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A/C experts please???
lindalecowboy
Member Posts: 1,909 ✭✭✭✭✭
Is there a sensible limit you should observe when installing a new system? 14 seer 18 seer??? I don't know what all that means just know more is better but is there a point where you're paying for more than it makes sense to use?? 2,400 sq ft house, 12' ceilings in main part, single unit??
size, brand, seer recommendations please??
size, brand, seer recommendations please??
Comments
Note: The variable speed indoor unit, or VS, will dramatically reduce the humidity level in your home allowing a higher temp setpoint on your thermostat. Thus, lowering your electric bill even beyond the equipment replacement.
I have seen bills drop 50% by installing the 14 SEER systems.
16 and 19 SEER units take a lot longer to realize payback.
Also, make sure the refrigerant is 410A (Puron) as R-22 is quickly phasing out.
I like Rudd and Goodman units. Trane and Lennox is high around here.
Compare warranties too. If you go at least 14 SEER, you should get a factory equipment warranty of 10 years for no extra cost.
Size of the unit depends where you live.
In Texas, you need 4 tons on new construction with lots of insulation and 5 tons on an older home.
I figure 500-600 sq/ft per ton and never have problems.
A load calculation is good, but mostly is innaccurate here and causes undersizing. Depends on who is doing it. Your conractor should have the experience to know this answer immediatly.
Please get at least 3 bids. No, really!
Can you do dual zone ?
No, wished I could, when I've had split systems, it always works best. This is an 11 year old home, fairly well insulated but old style.
A/C calucs are very regional. I would ask at least 3 companies in for a estimate. See what their numbers are for BTU (or Tons).
The only problem I foresee with a variable speed unit is that some units have the fan running all the time. It makes for a short life for the motor.
Also make sure the filter is easy to get too (it has to be changed up to 6 times a year. Also that the filter is a common size. I went with a 4" thick filter (more surface area = less filter changes).
Margaret Thatcher
"There are three kinds of lies: lies, damned lies and statistics."
Mark Twain
As always, appreciate the good advice from those who know. Not my area of expertise.
We find that over 90% of the duct systems are undersized and ALL of them leak air. It doesn't make sense to invest big bucks for a high efficiency system and not fix areas that will cost you from now on because the problems weren't taken care of. I would venture to say that you would be way ahead by choosing a 13 SEER system and tighten up the duct system. By performing a load calculation, you would also be able to see how adding additional insulation in the attic would affect your system selection and sizing. Adding insulation is one of the fastest paybacks available.
Our company has blower door testing which gives us the tightness of the home and the duct system. We also have a system called AeroSeal which seals the inside of the ductwork without having to manually go to each duct and seal it, and then refasten the insulation.
Let me suggest some websites to visit which will help you make a wise direction to head. www.nationalcomfortinstitute.com; www.aeroseal.com; www.comfortinstitute.com; www.acca.org;
One of the posters said to get 3 estimates. I would say get as many as you need to feel comfortable with your choice---that might be 1 or it might be 10. If someone comes out and spends 15 minutes and gives you a price on the back of a business card, I would steer clear. Warranties are also important. We provide a 100% money-back guarantee for the first year that the system is installed. If the customer is not satisfied, and we can't get them satisfied, we remove the system and give them their money back. There has to be a professional job done to be able to offer that warranty. In addition, I would look closely at getting a 5-year parts and labor warranty at the minimum.
Good luck.
Also the unit is VERY quiet. It is right off our deck in the back of the house and when it flips on, you can talk at a normal level and don't even notice it. This is a big factor in the cheaper units, the outside piece is very loud.
Not a whole lot of price difference either.
That's why I suggested the 14.
I find that most systems are undersized here too, especially the upstairs units.
All that new fangled testing is fine. If you want to pay for it. Either your home is new or has had an A/C system in it. If it is newer what size did you have? If it is an older one, what size? Was it efficient? What were your bills? So in a nutshell, were you happy with the costs? A good reputuable A/C company will automatically come in and evaluate your needs. Three or four of them should have similar stories on your estimates. When you get done... do a heatpump.
Yep, listen to the slumloard that leaves his tennents without heat for 3 days in the dead of winter "because it costs more to have a guy come out on the weekend".
And when we did it, we were told to wait - suffer thru 3 months of higher bills for code to change in January. Our 16.x unit cost less than a 14.something unit would have by waiting that 3 months...
quote:Originally posted by Barzillia
Can you do dual zone ?No, wished I could, when I've had split systems, it always works best. This is an 11 year old home, fairly well insulated but old style.You can still use a single unit and create multiple zones using multiple thermostats, a zone controller, and switching type ducts. At some point I plan to install this type of zoning in my home to improve selective cooling and heating of my mancave! Honeywell makes this type of equipment and I've bought the thermostats and controller, but still need to buy the ducts.
If you can't feel the music; it's only pink noise!
Mike
What if that "new fangled testing" could save you 30%-50% on your heating and cooling bills? Most contractors don't go the extra steps to reduce the energy usage that needs to be done. The money you save on energy usage belongs to you and is not taxable again. If you have to make more money to pay higher energy bills, then you pay the additional taxes on that money. You referred to the size that they have already, and if they have stayed cool, then that is basically the size they need to go with. What if the home had additional insulation installed in the attic, new windows installed, and other "tightning up" of the home with caulking and other weather stripping? With those things being done, the heating and cooling system are now probably oversized.
I can't tell you how many customers we've had over the years that said if they needed a 3-ton system, then put in a 4-ton because they want it to cool down the house in a hurry or want it real cold. When a system is oversized, it doesn't run enough to remove the moisture in the house, and the system short-cycles, making the unit draw more amperage as it starts up so frequently. This is also harder on the compressor. Oversizing also doesn't allow the unit to reach it's peak efficiency by having a longer run time.
Someone mentioned automatic zoning. That is a really nice way to control the temperatures in your home. Google Arzel Zoning for their system. It is easy to install in an existing duct system and they have a really quality product.
There is a lot consider when making a decision that most don't do the research that could save them a substantial amount of money in the future.
quote:Originally posted by lindalecowboy
quote:Originally posted by Barzillia
Can you do dual zone ?No, wished I could, when I've had split systems, it always works best. This is an 11 year old home, fairly well insulated but old style.You can still use a single unit and create multiple zones using multiple thermostats, a zone controller, and switching type ducts. At some point I plan to install this type of zoning in my home to improve selective cooling and heating of my mancave! Honeywell makes this type of equipment and I've bought the thermostats and controller, but still need to buy the ducts.
That's pretty cool (no pun intended) I didn't know that was available in residential cooling. I know about those thermostatic air "flow" controllers for commercial/buildings, but guess I should look at that for the house??
thanks
For instance where I live is 7.5 cents per Kilowatt/Hour. Second cheapest in the nation.
For me to put in an 18 SEER unit would not make any sense. Because for the unit to pay off in saved energy vs. the cost of more efficient units would take many, many years.
Now if I lived in Hawaii where the power rates are 29 cents per Kilowatt/Hour (highest in the U.S.), the pay off for a 18 SEER vs. a 14 SEER would make more sense.
So you see how it's very regional. An intelligent local contractor, that can do the calucs, is your best friend. Matching the right equipment with the right duct, can make for an efficient system that will not cost you an arm and a leg. And also be as efficient to operate as possible.
The air handlers have a number on the nameplate. It is the amount of static air pressure that the unit can produce. From that number you have to subtract the resistance of every register, the filter, and every foot of duct that the air has to travel. Now you know the amount of air that you have for each room. Then you take the type of construction into consideration, whether the room has exterior walls, window sizing and type, whether the room has any exterior walls that are south facing, and lastly the size of the room in cubic feet.
So you see it ain't all about driving up, squinting at the house and saying, "Yep, that take about a 4 ton unit".
Margaret Thatcher
"There are three kinds of lies: lies, damned lies and statistics."
Mark Twain
My old unit is just doing OK so sizing is not necessarily a good job and is aging fast. I'm not sure what a Miller system is but I've never heard of it and believe it to be a "builders grade" unit and hope to upgrade to a much more energy efficient unit.
IF I use gas heat in the system it doesn't make any sense to go with "heat pump" does it?? Isn't that just for all electric units??
Once again, this group has amazing talents and information. thanks guys, I appreciate all the great advice.
My old unit is just doing OK so sizing is not necessarily a good job and is aging fast. I'm not sure what a Miller system is but I've never heard of it and believe it to be a "builders grade" unit and hope to upgrade to a much more energy efficient unit.
IF I use gas heat in the system it doesn't make any sense to go with "heat pump" does it?? Isn't that just for all electric units??
You are correct.
Not really. You can have a dual fuel unit. It runs the heat pump until it can no longer keep up, or if the temp drops below a certain set point and then the heat pump will drop out and the gas furnace will kick in. They are really nice for places that are almost too cold for heat pumps but not really cold enough for only gas heat.
Mike
If yer north a ways, you can go dual fuel. Got to factor in the costs for your area.
A well-matched 13 SEER condenser can produce a 15 SEER system rating.
This usually includes a slightly oversized coil and variable speed.
Variable speed has issues with some older ductwork systems, but not all.
We figure each SEER at $400.
If you get two extra SEER through well-matched components, the extra efficiency can appear to get you the variable speed for free. Variable speed as a stand-alone option might cost $700, with a payback of two or three years through electrical savings.
With top-line equipment, like Carrier, the highest SEER condenser, the 24ANA1 series, one usually sees a system rating of 18 or so.
Figuring one gets four SEER more over a typical 14 SEER system, the extra efficiency is "worth" $1600, and the guv'mt tax credit is $1500. That makes the extra $2500 one may pay up front appear to make the numbers make sense. This is assuming you want to buy extra efficiency up front.
The credit requires 16 SEER and 13 EER, two numbers not met by Carrier's 17 SEER condenser, hence the 21 SEER example.
It is easier to achieve HP rebate numbers of 15 SEER, 12.5 EER, and 8.5 HSPF.
Combining a heat pump with gas backup, a hybrid, or dual fuel system, will be the best option in the long run, whether or not it makes the rebate.
Remember that salespeople and installers are not your tax advisers. Promises of $1500 rebates are moot if the equipment doesn't make the numbers as described by the tax code and the American Refrigeration Institute [ARI].
Quality equipment will come with a 10 year parts warranty even in 13 SEER.