I received a new brand new AC unit from my father who bought it for his place but it was too small. Anyway I was looking at replacing the old one I have. I live in Las Vegas and any energy savings would be great since I hit $370 during summer last year on my 1551 sq ft , 1 story place, ouch! I'm wondering if it would work , if it would be worth installing, and what it would run me. I'm planning on having the house for at least a few more years.

Details:

Existing unit: I couldn't find much info.
Made by Payne
Model - 565bJ048
Found this spec sheet www.xpedio.carrier.com/idc/groups/public/documents/techlit/pds565b.14.6p.pdf
Not sure how to read the tables but it appears to be
Cooling capacity: 45,500
System Watts: 5447
Seer: 8.5
This is a ground mounted unit.

New unit:
Goodman
Cooling Efficiency: 12 SEER
Cooling Capacity: 30000 BTUs
Cooling Capacity: 2.5 Tons
Voltage: 208/230V (1 Phase)
Compressor Type: Reciprocal
Suction Line Size: 3/4 inches
Liquid Line Size: 3/8 inches

The new unit is obviously small but I'm not sure I need a large unit. No large ceilings, single story.

Maybe I should get a manual J done but if I can't afford a new unit right now anyway so no point if this new unit won't work.

Any help is greatly appreciated. There are so many AC people here in Vegas its a bit overwhelming so I want to be as informed as possible.

 

With out the manual J you no nothing. Get it done!

 

What can I expect it to cost approx?

 

id say around $150.00. It should take a couple of hours.

 

That 12SEER 2.5-Ton unit should cool 1551-sf.
I don't know where you live, but with 8-foot ceilings,you can usually: reduce air infiltration, do some duct system work & weatherize your home to get below the load calc that unit would handle.

Since it is a free unit, I'd spend my money on making it operate as efficient as possible.

When you do the other things above, it may end up being a bit over sized. It is those other things, plus a proper install, that will save you the most money.

In the USA, there is money available for weatherization.

It is a good idea to do a manual J load calc. - Darrell U

 

You really need to do a calculation but for a wild guess I would say that where you are a four ton unit would not be that far off.
If your unit is working properly you could take a reasonable guess as to how it matches your home by how it behaves.

If you find that it cycles off in the hottest weather then it might be slightly oversize.
If it runs continuously and just holds its own in the hottest weather then it could be sized properly.
If you find that what you have is a reasonable size for your house downsizing to a smaller unit will not save you anything.

Like I said, this is just speculation so if you want an accurate assessment do a load calculation.
Here is one place you can buy this program and it only costs $50.00 for a single use.