I am replacing a 30 year old AC unit and I have had 4 estimates. 2 of the 4 people did not even take any measurements and the other two took a lot of measurements. I am leaning towards the ones that took measurements, but they are giving me two options. I live in Florida. Here are the two options:

  1. 3.5 tons 13 seer straight cool
  2. 3.5 tons 13 seer heat pump

What is the difference between the above two?

Does anyone know some important questions I could ask the installers to see which one maybe more qualified or knowledgeable in installing the unit

I found paperwork on the house and it indicates that a 3.5 ton was installed in 1984.

The two people that did not measure apparently were salesmen.

One from sears told me this:

OK great give me a call or send me an email when you ready. You currently have a 2 Ton and I can see going to above 1/2 ton more or a max 1 Ton more not 1 1/2 Tons more. I will install what you want, and our system and service will be better than any company out there. When you contract with Sears you don't get a lot of plastic and thin metals you get a good quality system that will last.

I don't understand how Sears can tell me I have a 2 ton when I have a 3.5 ton. Something smells fishy here?

  • Yep, best to drop Sears from consideration. Often they have entry level sales people; you probably want someone more experienced. – wallyk Aug 25 '13 at 2:25
  • Can you read the actual label on the existing air-con unit? It's possible the original unit was replaced with a smaller one, or the original paperwork is wrong. You might actually have a 2t one. – SomeoneSomewhereSupportsMonica May 2 '16 at 13:00

The heat pump can move heat indoors to outdoors ("air condition") as well as from outdoors to indoors (heating). The cooling only unit can only air condition.

If the house already has heating or you rarely need heat, you can save some money by getting a cooling-only unit, and maybe supplement that with portable electric heaters as needed.

As to brand comparisons, I strongly recommend you review the Consumer Reports reader reliability report of air conditioners and heatpumps: that can be done online by paying a fee, or visiting a library.

As for some installers carefully measuring and the others not, the latter could be fine if your dwelling is not especially unique: an experienced installer has run the numbers so many times that they know what the result is. That experience is helped by there being a coarse choice of capacities: 2 ton, 2.5, 3, 3.5, 4, 5, 6, 7.5, 10, 12.5, etc.

On the other hand, not measuring could be a sign of an unknowledgeable installer. Do they also propose a 3.5 ton unit?

As far as questions to ask, I like to elicit being assured that if anything goes wrong for X years, they will fix it for free. If they can say so confidently, that is a very good sign that they don't think anything will go wrong.

It might be useful to ask an installer why they choose 3.5 tons and not 3 or 4. There is a certain degree of assumption about worst case and average case conditions. If the a/c can't quite keep up on the 5 hottest days that is one thing, but if it can't keep up on 30 of them, that is quite a different matter. Likewise, an oversized system can chill the air so much that it doesn't have to run much, making the air stagnant and possibly muggy. Questions asking about how they balance those factors are good for you to understand and for the installer to reflect upon.

  • I updated my post with some more information if it helps. – Xaisoft Aug 25 '13 at 2:21
  • 1
    Thanks for your help. I ended up signing up for consumer reports. I can't find much on ac units. I did read that good man had most repairs or ac and head pumps. I can't find any information on Ameristar which is what one tech wants to install. All I know is that it is a brand from Trane made in China, so I guess it should be called ChinaStar :) – Xaisoft Aug 27 '13 at 14:21

Differences: none and probably made by the same, or comprable, manufacturer. 13 SEER is the lowest efficiency HVAC system a contractor can install. There are much better systems out there that would significantly reduce your electric bill.

2 ton or 3 1/2 ton? there is a nameplate on the outdoor unit that will have a model number. Something like xxx24xxx etc,. the 24 means 24,000 BTU/hr or 2 tons (12,000 BTU/hr per ton).

I have a freind that has a variable speed system the runs on low speed all the time and he has a $90 electric bill, in FLORIDA! Do your homework.

  • My brother lives in Florida and pays ~$60 a month for electricity, I live ~100 mi away still in FL and pay ~$240 a month for electricity. I have a slightly larger house and use gas as well but we average the same number of KWH but I have way higher utility rates. $90 in Florida is relative to a lot of other factors, if you could state what size unit he had and how much we was paying before then their monthly bill might become useful. – Jason Aug 25 '13 at 14:24
  • 13 SEER is the lowest allowed in the US (exception to window units) but is the most common. Energy Star will only certify >= 14 and in 2015, you can't install lower than a 14 SEER in FL and most South Eastern states (acca.org/archives/industry-resources/government-affairs/hot-air/…) – Jason Aug 25 '13 at 14:31

I sell Ameristar and have for several years. Very good equipment almost no warranty work ever needed. A lot depends on your installer and his competence. The problem with both Ameristar and Goodman is that anyone that has a licsence can buy them at the local wholesale shop, that doesn't mean they know what they are doing when it comes to installing them..trust me when I say there is a reason that I get paid 80 bucks an hour to fix those screw ups. Get someone that makes their living in HVAC not a buddy that used to do HVAC or a fresh grad from a trade school or a guy that works as an installer for a plumber that a buddy knows. Be sure your contractor can and does do warranty work on the brand you buy,,,what ever that brand may be.


I have installed Goodman for years with hardly any problems. The warranties are very good (10 year parts and compressor) plus you can purchase a labor warranty. I warranty my labor for a year after installation. Also if you need parts after the manufacturer warranty they are less expensive than most other brands. It does depend on the installer. If Goodman is installed right, you should not have problems.

Not the answer you're looking for? Browse other questions tagged or ask your own question.