What do i do now???

[scrap15]

I just bought a home near Sacramento, CA and the compressor valve has gone out. I had a specialist come out and he noted that the unit is totally undersized (3.5 ton on a 2600 sq/ft home)to begin with, and since it is the original (20 years old) i should definitely upgrade to a 5 ton. The home had 200 sq/ft addition after construction. So a 3.5 ton will not be able to keep up with the 100 degree summer heat that is common to this area in the summer. However, he said that there are some major issues that would come along with this newer size: all the attic ducts would need to be replaced with larger ones, and the sheet rock in the downstairs would need to be torn out in order to accomodate the larger ducts. The home does have an attic fan, a whole house fan, and screens on the windows facing the sun, and a patio cover over the whole bottom level of the house.
But here is the problem, he said it would take about $XXXXX to do the job right. And all i have is about $XXXXX to put towards this issue. What can i do? With this amount of money to get the greatest return in cooling of the home?

[lolson]

i have came across your situation numerous times and i dont have any answers for you other than have it done wright the first time.
i cant count how many customers i walked away from because or under sized units and/or undersized duct work that customers didnt wont to pay for, but to do it wright and keep your unit operating for year and efficient it costs money.
dont be a fool and get suckered into getting another contractor that will say the things you wont to hear, like the duct sized ok, or will just replace your condenser. because it will cost you more for repeated service and repairs.

the customers that i walked away from as mentioned always call me back to fix there a/c that has been installed by another contractor (i wonder why the other contractor cant fix it:rolleyes:) and the only thing i can tell them is i tryed to tell you it will not work properly the way it is.

[Gunnery Sergeant Hartman]

Put yor $5000 down and finance the rest...

[bmathews]

I haven't seen the job, but the cost is a bit high to reduct a house and add a 5 ton. If that is the cost of the demo and repair then maybe. I would get a few quotes with different scenarios for repair. Get creative and look outside the box, we get a lot of work that way. But upgrading duct system should be a part of the quote. You might look at using 2 smaller units to accomplish the same task. Without looking at it, it might be less demo on your house. The existing ductwork might be able to accomodate the 2 smaller systems with minimal repairs. It will definitely be more than you want to spend, but will probably be less than quoted for sheetrock demo. I wouldn't call out a company that does service only, get ahold of a company that specializes in new construction, they are usually a little better at this sort of thing. Most service guys only have seen the finished product, not the product all along the way. No offense to you service guys, but its the truth.

[dcmcm5]

How do you know it is undersized? It may be the ductwork not sized correctly or leaking too much, or the unit not charged correctly, or the airflow not distributed correctly. 2600 sf is certainly not too large for a 3.5 unit, depending on several factors. In fact, I have seen 2.5 ton units on houses that size in the hot humid South. Have someone size the unit based on Manual J, select the equipment from Manual S, size the ductwork to Manual D, select the registers based on Manual T, and commission the system to balance the airflow and obtain the proper charge. Only until you do all that will you have a system that is done "by the book" and then if it does not provide adequate cooling can you claim it is undersized. Guessing and poor installation is typical and why there are so many problems. Even when a Manual J load calculation is performed, a sorry installation or a poor duct design and air balance problem can create problems even if the unit is the correct size. Get the full deck of cards and then you can play the game.

[elkhvac]

Did your contractor do a Manual J and Manual D to determine the correct size needed, or did he use a "rule of thumb"? Most "Rules of thumb" will over size systems. Make sure the system and ductwork are sized properly before you drop big money.

[arc8]

Scrap,
Unless you get the Heat load analysis like the last two said, they could be like most of my competitors; they just don't know much about installing the right way.

[Jabarco]

But here is the problem, he said it would take about $20,000 to do the job right. And all i have is about $5000 to put towards this issue. What can i do? With this amount of money to get the greatest return in cooling of the home?.

In your situation, $5000 should be pletty enough to replace the outdoor unit plus install two or three additional window units to help you and your 3½ ton unit get through those 100°F summer days. Otherwise, a $20,000 second mortgage ought to do it.

Hey, I can't help it if they didn't charge you enough!

[skippedover]

The gentelmen who suggested the ACCA manuals be used for sizing the project are 100% on the mark. We also deal with a lot of improperly sized systems but if I were ever going to specify a system that's 1.5-tons larger than the existing job, I'd better be able to supply the written calculations showing how I arrived at that number. Of course, sizing the equipment is only part of the job. The number of supply and return outlets, the size of the outlets and size of the trunk all have to be sized appropriately for the size of the equipment and that's just the beginning. Thoroughly sealing the ducts, sealing the boots to the ceiling, properly insulating both the supply and return are all aspects of professionally designed and installed job. Using 2-stage equipment would give the best comfort for all weather and yes, I agree that a 5-ton system with all of the above attributes would easily cost $XXXXX or more in our market in the Northeast. I'm just having a hard time swallowing the 5-ton estimate. If I were you, I'd demand to see the calculations that can substantiate whatever size equipment whatever company you select to do the job. If they can't supply the documentation, you shouldn't be dealing with them.