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Need advise on replacing our 5 ton air conditioning unit

Posted by myhatt (My Page) on
Thu, Nov 17, 11 at 11:49

I am currently in the market for a new air conditioning unit. The evaporator coil on our existing unit is shot and the cost to replace it on a 9 year old unit doesn't make since.

We have gotten estimates from 5 companies so far and the prices and what they think we need are all over the place. It has been quite an education. What we do now is we want a 16 seer and we know we need 1 additional return.

We have been quoted on Trane, Rheem, and Lennox. I was advised by a friend to look at off brands like American Standard because the parts of all the units are made by Honeywell anyway. Is there any truth to that?

We also need some type of special filter or light to help with my son's allergies. The recomendations on these differ as well. One suggested a MicroPowerguard, another the Trane Clean Effects then there are the uv lights, standard, included in some quotes, or the ultra max.

Sorry for the long post, I am hoping someone can shed some light on all of our options.


Follow-Up Postings:

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RE: Need advise on replacing our 5 ton air conditioning unit

Myhatt

What type of furnace do you have now?

Is it var speed model?

If not, you should just stick with a basic 13 SEER model with matching evap coil.

Am Standard is not an off brand. It is the sister company to Trane.

You might want to consider an EAC like the CleanEffects as well as UV lights to deter mold. Not a fan of that idea though mainly because of ozone produced and the cleaning/maintenance schedule associated with EACs.

UV lights possibly and then a good pleated box filter would be my preference. I think you have to weigh this carefully against your son's allergies.

IMO


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RE: Need advise on replacing our 5 ton air conditioning unit

Than you.

Our existing unit is a Goodman with a really low seer, can't remember exactly.

We looked at the 13 seer as well and the price difference was very small so we decided to go with the 16 seer unit.

Your opinion on the CleanEffects is the same as 2 of the contractors and it does make since. We had the ozone cleaners from Sharper Image and those things were a bear to clean. That is why we are leaning toward the Micro Power Guard, it has filters that are replaced every couple of months depending on how dirty they are.

Is there any brand you would recommend? Lennox and Trane seem to be the most expensive.

What are your thoughts on the dual compressor? We live in hot S. Florida and it seems like a pretty good idea.

Thanks again.


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RE: Need advise-missing the Point.

Myhatt

Sorry but you are missing the point.

Do you have air handler or a furnace?

You can not pair a 16 SEER AC condenser with a non var speed air handler or furnace.

IMO


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Need Advise

Sorry, we have an air compressor not a furnace.

Thoughts on the dual compressor? The idea of staring out at 2.5 tons only going up to 5 when needed seems like a pretty good idea.

Thanks


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RE: Need advise on replacing our 5 ton air conditioning unit

Stil missing the point.

Your location?

An air compressor? Your terminology is wrong.

You must have either an inside air handler or furnace that is paired with an outside unit either HP or AC known as a condenser.

If your inside unit is not var speed, then you can not go with a high SEER outside condenser.

If someone is telling you otherwise, they are simply mistaken.

If going with high eff outside unit, then inside unit will also have to be replaced.

Can't say any more on the subject.

Good Luck!


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revised

I meant air handler not compressor. We live in S.Florid and we are replacing the entire systems, both the air handler and outside condenser.

Sorry to frustrate you with my lack on knowledge, that is why I came to this site, to hopefully learn something and get some good advise.


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RE: Need advise on replacing our 5 ton air conditioning unit

I have not been checking recently, but as of a couple of years ago, there was little objective data that indicated that UV lights could do much of anything to help with allergies. I think the return on expensive filters is similar. That would be when added to a system that is functioning well in a home that is kept clean and outside air infiltration is controlled.

Of course "allergies" does not really tell much of the story. The most important thing in dealing with allergies is to identify the allergens. If you don't know that, you are stabbing in the dark.

Humidity control is going to be very important in S. Florida. Another issue is duct placement and leakage. If the ducts are outside of the house envelope (crawl space or attic) and leak, you are blowing out conditioned air through supply duct leaks causing a partial vacuum in the house. That sucks in hot humid air through any leaks cut in the house envelope. Hot humid air then hits cool surfaces and causes condensation and fungus growth.

I have not looked at this for a while, but check it out:

My House is Killing Me! The Home Guide For Families with Allergies and Asthma, by Jeffrey C. May, Johns Hopkins
University Press, 2001.

For building and AC issues in the hot humid South, FL universities have some good resources. So does www.buildingscience.com . If you are going to look at one thing at that site, make it this: http://www.buildingscience.com/documents/insights/bsi-015-top-ten-dumb-things-to-do-in-the-south/?searchterm=top ten


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RE: Need advise on replacing our 5 ton air conditioning unit

Replacing your interior air handler with a variable speed blower will do a lot for humidity control. You can also look into the concept of 'Dehumidify on Demand' which runs the system at low fan speed for maximum humidity extraction without lowering the temperature too much. This usually comes with a smarter thermostat that measures the humidity and 'communicates' with the air handler to set the fan speed.

The idea of a 2-stage compressor is good. But you need to know how the different manufacturer's 'stage' their units. They are NOT always 50/50 but can be 60/40 or 70/30.

I would be surprised if there was little price difference between a 13SEER single-stage unit and a 16SEER 2-stage unit, unless the power company is giving you a discount.


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RE: Need advise on replacing our 5 ton air conditioning unit

For a good filter/UV light, take a look at Ultravation. You can jump on their website.

For better humidity control, and increased blower run time (not at full blast) and therefore increased whole house air filtration, it may be worth it to you to get a higher SEER system with a modulating air handler and 2 stage compressor. But be aware that these are not "just a little bit" more than an 13 SEER entry level system. But they do offer increased comfort. The equipment cost on a system like this will easily be double or more than double that of entry level. (your dealers installation labor won't change all that much, so the overall bid would not be double.)

Personally, unless you won't miss the money, a mid-tier system with 15-16 SEER matchup will get you the biggest bang for the buck. It is true that you should look at any programs your state or power company offers to make sure you get what qualifies.

Previous posters are correct about SEER. The SEER is only true when looked at the WHOLE SYSTEM. An AC unit can say it is rated 16 SEER. But your overall system will obtain the SEER of the "weakest link". So if this is not matched with particular furnace/air handler and coil, the system will not be a 16 SEER system. So ask your dealers to put the AHRI matchup on their quote, and verify the SEER ratings yourself.


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RE: Need advise

Thank you all for the excellent information. We are definitely going with the 16 SEER system it's just a matter of what brand.
Yes, FPL does give great rebates on high efficient
models so to us, the price difference between the 13 SEER and 16 SEER 2 stage unit was not enough to go with the lower SEER.

As for the filtration system it looks like ultravation and micro powerguard work the same way. They both have filters with high MERV ratings, 11 and 13. Adding a good UV light would be the best right? So many choices....


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RE: Need advise on replacing our 5 ton air conditioning unit

heat pump??
or electric strip for heat?
heat pumps provide both cooling and heating from the
condensing unit. in cooling it is a/c in heating it reverses action and provides heat. electric strip is
used for emergency heat.
unless a homeowner has gas, heat pumps are what we recommend in my hot humid climate.

its very expensive to heat with electricity,
so heat pump is a better option.

I'd forgo the uv light for mastic seal of all ducts,
plenum and equipment to plenum connections. mastic
seal supply boxes to ceilings and all return air.
if you keep the debris out of the ducts and equipment
then you have no need to zap stuff in the air steam.
a well sealed system and a 4" pleated media filter is
a better investment.
this is usually what we do for homeowner complaints of
allergies..seal the system. mastic seal will last for 30 years with no service. uv lights need to be changed yearly

are you sure you need 5 tons?
even with staged systems you can be so oversized that
your unit has short run times, resulting in lessened humidity removal.

all brand names of a/c have sister brands
trand/american standard etc
same features different exteriors & pricing.

just as sealing ductleakage is a good investment
so is air sealing the house.
florida solar energy center has good info for your area.
along with buildingscience.com you should check out the unbiased information they offer.

best of luck.


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