3 ton vs 4 ton - same value $$ ?

[NewHvacGuy]

Should the price/value for a 3 ton vs 3.5 ton vs 4 ton AC be the same or little difference?

[beenthere]

There isn't that much of a price difference between 1/2 ton sizes on the equipment.

Doubtful that if you have a 3 ton system now, that your duct work can handle a 4 ton.

[rohalon]

If you go the the hardware store to buy a cordless drill, which is going to cost more, the 12 volt or 18 volt?

If you are trying to ask about different contractors quoteing similar prices for different size equipment, there is more to what they charge to install than just what it costs them to purchase the equipment.

[darctangent]

Learn to utilize Manual J load calc for sizing a system for a house and then verify that the system can handle the necessary Air flow for the tonage with one of two methods-
1) Static Pressure test (super easy if you have the right gear)
2) Temperature rise method.(again , easy stuff with the right tool.)

[NewHvacGuy]

So, sounds like there shoud be some $$ difference for 3 ton vs 4 ton AC (even though not much). Thanks for all the information.

[dan sw fl]

So, sounds like there shoud be some $$ difference for 3 ton vs 4 ton AC (even though not much).

As for ANY product, the so-called value is greater with a larger quantity.
A 5-ton unit is SIGNIFICANTLY cheaper than a 2-Ton unit
on a per ton basis.

The overall system installed cost does not have as dramatic a difference as the equipment cost ratio.

HOWEVER, proper equipment sizing and the associated resultant performance shall be selected per ACCA Manuals J, D and S.

[pstu]

NewHvacGuy, are you asking about a replacement or new construction? The larger sizes may demand ductwork if a replacement, while the smaller size may not. Keep in mind a salesman will probably fib and say existing ducts "will be OK" if that helps him make a sale -- he may actually believe it, or may just be using his brand of sales tactics. If you are up-sizing it probably will not be true.

Those uncertainties make it hard to answer your question accurately.

Hope this helps -- Pstu

[zzonko]

:mad: :mad: :mad:


NewHvacGuy, are you asking about a replacement or new construction? The larger sizes may demand ductwork if a replacement, while the smaller size may not. Keep in mind a salesman will probably fib and say existing ducts "will be OK" if that helps him make a sale -- he may actually believe it, or may just be using his brand of sales tactics. If you are up-sizing it probably will not be true.

Those uncertainties make it hard to answer your question accurately.

Hope this helps -- Pstu

In my opinion, I think that you should not be giving advice to other homeowners or anybody for that matter on this forum. Not all salesmen fib and this is our livlihood. Just learn here and use it to your benefit. You ARE NOT in the trade

[darctangent]

So, sounds like there shoud be some $$ difference for 3 ton vs 4 ton AC (even though not much). Thanks for all the information.

hmmm.. maybe I'm barking up the wrong tree, but I don't think so...

If you're trying to decide whether to install a 3 vs 4 ton system on a house(do I smell homeowner?) based on price you are REALLY, REALLY missing the boat.

a Whole House Manual J is the SHALLOW end of the pool for getting your system sized correctly. I wonder how many other short cuts you're thinking about?
Since you've taken the time to come here why not find out what you're missing from a technical standpoint. I just hope you are getting some brand I've never heard of, or would ever think of selling to a customer, because at the very least It won't last as long as it should. The options get worse from there, and quickly.


P.S.- just remember, if it's not working right, you might try adding more 'freon'

[darctangent]

Sorry I shouldn't be so harsh, but the content of my message is still valid- ask around, others will tell you much the same thing.

[t527ed]

So, sounds like there shoud be some $$ difference for 3 ton vs 4 ton AC (even though not much). Thanks for all the information.


but installing the right size...............priceless!:D :D

[dan sw fl]

hmmm.. maybe I'm barking up the wrong tree, but I don't think so...

a Whole House Manual J is the SHALLOW end of the pool for getting your system sized correctly.

Whole House calculation with appropriate building envelope details and duct loss factor is fine for a bid by a mechanical contractor. However, installation and air distribution require a room-by-room assessment and detailed duct design.

[pstu]

I owe you an apology Zzonko. I was in a hurry to get a warning to the homeowner, focusing too much on what might go wrong, focusing hardly at all on my words which were a slander on the whole sales profession. My words were hyperbole, I should have thought up a different way to say a warning.

In the age-old discontent beween sales people and engineers, I tend to side with the engineers even though I am not one. The difference between pre-sales promises and after-sales reality is one of the battlegrounds. That is fair to say don't you think? I do think it would be a disservice not to warn a prospective buyer of bigger equipment, that this is an engineered application not an appliance.

Regards -- Pstu

[darctangent]

Whole House calculation with appropriate building envelope details and duct loss factor is fine for a bid by a mechanical contractor. However, installation and air distribution require a room-by-room assessment and detailed duct design.

My larger point was that a technician or home owner that is trying to decide what size unit to put in a existing space based on price is going about it all wrong. I'd rather use rules of thumb over some home-owner's opinion that is driven by price. In other words, that's just plain stupid.

BTW, I'm not entirely sure I understood the motivation behind your comment, but let me say this- a room by room isn't at all out of line if one suspects that the Duct design (or rather the lack thereof) is preventing key areas of the house from being cooled/heated properly. Believe me, I'm no purist, but when the situation warrants it, I'd rather know what kind of mess I'm walking into before I put my name on a install.

I recently did a sales call on a new(2 year old) house in my area and after doing a quick check of airflow on the second floor, I told him that I wanted to some more checking of duct work because I was sure that I wasn't going to be able to cool the upstairs adequately. That would really suck, since that was his main objective in getting AC in the first place.

I haven't been able to get him to agree to more poking around yet. I don't know why- he agreed with my reasoning, I told him that there would be no charge for the workup of what he really needed to do to make the system run right. I think he's afraid of the cost of my bid.

[NewHvacGuy]

Sorry to generate such a heated conversation here. I think I got the point. Thanks!