degree day, it ran in second for a few hours. "

I think I had it backwards because if I had ONE stage it would be HIGH wouldn't it? I was thinking it would be in LOW and you had said it barely ran on high, so I mistakenly was thinking I only needed one state. I guess 2 would make sense to get the lower run cost of low stage..(It IS cheaper to run on LOW correct?? Maybe I have that wrong too)But maybe the extra cost of the 2-stage offsets the low stage savings....but then (can keep thinking it over toooo much) they claim the 2-stage is more comfy. My a/c does make me too cold sometimes downstairs while it is nice upstairs, maybe 2 stage would help that?

Mike, I had thought HP was overkill with 2stage High eff furnace but a lot of people suggested it. Some people love it. I have a feeling either one would be good. Does a 2-stage ac handle the humidity well (NOT infinity)??

I believe the Manual J put me at 3.5 tons, but I don't know if Carrier comes in that, they have told me 4 ton is what I need and I have received quote of 80,000btu for furnace.My house is 2850 with southern exposure on the front. It really heats up the front in summer and some in winter, but the family room is on slab, in the back, so it stays chilly in winter.

NYcRavi, what did you decide to do as far as stages etc? Did you find much price difference between one and 2 stage? Did you get in under 8k after rebates?

Too many choices!

If your manual j requires 3.5 T, you are stuck with a single stage, as 2's only come in whole ton sizes. A single stage unit runs at whatever capacity the unit has, e.g., a 3.5T unit runs at 3.5 tons. During mild spring weather, it may run at very short intervals.

Regarding my statement on my unit: I was 'upsold' (misled)into the 4 ton unit. As a result, it only ran in low stage, but switched to high for a minute or so. for all I know, we could have been doing some serious cooking. During the last bad heat spell, it ran continuously on high for hours.

A 2 stage unit running in low stage is not (somewhat, if any)more efficient than a single stage unit of the same SEER/EER. Multiple stages (long run time at lower input) are for comfort. It takes X number of BTUs to cool your house. You can supply them quickly (short period of high electric consumption) or slowly (long period of low consumption). We just got our electric bill today, and were quite pleasantly surprised. We paid a lot more with our old 4 ton single stage unit.

BTW, you are looking at what is known as 'hybrid heat'. When your HP has reached its limit, it will shut off and the furnace will take over.

V

The purpose of a 2-stage AC is increase comfort. It does not decrease operationg costs. Any 2-stage AC will help lower humidity levels.

I would be curious as to who is recommending getting a heat pump in addition to a 95% AFUE variable speed furnace. It is overkill in my opinion.

Single stage Carrier ACs come in 3.5 ton sizes. A 2-stage unit would need to be 4 tons. I would not be concerned about going to a 4 ton 2-stage AC if the manual J calculation was 3.5 tons. I have this situation in my house and it works great.

Sorry, I hijacked this thread......

Mike, The heat pump lets me get the rebates and the ac apparently doesn't because my savings isn't great enough with just ac (I had old 90, other people moving from an 80 could probably skip hybrid) I don't think there are many good options to replacing the furnace except for going to 95... Would be silly to go down. Would there be much cost savings going with a 93 vs 95? I think that is why they are selling me on it, plus Since July 15 it has to be 95 for the program. Guess I should have noticed that sooner back when 92 was eligible. Hopefully the "energy star" certification I get will help me sell my house some day (selling point only to those who concerned about the utility bills...some people aren't)

I go back and forth....could spend less, but the increased comfort intrigues me as does saving energy, by the air sealing and insulation, which I'd never do if the rebate didn't force me. The rebate basically is paying for that and the water heater. I am trying to pay for everything what others pay for a decent hvac alone. The energy savings (claimed) is why I consider the heat pump and furnace. I should have the cheapest heating bill on the block!! (if any of the claims are true) would 11k be in the ballpark for carrier hp, 2 stage furnace and the other stuff I've previously mentioned? Don't know if the heat pump is one or 2 stage. I asked for model numbers but don't have yet.

As V stated, staging is more for comfort, not 'sufficiency'.

For both AC and heat, the theory is that at some times of the year (shoulder seasons) you do not need all the cooling/heating available from your HVAC system. So being able to operate it at a lower 'stage' is a good thing. But as he said, it becomes high cost / short time or lower cost / longer time. It may save some, but the equipment itself costs more.

With a 2-stage gas furnace with HP, the HP starts supplying heat first. As the temperature goes down, the HP becomes less powerful. Eventually the 1-st stage furnace comes on. As it gets even colder, the 2nd stage comes on.

Hyjacking a thread is considered inappropriate and bad forum etiquette...

IMO

veesubotee - I didn't make it to Jackson outlets as yet (busy with house) My wife however says there is some good deals there
I will definitely review his temperature inputs.

Cindy - My initial plan was to utilize that program but most of the contractors seem to inflate their prices where the 5k rebate benefits them and I'm stuck with a 10k loan. I will be spending almost the same amount

Cindy - I found the difference to be about $500 dollars. Hard to really tell, contractors keep moving the type and size of equipment to really figure out the difference.

Vestuboee- Thanks for the explanation, I believe I would be in that same position because my home calls for a little less than 3.5 tons AC as well. I believe if we decide to go 2 stage, it will have to be undersized at 3 ton and I will have to do some serious insulation as 4 ton 2 stage might be over sized.

Thread officially hijacked :)

I'm still awaiting the written heat calculation before moving further.

Thanks all

NYC, let me know how it turns out....I am trying to decide soon because I am tired of trying to figure out the best angle. I figure that I will be spending about 9-10k for good hvc alone anyway, so I may as well do the program. I think I will have to spend 10-12000 (after rebate) so I will have some small rebate benefit which I figure goes toward the sealing and hot water,and also includes insulation, but due to the price inflation (which we are not the only ones who noticed) I think I will realize about half of the rebate...but the 0% loan is nice...and I'll get the air sealing done which I do believe will help the system work better. Without the program I would not have it done..

I am also strongly considering the Amana. My best Amana quote is for a good system, probably like a low level Infinity (both 2 stage w/ communicating therm) and it is 2k less in price than Carrier. I have Amana down to about 11k after the rebate. If I can get it to 10k I might do it, or try to get Carrier down to 11k, but it will be Infinity furnace and control and a lower level performance HP. Not sure if the quoted HP is a good move. Might consider 12k (current quote) with a 2 stage HP if I can negotiate that.

I'll add a little something concerning the ManualJ temperatures.

Around here (DC), the so-called 'average' summer temperature is 89F. The weatherman stated that in 2010 the area had 50+ days over 90F. In 2011, over 40 days. This year it has been over 35 so far with some weeks of over 100f. Using 89F as the highest designed temperature would have resulted in some 'warm' houses.

Also, you have to watch that the person doing the calculation does not use the Energy Star temperature of 78F indoors for summer, unless that is what you desire. Imagine how warm you would have been if your system was designed to max out at 89F with an indoor temp of 78F when it was 105F like it was a few weeks ago.

And before someone yells at me about being oversized, all I'm suggesting is to be more realistic about the design temperatures for your system.

I hope I will remember what you said about the calcs. 78 would not do it for me, though with lower humidity (as hoped for by the 2 stages and/or variable blower.....it might not be as bad. Today when it was 75 on my therm it was time to turn it back down to 72 or 73.

I thought they were all,designed to cool by up to 20degrees? Though it is true when it's hitting the high 90's that hasn't been enough and mine has struggled to get to 75 or 76....

Any other input regarding the average temperature utilized for Load Calculation?

Tiger?

Vestubee?

Mike?

I always hear, bigger isn't always better but I surely don't want an inadequate heating and cooling system.

Imagine explaining to my wife why the house is still warm in the summer after spending all her money she saved for a new kitchen.

Is it just me or I see a global warming trend :)

I totally agree with Weed.

Man J is only good when correct information is inputted and that includes design temps for both heating and cooling both inside and outside.

A homeowner and a dealer have to be realistic especially on design temps. Averages are fine on paper but make certain real world conditions are taken into consideration for one's location and climate.

89 degrees for Washington, DC is absurd. I might even question whether 95 degrees is adequate. And then there is the inside thermostat setting that can vary depending on what s comfortable for the individual homeowner and his/her family.

Many experts say to size to the average both heating and cooling. I say that can get you into trouble. I know I have excess capacity in cooling but my home handled the 100+ degrees we had in the South for about two weeks just fine. Can't say that for my neighbors and friends who complained. nothing is wrong with a fudge factor if reasonable. You just don't want to go overboard and create short cycling issues and/or inside humidity problems. Commonsense goes a long way even in HVAC.

Man J is a great tool but use it as a guide. Just like life, nothing is just black and white.

IMO

Also consider if you like to you have gatherings in your house during the summer. Having an extra 10 people in the house while cooking, eating, and drinking can really overwhelem the AC.

Good point if you entertain alot. If you don't, then schedule those type gatherings when winter and summer weather is closer to the average and moderate compared to extremes.

IMO

Will definitely take all the advise into consideration when the contractor returns from vacation. Load calc will be completed early next week. Will update accordingly

Thanks everyone

After(if/when) new equipment is installed, please post back and let everyone know the details. Hope everything works out.

V

More questions

As previously stated I�ve decided to choose a 2 stage furnace and a two stage condenser with combined input for you folks and countless hours of research. Unsure if the savings for a two stage condenser is worth the $1300 more in upfront cost....

American Standard: OPTION 1
1. 95% furnace 120k 2 Stage gas -Variable speed � AUH2C120A9V4 � XV-95
2. High Efficiency single stage 4 Ton Condenser � 4A7A5049 � ALLEGIANCE 15
3. Matching coil 16 Seer/13 EER AHRI # 3938933 � AMERICAN STANDARD COIL
4. Thermostat � CONT800
* qualifies for heat/cool advantage and save green--- TOTAL REBATE $1800

American Standard: OPTION 2
1. 95% furnace 100k 2 Stage gas -Variable speed � AUH2C100A9V4 - XV-95
2. 2 stage 4 Ton Condenser � 4A7A6048 � ALLEGIANCE 16
3. Matching coil 16 Seer/12 EER AHRI # 5181858 � AMERICAN STANDARD COIL
4. Thermostat � Cont800 series compatible 2 stage stat
*does not qualify for the NJ cool advantage but qualifies for heat advantage/save green--- TOTAL REBATE: $1300

Please look past the size of equipment, still awaiting the written load calculation before deciding on the size. a modest price increase/decrease.

OPTION 2 will cost approximately $1300 more than OPTION 1.

QUESTION:
1. Is it worth spending $1300 to go from a single stage condenser to a 2 stage?
2. Comfort gain or loss with either choice? Comfort is more important than spending a few extra dollars on electric bill
3. Heard Lowes now sell (sub-contract) Trane equipment (is it worth involving another party�had 5 contractor proposals already?

Thanks All

NYcRavi

Hi again!

Maybe with a different coil they can get you the rebates on that 2-stage? The a/c i am getting is 2-stage (Carrier). On their website they list it as "up to 18 seer and 13.8 eer." With the coil that is being used I am getting 16.2 seer and 13.0 eer, which I think meets the rebae standards of 16 and 13 that you need. I don't know if there are different coil options because when I tried the ahridirectory.org I didn't find too many options. You might try it and see. It worked best for me to put only the first few digits of the ac and even less of the furnace. I also had the cert reference # so I could pull up my exact match that is being used.Also, check your mfg website to see what the advertised Seer potential is so you have a better idea what to expect. Ask contractor why you can't meet that (if it says it is over 16 and 13).

I don't know if the extra $ is worth it here in NJ. I think many people are satisfied without it. I was going to get 1-stage but i didn't like the 1-stage he originally offered so then he bumped it to 2-stage for the same price. I'm not getting any bells and whistles, but I'm confident that being a reputable brand and dealer that I will be fine. I know my system will be better than many of my neighbors who are only interested in the cheapest.

I like the concept of POSSIBLY saving $ by running in 1st stage, though my understanding is that the longer run times will eat some of the savings. As long as it is not mre expensive to run, gives me more comfort, and has that possibility of using less electric I will be happy.

Check your coil model, see if there is an alternative that can get you the rebate and lower your cost. I told contractor that I decided I only wanted to spend "X" and that I wanted a better option than what he presented. I told him I was willing to commit that day if he could meet my proposal. This may not work if your guy isn't overpriced. I knew mine probably had room given the exhaustive (!) research and that they are a large company. Let someone else pay for their advertising!

Good luck! I am excited to get mine early Sept. I hope we get a little heat wave to test out the a/c.

The 2-stage AC works well on reducing the humidity on those rainy days when the temperature is in the low 80s. You have to make a decision as to whether you want to spend an extra $1300 to be more comfortable during days of high humidity.

I recommend you not get a third party coil in order to ahieve an 13 EER rating. The rating may change when you match it to the correctly sized furnace.

You are better off avoiding Lowes and working directly with a good HVAC contractor.

The furnace in option #1 is definitely oversized.

You definitely want a true two stage thermostat like HW VP IAQ, not the 800 series you are being quoted.

The sgl stage condenser is fine especially with DOD feature of the HW VP IAQ stat.

I would not purchase HVAC through a third party big box store.

I would insist that a written, properly performed load calc is part of any deal.

IMO

This is just my verbal load calculation, written will come at a cost of $400 or after agreeing and signing the proposal.

The heat load calculation results:

Design Conditions
INDOOR: - OUTDOOR:
Summer temp set at 75 - 95
Winter temp set at 74 - 05

Summer Grains of Moisture 96

Daily Temperature rage: High
Total Cooling load needed 37,672 BTUH = 3 tons
Total Heating loss needed 90,972 BTUH= 100,000 BTU
Total square footage with basement = 3328.3 sq. ft.

I am still thinking the:

-XV-95 variable 2 stage furnace(100,000Btus)
-Single stage condenser (3.5 tons)

Tigerdunes:
Does the Azone950 stat come with the DOD feature?

Per your post: "This is just my verbal load calculation, written will come at a cost of $400 or after agreeing and signing the proposal.

The heat load calculation results:

Design Conditions
INDOOR: - OUTDOOR:
Summer temp set at 75 - 95
Winter temp set at 74 - 05 "

Per my post: "The outdoor design temps for Long Branch are 90/13 (summer/winter). Mine are 1 degree more extreme (Philly) in summer; less in winter. Don't let them 'adjust' them. Also, be sure that they use your 'actual' indoor temps." I chose Long Branch as it is the nearest listed location.

Looks like he's building in a bit of a fudge factor. Are the indoor temps (75/74) accurate?

V

tigerdunes---is the DOD feature available with the azone950?

Veesubotee---I don't quite understand the difference in the temperatures? what would happen if he fudge the numbers from from lets say your outdoors of 90 to his temperature of 95. Please explain.

I want to decide on this before the end of the week. What should I say to the contractor about his load calc and how to modify?

Thank You

By using a higher outdoor design temperature, he is saying that the home requires more BTUs of cooling (oversized) than what would be required using an accepted design temperature. Result: shorter run time, less humidity removal. Not good.

Likewise, using a colder DT for wintertime states that the heating loss is greater. Result: shorter run time if fudging results in a larger unit, possible greater temperature swings, less comfort. Did I mention higher operating costs?

Do you actually set your thermostat at 74/75 as stated, or are those numbers 'adjusted' also?

Many contractors will add 'fudge' factors.

V

Yes that's our ideal DT temperature (young children).

Ideally I would want to have the perfect sized equipment for the house, however I would definitely prefer over sized over undersized.

Total Cooling load needed 37,672 BTUH = 3 tons
--I believe I would go for a 3 ton even if the load was 30,000 BTUs

Total Heating loss needed 90,972 BTUH= 100,000 BTU
--I may be ok with an 80,000 BTU furnace, however I could be in some trouble during a cold spell. So going with a 100k Btu would be safe since I'm choosing a 2 stage variable furnace.

This is just my opinion and I'm no professional hence the reason for seeking assistance.

You should go for 3 1/2 ton AC and 80 KBTU 2 stg var speed 95+% eff furnace with a 4 ton rated blower.

Of course you will need a true two stg thermostat where it controls the heat stages and not a timer on the furnace control board. The HW VP IAQ not only is a true two stage thermostat but also has DOD feature for great dehumidification.

Add a whole house airvfilter cabinet.

IMO

I agree with everything you say tigerdunes. Thanks for returning, was afraid you you wouldn't return.

I really want the 950 thermostat because of the ability to control while away from home. I travel a lot for work. According to the contractor. 950 doesn't come with the DOD feature but has the ability to adjust blower settings lower to increase dehumidification. Is that comparable with the DOD feature?

Please answer ASAP. Contractor is working on my final proposal.

Thank you

tigerdunes weekend is over, please come back... your opinion is valued

I think the 950 should be fine.

However verify with dealer that it has following:

1.dehumidify on demand feature
2.true control of the furnace stages high and low, not the timer on control board

If it does not have these features, then request the latest HW VP IAQ Prestige with wireless remote capability.

IMO

Mike said, "The purpose of a 2-stage AC is increase comfort. It does not decrease operationg costs. Any 2-stage AC will help lower humidity levels."

Mike, would you agree to amend your statement to point out that with the possible lower humidity levels associated with a 2-stage AC/HP that it may well be as comfortable at a higher set temperature than with a single stage unit?

This in fact will result in a lower operating cost.

Yes I agree lowering the humidity level may allow up to raise the temperature level a degree or two and result in a savings. This is what I do in my house. I typically have the thermostat set to 78-79 with a 40-45% humidity level which I find comfortable, but others may not.

The savings are small however and may never offset the additional cost of upgrading to a 2-stage AC.

Is there any data to support lower electricity use by simultaneously lowering humidity and raising temp? Lowering temperature and lowering humidity both require energy.

If we change the thermostat setting from, say, 75 degrees to, say, 77 degrees holding outside temp constant, does it not follow that less BTUs per unit time will be required to MAINTAIN the higher temperature?

"If we change the thermostat setting from, say, 75 degrees to, say, 77 degrees holding outside temp constant, does it not follow that less BTUs per unit time will be required to MAINTAIN the higher temperature?

I don't think that follows unless the absolute humidity is held constant. If you need to reduce the moisture in the air further to be comfortable at higher temp, that represents an additional load on the HVAC system. I don't know how the numbers will fall out.

The lower humidity results from running the AC at a low stage for longer periods of time. The long cycles allow the air to dry out without lowering the temperature. It does take less energy to keep the indoor temperature two degrees higher. However the efficiency of the AC in the low stage may not be as good as the high stage. I never see efficiency ratings for low and high stages. I also think leaky duct work has a bigger impact on efficiency of the HVAC system running on the low stage versus the high stage.

If you have a cool to dehumidify feature on the thermostat, then lowering the humidity may increase your costs. You would have to turn off the feature if the goal is to try to save money.

Mike said, "If you have a cool to dehumidify feature on the thermostat, then lowering the humidity may increase your costs."

Absolutely correct AT THAT THERMOSTAT SET TEMPERATURE.

The point is that by expending that energy to reduce the humidity (and simultaneously contributing to the cooling of the indoor air) you will feel more comfortable than with the higher humidity and allow you to increase the set temperature which will reduce the cooling load at that new higher set temperature.

I always assumed the low stage was MORE efficient. I guess it would depend on how long each stage runs to achieve the same temp. I never really thought I had a humidity problem inside so I got the 2-stage thinking it would be cheaper to run. I am thinking about the days when it is in the 80's, that it would run in low because I am only trying to cool it to about 74. I assumed it would be cheaper to run it in low on those days even if it takes a little bit longer to get the temp down, than running on high to lower the temp quickly.

I think many people don't have a good understanding of 1-2 stage, especially for a/c, yet so many people claim it is better. I hope it is because I went for it. Is it a calculation of how much energy it uses per hour times how many hours it runs? It it costs $5 hour to run in first and runs 2 hours/day it would be $10 and if it costs $7.50 to run in high but only runs 1 hour, then second is cheaper? But if it runs 4 hours in first=$20 and 3 hours in second= $22.50 (to achieve same results) then first stage was cheaper. I assume if one knew all the costs and run times to get from temp A to temp B that you could figure out if/when it is cheaper to run in first or second stage.

THEN add in whether you can keep the temp higher if you get the humidity lower...and it gets more complicated.

I'm sitting here thinking I should have just ordered the one-stage...but hey, it's only $$! (and the markup between the two made me think the 2-stage MUST be better!)

Wow. Look what I started. :)

"Wow. Look what I started. :)"

No, just a poster that has read a couple of posts and not researched the issue. :)

Thanks Cindy, I have to decide today whether to go within single or two stage. You all were instrumental in my decision to stick with single stage condenser.

Only issue now is wether to err on the side of caution and go with the 3.5 ton and not get the 500 dollar rebate, or go with the 3 ton according to my load calc (37xxx)And get the rebate.

My current 3ton Lennox value series cools my house sufficiently except for the two larger rooms. Hopefully the variable speed motor on the 2 stage furnace and coil (xv 95) will assist with spreading the cool air around.

Hold on RAVI! I am not sure if I understand it correctly. I posted what I THINK is how it works, but the guys on here may tell you I am wrong. I posted to see if I understood it correctly or not, but got what I think was a veiled insult from saltidawg, not sure if he intended that or not....

I ended up with the 2 stage, but I think it was knee jerk reaction to a price reduction my contractor offered me that made it seem like a good idea. I so excited that I got him to lower his price that I forgot the big picture and didn't ask him if he could also give me a better price on a one-stage (the 1-stage he had offered was a lower end, so I would have had to negotiate a better 1-stage). Therefore, I think I may be spending more than I need to and am HOPING the 2-stage was a wise idea.

If price is the issue, get the 1-stage. Are you the guy where it was $1300 more? My quote from a large company here, was $1300 more for the 2-stage than the 1-stage. It ended up as a decent price for a package of work I was having done so I went with it. If I were just doing the hvac, I would not pay $1300 more for the 2-stage, with everything else the same. I think mike_home has some very good posts explaining everything. If you can afford it I think the 2-stage is nice to have, but not necessary.

I have also read and been told that the 2-stage will help with the uneven cooling because it blows lower but longer. You might see if anyone responds to that claim, though I see you say they are larger rooms...can they add vents?

Also, this may not be true, but my the salesman (claims he was a mechanic/installer) said that my furnace needs are between 80 and 100k so he is giving me the 100k because the blower will be stronger (they will and that should help with the cooling upstairs. I have 2 rooms that are usually warmer, they get the south sun that doesn't help either.That is sort of what you are saying with the cooling and the fan.

Why does the 3.5 not get the rebate?

In a Carrier White Paper eight years ago looking at the differences between three candidate compressor configurations, 1) Scroll, 2) Standard Rotary Twin-Screw, and 3) High Efficiency Rotary Twin-Screw, the following is provided for the Scroll:

Full Load EER in BTU/Hr-Watt 9.6 - 9.9
Part Load IPLV in BTU/Hr-Watt 13.5 - 14.0

During part load operation the Chiller Efficiencies for a Scroll Compressor much higher. Notice that the units are BTUs per Watt-Hour.

During calls for humidity reduction OR simply to maintain temperature by operating the compressor at reduced load, there are MANY more BTUs of heat extracted from the house PER Watt-Hour than at full load.

IF the A/C system can keep up with the interior temperature set point, it is always cheaper to extract the BTUs with the compressor at reduced load.

I fully understand that cheaper is not always better - come back from vacation and the house feels like an oven. You don't want to spend days cooling down.

Outside temp goes to 110 degrees... you can't keep up with controlling inside temp with reduced load.

I meant no disrespect to anyone. I also don't make any recommendation to the OP, that better comes from the many knowledgeable installers and technicians. I did want to clarify something about costs, however.

Yes it would cost $1300 more if I was to go with a two stage condenser. I have a single stage currently and it sufficient. I cannot justify the long term savings and comfort.

I'm hoping the variable speed blower (4ton) condenser(3 ton ) would assist in cooling the larger rooms better. Adding larger vents are possible if this doesn't help. I don't want to do that now if there is a chance I may not need it.

No more room to fudge the load calc (37xxx.). They have to round down to 36000 (3 ton)

As per furnace. 80,000kbtu without basement (man cave) 100,000 kbtu with basement. I do have a fireplace in the basement however. So I'm still on the fence with the furnace size. I have till end of day to make a decision, just tired of researching already.

Thanks for your lengthy input everyone

"cooling the larger rooms better" is strictly an airflow (vent) problem. The VS blower won't help with this. But it has other virtues (better humidity extraction).

The outdoor design temperatures used in the load calcualtions seem more pessimistic than I would expect for Jackson, NJ. Therefore you should be fine with a 3 ton AC and 80K BTU furnace.

NYcRavi,

I was curious whether you got prices on single stage furnace or 80% furnace and how those compared to 95%+ w/two stage. I'm trying to justify the price I am paying for my 2 stage a/c and high eff furnace by comparing it to what my neighbor paid for an "up to" 18 SEER single stage ac and 80% two stage furnace. Based on your estimate of $1300 (and mine) I would expect the 2 stage to be at least 500 more (because my quote for a single stage was not as high eff as my neighbor got) and maybe another 500-1000 for high eff furn over 80%? My decision is made and contracts signed, but when people ask what I paid (because sometimes it comes up) and I tell them they seem to think I overpaid. I like to feel good about my decisions and not second guess myself, so I think I am looking for someone to tell me that I am not necessarily overpaying for the upgrades.

Of course, this neighbor thinks it made sense not to upgrade to 95% because the contractor told her that her vents go up outside uninsulated walls. I doubt that is correct. My house is the same builder (dif model) and mine don't. She didn't grasp that either way the heat she is losing due to her vents is still costing her more to generate. She is just losing more expensive heat, MORE reason to upgrade! I didn't use that contractor!

I didn't bother with single stage or 80% efficiency equipment, can't comment....
approximately 8k for
Xv-95
American standard Allegiance 15
4 Ton AS coil
Minor mods on ducts
17 gal humidifier by-pass
Accuclean electronic filter
Honeywell prestige 2.0 iaq stat

Everyone,

I finally got my Heating & Cooling system replaced

American Standard:
3.5 ton Allegiance 15 Single stage Condenser
100kbtu 95% 2 stage furnace w/variable fan
17 Gal bypass humidifier
accuclean electronic filter
HW Prestige 2.0 IAQ stat.

(Bradford White 50 gal high efficiency hot water heater)

only a few days... still experimenting... so far i'm pleased... nice and neat installation.

Thanks everyone, your input made a tremendous difference as I did not know anything about HVAC....