New System Needed

[beberly1]

Hi everybody. I need to replace our existing, officially dead A/C system before Summer gets serious here in Orlando. I've gotten 3 quotes & am down to just a couple questions. Hopefully you guys can help.

1) Size. House is 1345 sg ft, in high heat & humidity Florida. I cannot tell the size of the existing unit & have been told it's 3 ton or 2.5 depending on who I talk to. I have been quoted on both 3 ton & 2.5 ton. The guy suggesting the 2.5 says longer cycles will control humidity better & the guys suggesting 3 says it will get on top of the heat better in broiling July. In all cases a 3 ton variable speed air handler would be used. Suggestions?

2) Trane vs. Carrier. The 3 possible systems are: 1)Trane XR13 3 ton with 410 refrigerant & 4TEE3F37B air handler. 2) Carrier 25HCA36 3 ton with FV4BNF003 air handler. 3) Carrier 25HCA330A003 2.5 ton with FV4BNF003 air handler. I've been told by the Trane guy that his is a much better unit. I've been told by the Carrier guy that the entry level Trane was not designed for the higher pressures of 410 & is a potential leaker. Carrier also said their air handler is much tighter & will not draw hot air from the garage where its located.

If it was your house, would you go Trane or Carrier & 3 ton or 2.5?

Thanks in advance for the advice.

Confused in Florida.

[<kjpro]

A proper &#39;load calculation&#39; will solve this battle.

Equipment bashers are NOT the people you want to deal with. Get one that understands that a proper installation is the key, to the longevity of ANY system.

Niether, I would install the brand I sell everyday. :-)

You&#39;re welcome.

[Noon-Air]

First find a contractor that will *DO* a room-by-room heat load/loss analisys on your home. You could need anywhere from 2 tons to 5 tons. Unless you do the calculations, your only guessing. Try here for a competent tech in your area

Did any of these guys offer any actual proof of the supposed shortcomings of their competitors equipment?? Did any of these folks suggest that their systems would be elegible for the frderal income tax credit?? Did any of them offer a 10 year parts and labor extended warranty?? Did any of them offer an ARI certificate of efficiency?? Did any of these guys actually *DO* anything besides bash the other brands??

I wouldn&#39;t have a Carrier in my home. Trane is a good choice, However I prefer the brand that I carry.

[udarrell]

Orlando Florida, Summer Outdoor Design conditions: 93-drybulb,

76-wetbulb a 17 degree drop gets around 45% relative humidity. You have around 2600 hours of A/C runtime a cooling season, that is close to the highest runtime hours which is a little south of you in Florida at 2800 runtime hours a cooling season.

Therefore, getting the heatgain as low as possible before you do anything else, followed by a thorough testing of the ductwork system for leaks & proper sizing will be critical to achieve the most efficient operation of a high SEER system. Do some reading of my page below - with many more linked info pages on it

"After" you do everything you can to your home to reduce the heat/humidity-gain, then have an accurate no fudge manual J done, a Manual D, & a manual S should all be done.

If you want efficiency & a low humidity level, "Never oversize the A/C equipment."

Then learn everything you can before making a decision on the contractor & the equipment you go with. A proper install is the key factor in whether you get the performance you paid for!

[Bob_Loblaw]

udarrell wrote

How do you determine the R value of insulated walls of a home unless you open them up? Same goes for windows. How many of us can accuratley determine the R value of a window or door? I suspect most guess, which brings into question the reliability of a manual J. Ask 3 contractors to do a manual J and you&#39;ll get 4 different results. It&#39;s pretty hard to get a truly accurate heat loss/ cooling load calc in anything other than a new home with known R values. I&#39;m not saying you shouldn&#39;t do one, but I question the true value of one on an older home with so many unknown variables. It&#39;ll get you in the ballpark, but 3 different, competent contractors doing a manual J could come up with 3 different suggestions for needed equipment.

[Bubba]

My Turn! :-)

1) Get 10 more quotes. Line them all up for the same day and space them out 1 hr apart. Hey, we quote em for free so why not find the lowest price? 2) Dont worry about the size. You&#39;re like everyone else. When its 95-100 degrees out you want the house cooled down quick. Get a 5 ton and stop worrying about it. 3) Buy a Goodman. They are cheaper so you can get a higher efficiency unit for less money. 4) Dont worry about a Trane or Carrier. Its going to rust out in Florida faster anyways so get the cheap unit. 5) Get an R-22 unit. The refrigerant is way less in cost than the R-410a. Who cares if production of 22 will cease soon. 6) A roll of duct tape will seal all the air gaps you want so dont worry about a unit in the garage. 7) When you&#39;re all finished, sell the house because it will be worth more with a new HVAC system installed. Your Welcome. Bubba

[gofish]

seriously, you dont know how to perform this procedure?

seriously, you dont know?

wrong. no guess work involved. extrapolation yes, guess work no.

I agree. the untrained find it pretty hard indeed.

More importantly, how many contractors can read the engineering data sheets to determine sensible capacity at design temps....