"Also there was no load calculation done by ANY of the three companies I received quotes from. Is this normal? SHould I be concerned?"

Normal, unfortunately yes. The right way of doing things? Absolutely not. Many won't put the time into doing a load calculation. There isn't really any money in it for them as part of a free estimate, and if there weren't any previous comfort concerns, many will go with the same size or similar. Good load calculations do not take very long to do relatively speaking if you're using the right software.

Since you mentioned the office stays warmer, I'd mention this. Is any of the ductwork accessible? It should be examined for proper sizing. Any mention of the ductwork at all (changes that may need to be made, condition, etc.) by any of these dealers? Since this is an upstairs system, am I wrong to assume the ductwork is in the attic? If it isn't sealed/insulated well, you're losing capacity and efficiency and in the longer duct runs (office perhaps) it can mean decreased comfort in that space. Proper sizing and layout are important to system operation, yet often overlooked.

You may want to pursue further estimates. Post back the model numbers when you get them.

This post was edited by ryanhughes on Tue, Apr 9, 13 at 18:24

I should have mentioned that the dealer proposing the infinity , looked at the duct work and found that it it is branching off another piece of ductwork that is much farther away from the office. Included in the price is the moving of that branch much closer to the air handler to increase output.

They proposed to add another supply or a heat return for a couple of hundred bucks later on if it does not help.

It is always good practice to perform a load calculation. Proper sizing is important. Too big can be as bad as too small. In a replacement situation you can use the size of the current equipment as a guide.

What is the current size of the condenser, where is located, and how well has it performed? What is the size of the house?

I don't consider a quote to be valid unless it contains all the details of model numbers and all the work which be performed.

Is the Goodman quote for a 2 ton unit or is that a typo?

Carrier Infinity is top of the line. It is excellent for humidity control. The Performance model is also very good. Both of these model come in one and two stage configurations. The price of the Infinity system seems on the high side if it is after all Carrier and local rebates. The Goodman equipment is considered second tier. It is not a popular choice in this forum.

Sorry the goodman is a 3 ton unit and was a typo.

The original size was 2.5 Ton 10 SEER conditioner, air handler located in attic, and has always struggled to maintain the temperature upstairs. There have been many nights that I felt like the upstairs was not nearly as comfortable as the downstairs.

We are also doing some work upstairs, which would add an additional 200-250 square feet onto the upstairs. With all of that information it was suggested to go to a 3 ton instead.

Yup the infinity at $9,000 already has the power, federal, and carrier rebates applied. The base infinity thermostat only costs around 179. I did discover that the thermostat that they are proposing goes for 500-650 online, so not sure if that is what is making it seem high.

I would like to see the model number of both outside condenser and inside air handler for the Carrier Performance system.

What model thermostat?

I would stay away from the Goodman.

Post back.

IMO

These are the proposed models:

The Carrier Performance is the 24ACC636 with the FV4 air handler. If I go this model, I will be using my honeywell vision pro, so not sure what the thermostat is.

The Infinity is 24ANB7 with the FE4 air handler. This comes with the SYSTXCCITN01 thermostat.

Skalek

If sized correctly, I like this selection very much.

Here are the AHRI AC directory numbers.

3657131 Active Systems PERFORMANCE 16 PURON AC CARRIER AIR CONDITIONING 24ACC636A**30 FV4CN(B,F)005 34200 13.00 16.00 1 RCU-A-CB 253 Yes

If you want superior dehumidification, I would want Carrier Edge Thermidistat over the HW Vision Pro model. It would be worth it!

May I ask how you heat and with what fuel?

Post back.

IMO

OK thanks for the suggestion on the thermostat. I think the edge is what they were planning on using, so will just let them continue to use that instead.

Few questions:

1. You think the Performance suggestion would be a better solution than the Infinity? The 2000 difference is significant but spreading that cost over 10-15 years is not that bad if the comfort level is really that different.

2. Any idea how the pricing looks? Fair, slightly expensive, expensive?

3. I have been reading a lot of the posts here on the forums about requiring the air conditioning company to do a Manual J calculation. I have had 3 different air conditioning companies come in to give a quote and not one did one, but instead based it on my existing AC and what near plans for the space. With that said, should I not use a company that does not do this calculation?

4. Another AC company recommended American Standard. Still waiting for the model numbers on those, but it was a 3 Ton Single stage unit. How are the quality of those units?

I heat with gas furnace baseboard heaters.

Thanks for looking at this for me.

Skalek

Southern boy always glad to help a Yank...

I try to advise and suggest like I would spend my money. Generally speaking I think one gets what they pay for.

While the Infinity system is very nice, I doubt if one could justify the price difference with any reasonable payback. The major differences are the diagnostics, the two stage scroll compressor, and the Infinity controller. If money is not a concern then take a hard look. I could even give you another option if interested that would be less money than the Infinity but more than the single stage Performance 16 model.

The Performance system you were quoted is very nice. It is single stage. See link below. The Edge thermidistat will give you "DOD" dehumidify on demand which is great feature for dehumidification in the summer.

You need to verify the air handler model in the system I listed. Important!

It is also important that dealer thoroughly inspect your ductwork system as to size-both supply and returns and insulation properties since ductwork is in attic. Especially since you are going up in size by 1/2 ton. How many returns does upstairs have? How do you filter your return air now?

And to be clear, you have a nat gas boiler for heating?

Post back.

IMO

Here is a link that might be useful: Carrier Performance 16 AC

Trane and American Standard are the same company and equipment. The quality is equivalent to that of Carrier/Bryant. You need to compare similar models when shopping for prices.

Most companies will not do a Manual J calculation. Even when they do, there is no guarantee it will be correct.

How big is the house? Is this AC for upstairs only or the whole house? How much insulation is in the attic and walls? How tight are the windows?

As much as I like the Carrier Infinity, it would be hard to justify an extra $2000. The Infinity 2-stage will do a better job in dehumidifying and will be very quiet when running on the low stage.

You could consider the Performance 24ACB7. It is also a 2-stage condenser and can be used with the FV4 air handler.

5630523 Active Systems PERFORMANCE 17 PURON AC CARRIER AIR CONDITIONING 24ACB736A**31 FV4CNB006 36000 13.70 17.70

Should be cheaper than the Infinity, but I don't think there is a Carrier rebate with this configuration.

This post was edited by mike_home on Wed, Apr 10, 13 at 11:16

Thanks everyone for all the info. As I can see there is a wealth of knowledge that I definitely appreciate.

Tigerdunes, sure I would love to hear the other AC suggestion. From what I have been reading, I like the concept of the 2 stage conditioner as it seems that the benefits are quite nice (energy efficiency, temperature control, and humdity control). So I think I am definitely going in that direction. Whether it be infinity or another 2 stage conditioner is what I am deciding on at this point.

What makes the Infinity so much more ? I see its two stage, comes with a very fancy thermostat, and is very quiet. Would I get these same benefits, comfort, & dehumidification from any 2 stage conditioner though? The thermostat I am being quoted is $500 bucks on its own, which is crazy to me.

The upstairs has 8 supplies and 1 fitlered return in the hall with a 13 1/2 x 29 1/4 grill. I use custom sized merv-8 pleated filters. As part of this project, and in the cost already, they will be increasing the size of the return duct as they said it was only 13 inches and should be bigger.

Our house is heated with natural gas boiler.

mike_home, thanks for the great info. The house is approximately 3100 sq feet. The upstairs, which is the ac replacement, is 1092 square feet. Attic recently had a significant amount of insulation blown in. If I remember correctly, it was 18 inches of blow in (hate this stuff). Windows are NOT tight at all. Single pain and not sealed well. Its these old pela windows that have the shades built inside of them. They will eventually need to be replaced. The insulation on the external walls of the house are not the best either. Thanks on the suggestion for the 24ACB7. Would the 2 stage of this condensor offer the same dehumidification and comfort as the infinity. Or does the infinity offer more control?

Thanks again for all the info.

With 1000 square feet and 3 ton units being quoted (along with added costs of duct modification to support them), you definitely should look into getting a load calculation done -- especially since improvements in insulation have made. It is possible that even the 2.5 ton system you had before was oversized, as many systems are. Oversized systems are not energy efficient and do not dehumidify well. Many don't want to hear that their previous system was oversized when it had trouble keeping some areas comfortable. Some companies will throw more capacity at the situation and extenuate the current issues and/or create new problems. But system performance is dependent on many variables, including ductwork (size, insulation, layout) and installation practices. Since you obviously care about getting this done right, I would tell further companies you call that you are in need of a load calculation. If they don't want to, then don't bother with them in my opinion.

2-stage units do offer a noticeable improvement in all the areas you mentioned. As for the Infinity, the logic is pretty sophisticated in terms of dehumidification and control over airflow. But: sized, installed, and set up properly all three are important), you might be hard pressed to notice a huge difference over the Infinity system versus the similar 24ACB7 system with FV4C air handler AND TP-PRH thermidistat that tiger mentioned before. This thermostat can (and should) be wired to reduce blower speed as humidity rises too high.

As for American Standard/Trane equipment, I certainly am a big fan so you know what my answer will be. The quality is good. And I really think their Hyperion air handlers are superior to others on the market. I like the all-aluminum coils (there have been big issues with conventional copper coils leaking only after 5-7 years due to formicary/galvanic corrosion). Several manufacturers have switched to all-aluminum indoor coils and more have plans of doing so. The Carrier does not feature an all-aluminum evaporator coil (it is tin-plated copper, which is an improvement). Also, I do feel the electronic expansion valve (refrigerant metering device) in the Trane air handlers does a much better job controlling refrigerant flow through the coil compared to conventional thermostatic expansion valves, which sometimes are at the mercy of the installer if installed in the field and not factory installed (again leading back to the importance of a proper installation -- the Carrier FV4C will have a factory installed R410A TXV). The 500-position EEV gets the coil very cold without letting it freeze and facilitates greater dehumidification. You may want to look at the XL16i (2-stage scroll) with TAM7 air handler. The XL20i, while expensive, really is the "best" 2-stage system on the market in my opinion and has dual compressors for 50%/100% capacity staging (longer efficient runtimes, better dehumidification). While 2-stage scroll systems are nice, the dropoff isn't as much in low (~75% capacity), so still very important not to (potentially) be oversized even in low stage.

Please continue to keep us posted on how this goes. And good luck. No matter which system you end up choosing (single stage or two stage), Carrier or Trane (or some other mfg), when installed and sized correctly you should be very comfortable for years to come.

This post was edited by ryanhughes on Wed, Apr 10, 13 at 12:59

All good and I have to admit, overwhelming information. With all of this information, it leads me to more questions so I apologize for this.

Unfortunately, this AC that I am replacing is leaking freon so I need to come up with some solution as we are starting to get into the hot months here in NY.

With that said, at the end of the summer I am going to be doing a lot of work on my house, which I have gone over with the AV companies I have spoke to. This work could consist of:

1. Adding more square footage to the upstairs and downstairs of the house.

2. Changing roofline

3. Replacing Windows

4. Replacing the siding.

5. Possible removing the blown in and instead using other types of insulation. I hate the blown-in as its just a complete mess.

If it was a perfect world I would wait to buy the AC until all of this work was done, but unfortunately, I am stuck without an AC upstairs. One thought would be to throw money out the window and just charge the leaking condensor as necessary, which would at least allow me to make it through the summer and into the construction so I can properly install the AC that I would really need. I was told, though, by one AC company that legally they are not supposed to recharge an AC more than twice if there is a known issue. I am not sure if that is true or not.

From the replies I am receiving, I am assuming that some of you are in the HVAC profession. I would love to hear your advice as to what you would do in my situation, because I honestly do not know the right answer. You have a computer/computer security question, I am your man. When it comes to this I am lost.

It is hard for me to believe that a 3 ton system for your upstairs is appropriate based on the information you provided. So, I would get in contact with the company you felt the most confident in and discuss getting a true load calculation done versus guessing. Did the previous 2.5 ton run long cycles and constantly on the hottest days, or did it run short cycles (5-10 minutes) on warm days? Hard to account for your future addition in this situation (assuming you don't have all the exact plans for it yet). How long down the road may that be, and how long would you be willing to live with an oversized system (going 2-stage is definitely advisable here I think) are the two questions you have to ask yourself. Roughly how big would the addition be? If significant enough, it may be better to have the addition on yet another system (there are ductless systems available) and leave the existing systems alone.

That said, if they do the load calculation and are careful in the values they use, and it comes out to 2.5 tons, then a 3 ton dual-stage system would not be inappropriate, if not a 2.5 ton single stage system with variable speed air handler and humidity-controlling thermostat. If they are careful, I wouldn't be surprised if a 2 ton system with well-sealed and insulated ductwork would be the most efficient option. Even that is "500 sqft per ton" which is a long-debunked rule of thumb that ended up in many oversized systems being installed (and still does!).

This post was edited by ryanhughes on Wed, Apr 10, 13 at 14:28

I have the older generation Infinity controller. The new touch screen version is nice, but it is a pricey upgrade which is unnecessary. The real value is the embedded software of the controller. Its the algorithms in the software which are making the decisions to maximize comfort and efficiency. I have version 16 of the software. I am going to assume the algorithms in both controllers are the same. Unfortunately you can't upgrade the software.

I would think a 2 ton AC would be sufficient for a 1000 square foot upper floor. This may change if you have an office on the second floor with several computers.

Your old AC may have struggled due to a low charge. You should also carefully inspect the duct work in the attic. Flexible ducts are prone to leakage. Find out what R value the current duct have. The general recommendation is to use an R-8 insulated ducts.

If you are interested you can do your own load calculation for $49. Below is the link.

Here is a link that might be useful: HVAC Calc

It ran long cycles on hot days. Took it a long time to get it down to the temperature I wanted. When I set the temp to 69, it did feel like it the AC was constantly on. I don't remember it going on and off every 5-10 minutes, but I may have just not noticed it.

I will have the architectural drawings friday for the extension, but it should not add more than 200 square feet to the upstairs. That would put it at 1292 square feet for the upstairs. We plan on starting the work at the end of august beginning of Sept.

I am going to ask for a load calc to be done, but with a 2 stage, does that mean if I purchased a 3 ton, it would operate as a 2 ton unless needed? So if a 3 ton was oversized, and I only needed 2 ton, the only downside is a spent money I did not need to spend?

Thanks Mike. Is that HVAC-Calc software realistic? I do have a office on the second floor with multiple computers. On average that room is 4 degrees higher than the rest of the house.

I did the hvac-calc program and entered all the info as best as I could. If I am reading the report correctly it is saying 1 tons? That means it thinks i need a 1 ton AC for upstairs?

For what I have read HVAC-Calc produces fairly accurate results. A load of 1 ton sounds low. I would expect it to be in the 1.5 - 2 ton range. Check the input carefully.

You should some up the number of watts you are dissipating in the office and convert it to additional BTUs.

Hi All. Back again with a 3rd quote and a few more questions.

Only Company A (Carrier dealer) stated that we would need to rerun the refrigerant line in order to use 410A. The other proposal said they can reuse the line if its properly pressure cleaned. Is this accurate or does the increase in pressure require a bigger pipe?

I also received two other quotes and they are:

Company B: This company concerned me as they are telling me I should use a 3.5 by just eyeballing the house. When I asked about a load calculation his answer was he does not really believe in them. After being educated here, this was obviously a concern.

Choice 1: Rheem RANL-JAZ7 16 Seer single stage 3.5 Ton Condensor with matching air handler.
Choice 2: Rheem 13AJN 13 Seer Single Stage 3.5 Ton Condensor with x13 motor for the air handler

Other work: Install another supply in office and increase airflow to original supply in office.

Warranty: 10 year condition parts and 2 year support from AC Company.

Company C:

Choice 1: Guardian GDCGD30 2.5 Ton condensory replacement. Continue to use freon and the existing air handler.

Other work: Install a small heat return in the office, make their filter/return in hallway a little bigger, and increase airflow to original supply in office, clean coil in existing attic air handler.

Warranty: 5 year limited parts and compressor. 5 years full guarantee from air conditioning company on service.

Now, Company C is obviously 75% less than the other proposals due to just changing the condenser. I am concerned, though, as I have been reading that a #1 mistake is not properly matching the indoor equipment with the outdoor equipment. This company felt that the savings of just replacing the condensor outweighed any efficiency loss.

"When I set the temp to 69, it did feel like it the AC was constantly on. I don't remember it going on and off every 5-10 minutes, but I may have just not noticed it."

I just noticed this in your previous post. The typical indoor design temperature for cooling is 75 degrees. If you want it to be 69, then this will need to reflected in the load calculation.

Company B doesn't believe in load calculations so their method it just oversize the equipment and have the customer pay for it. You can scratch him off the list.

Company C sounds like the low bidder approach. They are providing a low end dry condenser and then filling it with R22. You can also scratch them off the list.

The general recommendation is to change the line set whenever it is practical. The line set can be reused only if it is the proper size and it has been properly flushed.