Two or variable speed is all about comfort, not efficiency. Efficiency gains with those systems will never recover the added cost. Humidity control should be much better. I'd want it in your climate. With lower humidity, comfort is often better at significantly higher set temps. This is also better for the structure because condensation is minimized. The dew point where I live is 75 right now. By the time I get home shortly, the RH in the leaky home will be in the mid to low 40s. Temps in the mid 70s and I will be very happy with it. That is what variable speed can give you. The ECM motors in my systems also run very easily with a relatively small backup genset because there is no start up surge.

Thank you! Do you think there is a large difference between 2-speed and variable to justify the higher price tag? There are mid level one speed as well. So many choices.

It is difficult to answer that question without the model and pricing information. As you move up in models you usually get more than one feature added for your additional money. Sometimes the price difference is small when you factor in all the manufacturer and utility rebates. It is a lot of data to analyze.

Does the have have natural gas? If it does, then you should consider getting a furnace instead of a heat pump.

2 stage and variable speed condensers are all about comfort, not savings...you can not justify the upgrade price over a single stage 15-16 SEER AC condenser with a reasonable payback...it just won't happen!

IMO

However, you should be looking at a variable speed BLOWER. This will help humidity removal over a single fixed speed blower.

There can be a small savings if the thermostat setting can be raised a degree or two because the humidity is lowered from 50% to 40%. It is difficult to estimate how much that savings would be. I can just tell you from my house that 76 degrees at 40% humidity feels uncomfortably cold to me. The OP sets the thermostat to 70 degrees at night so I am not sure how this would affect savings. I would have to sleep with my winter coat if I did that in my house.

Air handlers connected to 2-stage condensers can be either multi speed or variable speed. Multi speed means there are two or more fixed speed taps that are set at the time of installation. A variable speed motor is a usually DC powered that can run a large range of speeds. In a communicating system the speed will change depending on what the thermostat is telling it to do. For Carrier is may be monitoring the static pressure and ramp up the speed in order to push the desired air flow. The DC motors are much more expensive than the multi speed type.

The Trane or American Standard heat pump with the 15-16 SEER rating is probably the best value. Then get a price on the 2-stage condenser if you want to get better comfort. The 2-stage condensers only come in whole ton sizes. So it may mean a 3.5 ton single stage vs. a 4 ton 2-stage. This also adds to the price differential.

The Carrier heat pump may also be an option for South Carolina if there are fewer defrost cycles. I will let the heat pump experts weigh in their opinion on that. The AHRI numbers will give an idea on heating and cooling costs for the various brands and models.

agree with weed plus I would want a thermostat that has independent dehumidify on demand feature...especially considering OP's location and climate!

IMO

Thank you everyone! No natural gas. Has to be a heat pump so we have heat. Old heat pump heats fine EXCEPT during our few cold snaps (5-10/yr) where its well under 30 for hours.

mike_home, what is DC powered? Communicates? Thermostat tells it what to do? Thermostat is downstairs, where its cooler, will upstairs suffer?

LOL on wearing the coat, other family members and visitors actually do. I like/need it cold, I like the cold hitting me, its so miserably hot here.... and don't sleep well unless its under 70. I have even wondered if the lower speed of a 2-stage (and maybe the lower speed of a variable handler) would underwhelm me... If I can run HP at temps I wish, humidity in the house is mid 50s, but yesterday with over 100 outside, humidity inside was 60% and it was 76 in here, and it was warm. Again, this is solved putting thermostat down where I like it at about 72 during day, but my older unit isn't up to that anymore. It cuts out.

I am a bit in undecided land.. but leaning heavily toward mid range single speed. I can be convinced otherwise though if the price isn't too high and its a great benefit, not marginal. I am wondering if getting a higher SEER (16ish) single speed might work as well as a 2-stage model. I *think* higher SEER single stage and lower 2-stage are somewhat near each other in price. And several mentioned "defrost on demand" which could rule out Carrier.

It seems the consensus here is to get a variable speed air handler? How does that work with single speed compressor and with that limit, is the extra cost justified? I also lean toward "uncomplicated" systems so maintenance costs are not too high. Speaking of complicated, is defrost on demand automatic? Who sets that up? When I narrow down, I'll ask you all for proper thermostats for short list.

Prices: 3.5 ton, 4 on 2-stage/VS: Carrier: Infinity 18VS ($11,700), a 5-stage he said no one gets, and Performance 16 2-stage ($9100). He was so opposed to single speed he didn't quote one. The Trane quotes were XR14 w/tam4 ($5900), XR15 single speed w/variable speed handler ($8400), XR17 2-stage ($9900 this one doesn't have much better efficiency than XR15), XV18 variable speed ($12,000). We have pretty much decided most expensive option in both are off the table.

I have seen bad reviews of the XR14 (but one liked it w/tem6 handler), better on XR13 (can handler be upgraded?), so I can get a quote, but noticed lower cooling numbers on that...Other models I have found with positive reviews are Tranes: XR16 (energy ratings very slightly higher than XR15), and XL__i's: 15, 16, 18. I think the XL18i is close in specs to the XR17? The XL15i has good energy numbers, but only slightly higher than XR15, but I don't have a quote, I'm trying narrow down before I ask for more quotes.

I am getting chills thinking about sleeping in a bedroom with thermostat set at 70. But if that is what makes you comfortable then go for it.

Single speed motors are AC powered. It is either 120v or 240v. A variable speed motor is more efficient if it DC powered. So built into the air handler is a AC to DC converter. This is part of the reason why variable speed equipment is more expensive.

A communicating thermostat like the one quoted with the Infinity system tells the air handler to slow down the air speed and operate at the low stage in times of high humidity. This feature is sometimes called dehumdify on demand. The thermostat may run the AC longer in order to reduce the humidity level even if the temperature in the room is already at the set point.

Connecting a variable speed air handler with a single stage condenser has some value, but not a lot in my opinion. The air handler speed can slow down to help dehumidify, but it can't go too low or the coil will freeze. If you are going to spend the money on a variable speed air handler, then it makes sense to spend the extra money on a 2-stage condenser.

Two story house usually have temperature differences between the upper and lower floors. That is a duct issue and not a thermostat issue.

The humidity level should be below 50% in the summer. If you are going above 60% then that is a problem. Not only is it uncomfortable, but you have the potential of mold growth.

The Carrier Performance equipment is good value. I suggest getting quotes on those air handlers and heat pumps. Get quotes on the equivalent Trane equipment. Be aware the Brant is the same as Carrier, and American Standard is the same as Trane. You may do a little bit better on pricing with those brands.

Whatever you do don't go with the cheapest contractor based solely on price. You want a proper installation which is typically not cheap.

Thanks!
HA about 70... Cold ears and nose, we've gone too far..

I did get a quote for Carrier Performance 16 ($9100). So you are saying single stage all the way, or 2-stage/variable all the way, no hybrid, right? What about Trane XR15 great energy numbers, its one-stage with variable handler? I guess I could do XR15 w/single speed handler as a mid range option? I'll do energy credits/rebates only if its to my benefit, we get $500 - $700 back from fed and utility combined, so its not a huge amount. If it bumps me up to a better system, great, but so far, the bump is thousands, not hundreds. Trane quote was for XR17 ($10,000), but that unit's energy numbers aren't that different from XR15. Do you think Perf. 16 and XR17 are comparable?

Both installers are reputable, and not single owner type, companies with good support, because it is very necessary here if air goes out... each is authorized dealer.

I'm wondering about all the electronics/software/etc. we have thunderstorms regularly with strikes right here, we've been hit once. I wouldn't want fried expensive boards etc. and also need the ability to quickly hit up temp button when a strike is close.

How do XR15/XR16/XL16i compare in your opinion?

I wouldnt pay the $1500 difference between the XR15 and XR17 as quoted. You'll never make that money back in energy savings.

IIRC, the differences between the XR_ and the XR_i is the proprietary top and longer warranty. But I could be wrong about that.

For weed, you mean XLi...but you are correct, the XR and XLi insides are basically the same...

I have Carrier Infinity 2-stage AC condensers with variable speed furnaces. They do a great job in controlling humidity. That would be my choice.

The Carrier quotes seem to be high. I would have thought the prices in SC would be better. Any other Carrier dealers in the area? If not then the Trane may be the way to go.

weedmeister, no, even if its the jump between single and 2-stage? I don't want to pay $10,000 anyway... and you are right, energy numbers are not that improved.

tigerdunes, I have been scouring old threads here and another forum, here is what is said about XL, cover helps protect unit from leaves and ice (not a huge concern, 2-3 times in 18 years we have gotten a dusting of snow), and there are less parts in the outdoor unit, and TVX (whatever that is).

Won't I get better humidity control (not a huge issue except for raising temp right now to not finish off the unit) with a 15-16 SEER single stage (now we have 10)?

Still leaning towards a "better" middle range 15-16, maybe 17 SEER less complicated single speed. XR15 keeps coming up everywhere I go... anyone know how much numbers drop for single speed air handler, maybe a step up one?

There used to be rebates available for furnaces with blower motors. I don't know if they are still available.

mike, we wrote at the same time, everything is high here unfortunately, its a smaller town.

Performance 16, 2-stage

25HCB648A003 heat pump
FV4CNF005L00 air handler
TP-WEM01 thermostat

AHRI # : 6936859
Cooling Capacity : 47000
Heating Capacity : 46500
SEER : 16
EER : 12.5
HSPF : 9

$9100 ($500 rebate not included)

. (I may have accidentally deleted a comment below...). Trying to condense all of this..

Note that any cooling system removes humidity. Today's more capable systems, with a minimum of a VS blower, are able to do it better.

Any well-designed system will remove sufficient water when it is running hard. As they cycle more, humidity removal capacity goes down because lots of water re-evaporates and gets blown back out when the system starts back up. Condensation, in addition, does not start until the coils get cool enough and that is some time after the blower starts up.

With a variable-speed blower, the coils can be maintained at a relatively low temp with low air flow. That cuts the cooling rate, but maintains the condensation, water removal rate. The system, at the same time, is running longer.

The greatest effect is seen when the exterior temperatures are low and humidity high. That means at night plus early and late in the cooling season.

Thank you ionized. Our greatest need is not during those times, and I shutter at the words "reduced air flow." Our greatest need is our very long cooling season. And I want to feel cool air when its so hot, not in a trickle either. I don't run the system much in early spring and late fall.

The condensation on coils is interesting, I wonder if that is the stink we get when it is very cold (happens 8-10 times a year, our winters are mostly mild) and the system runs and runs and runs... I manually turn on emergency heat to fry up what is on the coils every few days and that takes care of it. But its the opposite of what you say, this happens after running for extended periods for heat. Our heat strips on this unit are not great, and never kick on unless we ask for several degrees warmer (but it won't happen if its super cold), or manually do it (then I have to remember to change it back).

Mike and others, I just noticed in rereading that there are multi-speed and variable speed air handlers. Are multi speed paired with single speed compressors, or just 2-speed?

A multi-speed air handler should be compatible with both single stage and 2-stage condensers. The configuration should have an AHRI directory listing if there is any doubt.

You should not have to worry about reduced air flow. The thermostat will instruct the air handler to go to the maximum air flow whenever it is necessary to keep the temperature at the desired setting. In the case where the AC is cycling on and off to maintain the temperature at 70 degrees, the air handler will initially start at a lower speed. However if the temperature setting is not reached in a short period of time it ramps up to a high speed, and then may ramp down to a low speed at the end of the cycle.

If you were to get a variable speed air handler and a thermostat that has a cool to dehumdify feature then you may get more reduced air flow operation. But that is actually a good thing. For example if the thermostat is set to 70 degrees and 50% humidity, and the room is at 60% humidity, the thermostat will operate the AC in order to bring down the humidity to 50% even though the house is at 70 degrees. Operating with reduced air flow helps keep the house from over cooling. The low air flow is quieter. You may not even notice the AC is operating as it is doing its job.

Is the basement very humid? You may have a leaky return duct pulling humid air up from the basement. The return duct should be sealed. Consider getting a dehumidifier for the basement connected to a drain. That may help the humidity problem in the house.

If there is no zoning, then the master bedroom is not going to get any additional air. The AC will operate until the thermostat indicates the temperature setting is reached.

OP, if you experience the operation of a modern, forced-air HVAC system, I think that you would be impressed with the comfort that a quiet trickle of cold air can do for your comfort. Furthermore, a trickle of cold dehumidified air can do wonders for comfort in shoulder seasons in humid areas like yours. You will still have your full CFM blast available if you need it for a fast temperature reduction in hot weather.

As said, you get the proprietary top and extra 2 yrs on compressor warranty with the XLi condenser series. If you don't have snow storms or lots of trees, I would not pay extra for the XLi series. I would want a 3.5 ton sgl stage XR16 HP or 4 ton two stage XR17, both with best matching var speed air handler. If going with 4 ton XR17, ductwork both supply and return should be looked at as far as the extra CFMs. Also, you might need a new and correct sized refrigerant lineset. I would want a filter cabinet like Trane's Perfect Fit and XL824 thermostat set up for dehumidify on demand in AC cooling mode. For your location, with moderate winter climate, probably a 10 KW heat strip. You should be aware that both of the models I listed are available through sister company Am Standard dealers, identical except for cabinetry and badging.

IMO

Thank you tigerdunes! questions: 1) what swings you from XR16 as opposed to XR15? 2) do you have an opinion on 2-stage Performance 16 by Carrier, it comes in $900 less than XR17, 3) how do XR15/16 compare to Performance 15 by Carrier? 4) I see mentions of pairing XR13 w/VS handler, opinions?

I am wondering if I need more quotes... I only have 1 each from Carrier and Trane dealers (more quotes coming from him). I can get another Carrier quote (since upthread it was mentioned that the quote was high), a Bryant quote, and an American Standard quote. I found 2 of the 3 on acca.org site, the Bryant dealer isn't on there but has a good reputation. Unless I get lower quotes, the higher systems (Infinity and XR17 and up and XL) are just too expensive. The 2-stage Performance 16 would be our stretch, I'm leaving it as a possibility. So as of right now, Performance 15 (single stage/VS handler/Carrier Comfort thermostat, non-programmable), Performance 16 (2-stage/VS/Carrier Cor thermostat), XR15 (single/VS need quote for particulars), and XR17 (2-stage/VS/need particulars and this is $1600 more than XR15 and most expensive in this lineup). So higher SEER single stage/VS vs. 2-stage/VS.

You have TMI now (too much information). I think Trane makes a better HP than Carrier especially close to coastal location.I expect Trane's XR15 will be discontinued in favor of the XR16. Use your negotiating skills with Trane dealer. Bryant same as Carrier. I would get a quote from an AmStd dealer. As said, they have identical to Trane's XR series models. Quality costs. I don't think I can offer any more help. Good Luck!

IMO

Thank you for your help!

Whatever you decide, be sure to get a variable speed air handler and a thermostat with a dehumidification setting to improve humidity removal. Don't worry about "reduced air flow", the manufacturers know what they are doing.

Thank you sktn77a! Carrier guy called today... I think the only system that has the level of thermostat you are talking about is the $9100 Performance 16 2-stage. We are choking on the prices tbh. He did say in our area that 55% in house humidity levels are the best that can be done with any system. That is funny..... I have no trouble getting that or below with my builder grade single/single Carrier model. To muddy things up, Trane quote came for XR17 at $9,000 ($1000 less than verbal). But Carriers are supposedly more quiet, and that is important too. Did I say I loathe car shopping, and this is looking like the same... I don't know why they don't give their best price right away, its obvious we are not rich...

The system we are leaning toward wouldn't have humidity control from thermostat, here are particulars:

Performance 15 (15.5?)25HCC542A003
FV4CNF005L00

10 KW Fan Coil Heater 240V/1PH
Carrier Comfort Thermostat
Non-Programmable Heat Pump

AHRI # : 6938234
Cooling Capacity : 42000
Heating Capacity : 41500
SEER : 15.5
EER : 13
HSPF : 8.5

$7800 less $500 rebates

As said, if you want something less expensive, look at Carrier's Sgl stage 3 1/2 ton Performance 15 paired with FV4 var speed air handler and Carrier Edge Thermidistat. 3 1/2 ton Trane XR16 paired with TAM7 var speed air handler and XL824 Trane stat. The comment on humidity is pure unadulterated nonsense as long as sized correctly. Both systems very comparable HVAC.

IMO

tigerdunes, look above, is that it? (I edited while you were typing). Sizing: Single speed is 3.5 ton, 2-stage is 4 ton, I can't imagine 3 ton being enough, so I think we are sized fine. I do wonder about 4 ton being overkill. Our area strongly favors Carrier, I looked at authorized dealers for both companies... over double for Carrier. I will get a quote from Trane guy for XR15/16, verbal is as expensive as 2-stage Carrier.... and both are higher than we would like to spend. I am keeping 2-stage on the table for now, but need really really good reasons to go way over budget.. remember I polar blast and was happy with the builder grade (I actually sit under the vent!). I do go back upthread and reread to refresh my memory as well so don't feel the need to repeat. I really appreciate all the feedback!

3rd quote today!! All of you would be pleased. He took information to do the manual J (no one else has done this). It was the most thorough inspection of all three. Authorized dealer, stellar reputation, no price haggling, over $1k less, in fact, Carrier Performance 15 & 16 quotes of other dealer are just a few hundred under Infinity 15 & 16 quotes of this one. I get model numbers on the quote he is sending after doing calculations, but the Performance 15 models are the same, we checked, $6184 after rebates. That's more like it.

You appear to be in love :-)

nice Carrier system but has poor to mediocre HSPF heating efficiency. Because of that, I would want the 006 size FV4 air handler. See below. And insist on Carrier Edge Thermidistat for superior control of inside humidity in AC cooling.

6938234 Active Systems CARRIER AIR CONDITIONING PERFORMANCE SERIES PURON HP CARRIER AIR CONDITIONING 25HCC542A**30 FV4CN(B,F)005L 1225 42000 13.00 15.50 41500 8.50 26200 1 HRCU-A-CB 341 985 Yes

7021410 Active Systems CARRIER AIR CONDITIONING PERFORMANCE SERIES PURON HP CARRIER AIR CONDITIONING 25HCC542A**30 FV4CNB006L 1225 42000 13.00 16.00 42000 9.00 26200 1 HRCU-A-CB 331 942 Yes

IMO

TD, I checked on that, I can't get 006, there isn't enough room in the attic with pitched roofline and the air handler has to fit through attic opening... The service/tech guy (this company trains their service techs to quote, they have one price for all customers, so yes ionized, true love) has the same handler, actually with the Comfort heat pump, and lives close to me, says he is nice and warm in winter, and has greatly reduced electric bills. He suggested that combination, but with rebates, its actually less money to upgrade to the Performance 15 heat pump. Stay tuned, I'm writing for our BTU requirement, and then will post model numbers of Performance 16 and Infinity 15, although we are leaning strongly to the Performance 15.

Understand...what is attic opening?...Pay attention to thermostat recommendation...

TD

TD thermostat is Edge (other high quote was Cor), attic opening is cut out in hall ceiling accessing attic, (not attic stairs). We came in between 3.5 and 4 for need, he still feels 3.5 is plenty the way its set up and that we have been happy with 3.5.

Performance 15 heater FB4-10-1, control TP-PRH-01
Our cooling requirement is 42,124 BTU and heating is 43,910 BTU, so numbers are very close.

Hopefully its all good, I pulled the trigger :D because one opening next week, and I got it :D we have another heat wave coming and I'm finished worrying it will go out and having to have thermostat higher.

Its in!! Humidity is 41% in my house! Mike, LOL still on 70 degrees... The unit is running almost non-stop since it was 100 today (at midnight still 83), and 90 in the house during installation. Awful. But so far, it feels great, the unit is very quiet, inside and outside. The techs said they were quite surprised the old unit was working, there was quite a bit that was wrong. We have a heat wave starting tomorrow, and they were sure it wouldn't have made it. Phew. Get this, they said "your unit has never been serviced." Ummmm we have had several service calls, in fact, one less than a month ago, in and out in 15 minutes, evidently service calls done right are an hour or more... This new company has very reasonable service plans (we get 2 calls included in price), they truly clean the coils every six months, and check everything and give you filters. Cool. I didn't know anyone did that...

Everyone, thank you for all of your help. I'm very grateful. I'm definitely an educated heat pump user thanks to you!

You have a nice system...if it is keeping up in this extreme heat that your area and mine is experiencing, that is a good sign and with low inside humidity. Outside condenser is large isn't it? Can't recall how you filter your return air? Please clarify. Enjoy your new HP system. It should be very quiet.

IMO

Congratulations! How does it feel to live in 40% humidity? Maintaining 70 degrees while it is 100 outside is very good. Those conditions are above design conditions so the AC should be running non-stop.

It sounds you have found a good installer who has fair prices. Good work on doing you homework.

Stay cool and enjoy the rest of the summer.

OK Mike, the thermostat was off by 2 degrees, so it was 72... since it was off, the humidity reading could be off a bit as well (right now, my digital thermometer says 72.5, 53% humidity and unit just stopped), the quality something guy is coming next week for a full inspection of everything. It is very nice in here, oh, how I missed my cool air. Even at 100 degrees outside, setting 72 deg. it is not running non-stop. I will watch, do you have input what to watch for?

TD: The outside unit (3.5 ton like last one) is larger and very quiet. Return air, we have the white cloth type filters on the returns (3), not the thick pleated, or the cheap ones. The installer cut out the mesh filter on the air handler, he said he doesn't like them, they come apart and get into the fan. I don't either, in an apartment we lived in, I found that mesh thing, it was filled with mold. Also, I'm not going into that attic to change anything. There are "boxes" feeding into the handler, they built new ones. There was another he showed me he didn't like, he built another one (unless that is included in the other two).

TD: Can you post back about humidity control (it might be 50s, that is what my digital thermometer says). They said to keep it at 60% because I cool so low, and that would keep the fan only from running.

There is way more air moving around, WAY more, as in a few whistling/clanging vents and returns, and a few vents which have quite a lot of air coming out of them. There are dampers installed, a few were cut back today, we will evaluate more on our own, and when they come back next week to check everything.

The thermostat temperature reading could be off. On some thermostats, like my Carrier Infinity from 2009, the temperature display will round up or round down the temperature reading whether you are in heating or cooling mode. I don't know if your thermostat has an temperature adjustment. What's more important is your comfort.

Accurate hygrometers (humidity gauge) are expensive and have to be calibrated. I would not be surprised to see a 5% difference in readings. I don't agree with the suggestion of keep the humidity at 60%. Your house will tend to be dry since you like it cold and the AC will need to run for long periods of time to keep it where you like it.

Keep note of how many cycles per hour you are running. Constant on and off is hard on the condenser. Ask the quality guy how many cycles per hour are set in the thermostat. Do a visual inspection of the installation. Does it look neat and clean to your eye? If the line set covered with insulation? Do the line set solder connections look solid? Is the outside condenser level and sitting on a stable pad? Do you know how to change the filters and which type of filters to buy?

It sounds you are off to a good start. Let's hope is stays that way for a long time.

Susan I agree with Mike. You have a new system. You need to take it out for a test drive. You need to learn your new system. i would be interested in runtimes and number of cycles/hour. A humidity level above 50 can be problematic both in comfort as well as providing an environment for mold growth. I would set your thermostat at 72-73 degrees and a humidity level of 40-42% RH. You want to verify with dealer that independent dehumidify on demand has been set up correctly. On 1" filters, I recommend the pleated models with MERV rating of 10. No 3M filters. They should be checked every other month and changed if indicated. Not clear about the box on your air handler. If you have a box filter on your air handler, you don't need the 1" filters at all. One or the other, not both though. You should have zero whistling, this should be pointed out to inspector when he comes back out to check install. I suggest you make a written list.

IMO

We have the correct filters for the returns, and there aren't any on the handler. New platform for heat pump, everything very neat and tidy.

It would do no good to use the humidity on demand since currently, the thermostat says the humidity is low 40s%.

Run times today, around 4-6pm, 98 outside, thermostat set at 73: off 15 min/on 30 min/off 15 min/on 33 min/off 13 min/on 28 min.

Your runtimes and cycles/hr sound good. You are mistaken regarding dehumidify on demand. I have given you the best and correct advice on that. Your decision though to follow up on that. For some homeowners it is a difficult feature/concept to understand.

IMO

I looked at dehumidify... it won't go lower than 46%, so I set it on that, but already it said humidity was 41-44%.

If you are serious about measuring humidity, then you need to calibrate your instrument. There are YouTube videos showing how you can do this. I am skeptical your house is at 53% humidity when the AC is running for long periods of time and the temperature is in the 70-72 degree range. Is certainly possible but unlikely.

The cool to dehumidify feature works well on those mild summer days when it is overcast and raining outside. On those days it is not hot enough for the AC have long runs so the humidity tends to rise. I am comfortable when the temperature is 78-79 degrees so it works well in my house. You however like it below 70 so it would be a rare occasion if the humidity is above 50%.

3.5 ton? My 2 ton system cannot lower house temp below 76f on 90f day. I suppose if I had a 3+ ton system maybe house would be cooler? Or run ac 100% at night?

stoveguyy, you may know there are other factors in measuring heating and cooling loads and equipment size requirements, as per the various load, duct, and system leakage standards. Unless you're talking about a 2 ton system in a 5000 square foot house, there are likely lots of retrofit projects that could be done to improve the efficiency and performance of the system that you have.