Am I correct that if doing 2 zones, it requires duct work?

Yes, separate ductwork for each system.

oh, then doing 2 zones is not an option. That means, it will cost me more. :(
I'll just wait for other folks here to confirm that 4-ton is the appropriate unit for me.

I'm also waiting for another new A/C vendor. Hopefully, I'll get a call tomorrow.

v1rtu0s1ty... as a homeowner, let me spell it out directly for you, as you seem to be missing it over and over. No pro here in their right mind would ever "confirm that 4-ton is the appropriate unit for" you.

Some said 5 tons SEEMS to high -- get the numbers checked. Some said 3.5 tons SEEMS too low -- get the numbers checked. Then, YOU came back and picked 4 tons. How did YOU arrive at 4 tons? With WHAT man. J numbers?

They don't know your house, how it faces, how the windows are built, what they are, how many there are, how high your ceilings are, etc. etc.

If they did that, they would be guessing -- and that is what they are trying to tell you to avoid. Get all the numbers, then decide.

Just got off the phone call from the vendor that quoted me 5-tons. He told me that the builder just told him to quote 5-tons. LOL. How I find out about this is that, I asked him to provide to me the manual J and HGL calculations and he couldn't provide anything. He told me to contact my builder and ask the builder to provide the manual J and HGL. Do you think it's proper to get the mj and hgl from my builder? Assuming I'm able to get this information, is it ok to share it to this post?

Anyways, the vendor is coming over tomorrow. I specifically told him to do hgl calculation and manual j. Also, another vendor is coming over tomorrow. This time, I won't just watch and listen to them, but I will keep asking. I know more now. :)

Ok folks, I contacted the Lennox guy. He explained everything on what he did. He did count all the windows, what types they are(single/double/triple) pane, low-E, size and to where those windows faces. He also considered where my house was facing. He also included the R38 ceiling. He also added the appliances load. He also included the number of people, however, he only loaded 8 people. He also included the walls and it's insulation such as the R13s. He also double-checked if I had a crawlspace but I didn't since it's full basement. He also mentioned that here in the city where I live, the temperature that should be used is 95F.

Oh, by the way, I asked him to change the 8 people load into 20 people load and his software recommended a 4-ton unit.

This is a good news then. The only situation that I need to address is what brand I should get and the cost too. From my understanding, they're all the same. He quoted me a 4-ton XC13-048-230 13-SEER Lennox for $3,141.

He was claiming that Lennox is better than Carrier. Hmmm. I've never heard of Lennox. I have heard about Carrier and I've seen some people's review about it and they say that it's been running for more than 20 years with minor problems.

Any comments would be greatly appreciated!

Your furnace is at the link below. It's a sealed, 92% efficiency unit, and is from Carrier's builders line. It's a good, efficient unit.

It does not have a variable speed blower so it cannot be used with Carrier's humidity control system. So, you do not have to lock yourself into a Carrier A/C unit (if you wanted that).

I'm just a Carrier homeowner, so I'll let the experts comment on the Lennox. But, seems to me that you now have the numbers from a tech you can trust, and that's WAY more important than a brand name!!!

Here is a link that might be useful: Carrier 58MCB series

Ok folks, the third Carrier vendor just left the house. He didn't do manual j and heat gain/loss calc until I told him to do so. He counted all the windows. He asked me what the insulations were. He will input all the information later once he reach his office.

Anyways, he measured and calculcated our sqfootage and he said that it was close to 3,300 to 3,400 due to the open space in living room which is 18ft high. He told me that builders don't include open space in sqft.

So, he told me that I should get a 5 ton. I told him that the other vendors did a manual J and hgl and came up with 4 ton unit. Then he responded with, if you put 4-ton, it will run everytime during summer. He also told me that he will enter all the info he had gathered on his computer to see if 4-ton is appropriate.

The Residential Carrier website says that this dealer is well-known for its experties in this area. But, again, how come, each vendors comes up with different results. :(

One thing to remember -- a properly sized unit WILL RUN most of the time in the very hottest weather. A unit that short-cycles on/off is very inefficient and sucks at removing humidity and will wear out faster.

And, make very sure a TXV (thermal expansion valve) is part of each quote. It is much more efficient than a piston-based system.

"a properly sized unit WILL RUN most of the time in the very hottest weather"

This info is priceless. :) I was under the impression that if A/C is running everytime, it's very bad. I was wrong then.

And YES, I will make sure that TXV is part of their quotations.

Thank you very much sir. :)

"And, make very sure a TXV (thermal expansion valve) is part of each quote. It is much more efficient than a piston-based system."

I asked the other vendor and he told me that TXV is not needed by Puron based A/Cs. If it was R22, then TXV can be used. Is this true?

That is not right. TXV=higher efficiency, because it regulates the flow of refrigerant.

LISTEN to what airsome said! If that Carrier dealer told you that, then WRITE HIM OFF!

R410a vs R22 has notjing to do with a TXV being way more efficient. It is WAY more efficient on BOTH!

Oh no!!! This guy then doesn't know what he's talking about.

By the way, this guy is coming over on Tuesday. I don't know what's taking him so long to come over. Maybe, he got intimidated when I told him that he should do manual J and heat gain/loss calc on the spot. So looks like, he's doing some research.

I contacted the vendor that installed the furnace. He explained to me everthing they did to our house such as those air intake device that runs every hour for 10 mins to pull fresh air from outside. He also explained the infiltration, the insulation. He mentioned to me those air returns, the openspaces in our house. So basically, he told me that it was them who design the house. He told me that they use REZCALC to do the design of the house. I don't know what that is. He told me that house needs 42000 BTU. According to him, I would need a 4.2 ton unit however, there is no 4.2 TON unit neither their is a 4.5 ton unit. I can go either 4 or 5 ton.

He explained that if I go with 4-ton, and temperature outside is at 95F, I won't be able to get to the temperature I want which is 75F. He said that manual j is designed only to be 15F cooler.

So since these is the vendor that designed the airducts, furnace, should I follow his recommendation of 5-ton? If you recall folks, the other vendor said that the furnace was properly sized and installed which is unusual.

Sorry folks for this multiple questions. I hope you can still help me. :)

"He explained that if I go with 4-ton, and temperature outside is at 95F, I won't be able to get to the temperature I want which is 75F. He said that manual j is designed only to be 15F cooler."
- The 15 degree F difference in temperature is NOT from the outside ambient temperature. It is the difference in temperature of the INSIDE air before the evaporator coil versus after the evaporator coil.

So going back to my question. Is it true that a 4-ton unit won't be able to reach 75F when temperature outside is at 95F?

He also asked me if we open our windows during summer. He asked this because he was concerned about the recovery time. I think this was the reason why he was saying that the 4-ton unit won't be able to cool our house to the temp we like during summer.

So what are your thoughts about this folks?

Thanks again.

He asked you if you open the windows in summer because that brings in humidity. There's two kinds of heat a compressor removes -- sensible heat and latent heat. Latent heat is the humidity.

It takes a lot longer to reduce the latent heat (remove the humidity) than it takes to reduce the sensible heat (lower the air temp). That's why you should not open your windows during cooling season -- it will run a lot longer if you do. That's also why oversized units are uncomfortable -- they reduce the air temp so fast (they reach the set point of 75F, for example) that they cannot remove enough humidity. So, the house feels cold and clammy.

A correctly sized unit runs longer and at lower speed, which enables it to remove the latent heat of humidity more efficiently, all the while gradually lowering the sensible heat till it reaches your set point of 75F.

The other question I'll leave for the pros here.

Oh, another thing he mentioned is about the R-22. He told me not to be worried about it. The www.icor.com will be selling NU-22 starting 2010. He said that NU-22 is new and an EPA approved version of the R22. He don't like R410 or Puron because it's 500lbs something. I couldn't remember what he explained.

Here are the prices.

24ABR 13-seer 4TON $2,594
24ACR 13-seer 4TON $2,894

24ABR 13-seer 5TON $2,819
24ACR 13-seer 5TON $3,144

So guys, based from the information I got from the vendor that designed our heating, 42000BTU for the cooling, should I get a 5-ton unit?

So dallasbill, in response to your last post, it is not true that a 4-ton unit cannot handle 75F degrees inside the house.

So guys, based from the 42,000 BTU that they have on their design, would a 4-TON unit be sufficient for cooling?

42,000 btu's = 3.5 tons.
Whether or not this will be enough to handle your needs cannot be evaluated here. It is dependent on many factors, such as insulation, window type, # of windows, which sides of the house the windows are on, which way the house faces, how much shade you have, building materials, wall thickness, type of siding, etc; too many to list here!
You will have to rely on your contractor's judgment or do the complete load calculation yourself.
Regarding R-410a, go here and click on "Myths...": www.410a.com.

"So guys, based from the information I got from the vendor that designed our heating, 42000BTU for the cooling, should I get a 5-ton unit?"

"So guys, based from the 42,000 BTU that they have on their design, would a 4-TON unit be sufficient for cooling?"

51 posts into this thread and it just runs on and on and on and on and on with the same question. You have flip-flopped your decision 17 times. You are asking the pros on this forum to decide for you when they really can't because they don't have the calcs in front of them.

The load calculations need to be done. It's the only way to find out if the correct size AC will work with the six month old furnace. If the furnace is oversized the correct air volume needed to operate the AC may not be available.

When you go to www.410a.com you will see that NU-22 is not a viable option.

>>>"51 posts into this thread and it just runs on and on and on and on and on with the same question. You have flip-flopped your decision 17 times. You are asking the pros on this forum to decide for you when they really can't because they don't have the calcs in front of them."

I was under the impression that providing you with 42,000 BTU result from the heat gain/load calculation done by the designer, we will be able to decide with tonage I should get. What am I missing?

I was just simply asking if 4-ton is enough for a 42,000 BTU load calc. But got confused when the designer told me that if it's 42,000, I should get a 5-ton.

I'm very sorry if it's over and over and over. I just want to really make sure that I will buy the proper unit.

>>>"When you go to www.410a.com you will see that NU-22 is not a viable option."

Earlier on this thread, someone mentioned not to forget about R-22. Now, with the response above, NU-22 is not a viable option. So guys, which type should I really buy, R-22 based or Puron based.

Do you live next door to a guy with an RV and a big stone retaining wall?

...sorry... wrong forum...

This has got to be a set-up. The tail is wagging the dog.

I think you are confusing the issue here. You were quoted a 3 ton ac system which is 36000 Btu's. You were quoted a 5 ton system which is 60000 BtuÂs. 42000 is 3.5 tons.

Sizing a system is an art that many contractors just guess at. They then make their calculations match what they want to sell.

If the original installer calculated 42000 BtuÂs needed and the Lennox calculated 36000 BtuÂs needed, and 2 other companies also calculated 60000 BtuÂs needed, then someone is guessing. Since most guys guess, I would ASSUME (ASS out of U and ME) that either the higher sized equipment or the lower sized equipment is what is needed. Duh... In short do your own math. Make a best judgment call on the math. Quit trying to guess.

Forget the brand, go with the best installer. While I donÂt care for Lennox, if you think he is the best, than use him. You may consider using the original installer? Normally the builder gets money from all addon sales. You have eliminated the builder at this point. Get a new bid. If the original installer is firm on his price, forget his bid.

I have not read through all the posts above but the data you supplied appears to be in error.

You showed...

Carrier - 24ACA3 13-SEER 5tons $2800
Carrier - 24ABA3 13-SEER 5tons $2450
Carrier - 24ABA4 13-SEER 5tons $2600

Those Carrier model numbers appear to be 2 ton units, not 5 tons.

those are the new carrier numbers.
the 24 is the unit designation, not the tonnage.

24 - product series (24 = ac)
A - product family (A = residential AC)
C - tier (A = comfort series)
A - major series (A = Puron)
3 - seer rating (3 = 13)

whats missing is the tonnage which is right after the 3..

so, a 5 ton would be 24ACA360. I work for a carrier dealer and the new numbers still confuse me.

freaking vendors, I hate them all. The first vendor that quoted over the phone came over today because I asked him last week to do the manual J and heat gain/loss. It took him 1 week before he was able to decide when he can come here. Maybe, he did some research. LOL.

This guy is lying. He arrived around 8:30 this morning. He counted the windows but he didn't measure the windows. He didn't even measure each room size. Then lastly, I caught him that he is just really guessing. He was telling me that I need a 2-stage unit. I was frank that I told him he was wrong. From my research(I hope I had the correct info), you need a 2 stage furnace for a 2-stage a/c. A 2 stage a/c will not function well on a single stage furnace. I don't know if it's even possible. Anyways, he said that he'll come back to for the load calculation and mj. I received a call around 4pm. He told me that he arrived at 50,000 BTU.

So, I have a 36,000 calculation from vendor B. I have a 42,000 calculation from original installer. Then I have a 50,000 calculation from vendor A. Tomorrow, I will receive a call from vendor C. Oh, vendor C was here yesterday. He did the same things but even more. And he explained all the things you guys have told me and have been telling me over and over. :)

Tomorrow, after vendor c's call, I will present to wifey and hopefully be able to decide which vendor to go with.

The only choices are vendor B, C and original installer. Vendor A is out of the ballgame.

Vendor B is Lennox while the other vendors are Carrier.

Thank you very much everyone for all your help. I have learned a lot. I also would like to apologize because I keep on asking the same questions over and over. ;)

So what ton should I get? Hehehe. :)

I'll keep you guys posted.

I saw the abbreviation OP. Does it stand for owner/prop. ??

You guys told me earlier that I should make sure a TXV is included in the quote. The vendor told me that the Carrier Puron coil has a built-in TXV valve? Is this true? And I told him that TXV has nothing to do with R22 or R410a. But he insisted that the Puron coil has the built-in TXV. What should I do? I don't know what to tell him in order for him to provide to me what I want. Maybe guys a part number that you can tell me will help?

Please help.

Check for a local NATE certified company/technician.

Here is a link that might be useful: NATE website

Call the Carrier 1-800 number and ask them that question re: TXV. You can find it on their website.

Baymee... OP means Original Poster -- the person who started the thread.

Dallasbill, I was able to talk to Residential Carrier and yes, it comes with factory installed TXV. Model number is CNPVP-6024-ACA.

Should I request for an 8 gauge for the electrical wire?

I'd hate to be the guy that has to warranty your system. :)

Hey Virtuosity, I'll be in chicago on April 9th, want me to take a look and tell you what ya need?

Hi blacknumber1, that would be awesome but I have already decided this morning. It will be installed on Monday afternoon. It would be the 24ACA360 5 ton. I decided with 5t since the 3 vendors that did the manual J and heat gain/loss calc came up with 5. Only one vendor came up with 4 ton.

Does that mean that this never-ending post will finally be put out of its misery??

Make sure you get yourself a 16 gauge, in case you don't like the installer's 8 gauge work.

Then again, maybe the installer should have one instead... ;-)

Is it over? I must be dreaming............

nope, not yet, I have some few questions but not about a/c anymore. I'll post a new thread.

Thanks for everyone's help. I'm so sorry if I was so stupid. Maybe the moderator can delete this thread or put it in the archive.

Nothing like a good 16 gauge to take out frustration on an old water heater.

Hwy I just thought of a new use for old units.

I would suggest that you are better off with the 5 ton.

Disclaimer: I am not an installer, or edjumacated in HVAC.

I have a 3,000 sq ft house with a 4-ton unit in Sacramento. When it is 105 outside, the AC can't cool upstairs below 80. My electric bills are outrageous. On the hottest days, I have to set the AC to 71, and it fights a losing battle all day long - occasionally it got over 80 inside.

2.5 year old house. KB Home. Beutler AC - they tried to convince me they did the manual-J calcs, but their numbers did not include the heat gain from my 3-car garage (west facing, with bedrooms above it, they claimed it was irrelevant), and they only factored 2 people "load" (no appliances) into a 3,000 sq ft house.

I'm having several companies come out; I'm sick of my wimpy 4-ton (LOUD, cheap, 10-SEER - bare minimum for 2004). I want to be able to cool the house DOWN, not merely have the AC heat it up slower than outside.

hi goglen,

Baldonie told me to go with 5-ton. He said that most of the time, 4-ton is weak or is always under power. I went with the 5-ton after combining all the information I have gathered from different vendors. I also made sure that coil was a Carrier with a factory installed TX valve. They also changed my thermostat with a time-delay feature. Now, I have 7 days programming.

The guys really did a neat job. I was very happy with it. Man, the Carrier 24ACA-360 condenser is massive but looking in the inside, it's almost empty. LOL.

You should have posted your experience earlier so I could finalized. :) jk

If you second floor is not cooling, you most likely have a poor cold air return on the second floor. Increasing the condenser size will make the condition worse. You must return 60% of the air, in a 2-story home, near the ceiling on the second floor. Hot air will float on the cold air. Without a process to remove the warm air from the ceiling the cold air will stay in the first floor. If you can feel your head getting hot as you climb the stairs and air is comming from the vents, it's the return. Poor air flow is common place in new construction homes.

New construction homes are sized for A/C using the worse case sonero. Front facing SW because that is where the summer heat comes from and most of the windows are. Winter time loads are based upon the front facing NE. Now, every home in the development will get that HVAC package plus a little for Grandma.( 1/2 ton to a ton extra and twice the number of Btu's in the furnace) Why? Because neighbors will compare sizes and the developer does not want to explain to the customer about Manual J, if he even knows what it is. A good load calc program will allow you to rotate the building and see how the direction the home faces changes the load.

SEER tells you how efficiently the equipment converts electric to cooling. Btu/$. 13-SEER will give 13,000 Btu/ kW. 15-SEER= 15,000 Btu/kW. etc. If you think a larger A/C unit is better, you are mistaken. A properly sized unit will yeil a home with lower humidity and more comfortable. If the home needs 2-/2 tons and 5 tons is installed, cooling costs will be the same if identical SEER units are installed. the 5 ton unit will run 1/2 the time amd the house will be more humid. Remember, SEER= Btu/$. so operating costs will be the same, you will not be as comfortable and your wallet will be lighter than it should.

The internet is a good way to find out about contractors and a poor way to size an air conditioner. Find a responsible contractor, have him do a Manual J (heat load) and go with his recommendations. Do not pay attention to what the guy next door has. He may have a friend that knows a guy that installs A/C. Run like a deer from that guy. You may get a good price but no comfort.

BIGGER IS NOT BETTER. When it comes to air conditioning.