Two-Stage A/C Systems Save Money, Energy

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Subject: article

You mean time to draw moist air into the furnace and to condense the moisture ie not evaporate it. Evaporation occurs in the closed loop of the coolant coil in the furnace where water vapor condenses from a gas to a liquid on its outer service but in the evaporator unit the refrigerant is evaporated from a liquid to a gas.


Subject: Dual stage review

My home has three 5 ton dual stage Trane systems.... Absolutely love it. The house maintains a steady temperature throughout and my bill is actually lower then my old single 5 ton system in old house... Often Its so quite that I can't tell the systems iare on !!!!


Subject: Dual Stage - Trane systems

did you use Trane service guys or your own HVAC? what is the seer rating on the one you chose? did you have to replace furnace as well?


Subject: Replacement whole Ac system

1500 sq foot living area need a 12 vent 3.5 ton system installed with duct sanitize. And a additional return. What is the price on a good quality system.??

Bob Smith

Subject: Replacing condensing unit, AC

air handler is 7 yrs. old. and of the high efficiency type. single speed fan. Condensing unit is 21 yrs. old working but will need to be replaced sometime soon. would a 2 stage unit be compatible?


Subject: Compatability

Probably not, since almost all of your newer system use R-410 refrigerant and your evaporator system is probably R-22. The fed gov is making R-22 very very expensive to try and force those with older systems to purchase the newer ones that use more enviro friendly refrigerants. I personally upgraded in 2010 to an American Standard Platinum series system that's been pretty good so far. Multi speed air handler and twin compressor condenser with a SEER rating of 20. My cooling bill dropped considerably since summers here in texas can be brutal. 2011 saw us with 70+ days in a row of 100 degree temps and my highest bill then was $228 and that's maintains 73 degrees round the clock. My only complaint has been with part availability with AS. The air handler fan motor went out last Oct and since it must be programmed it had to come from the factory in order to maintain my warranty. Took two weeks almost and I was beyond mad at the situation. And now in the last week my system took a lightning strike shorting out the low stage compressor. However, I have the system running in high stage only temporarily until my replacement arrives, so it's not a total loss. All in all its been a good system. I would check to see who your preferred AC man is s certified dealer with before deciding on anything, because warranties are getting more and more difficult to administer and the average AC guy may not be able to provide u with free service should he not be a certified dealer.


Subject: Compatibility

Depends on if you have a variable speed furnace, Even if you do its really not ideal to do so., reason being is you wont meet the SEER ratings your trying to achieve

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what should you pay.  You pay what you can afford.  1100sqft unit requires a min. of a two ton unit.  prices range from 2100-2900 depending upon the seers of the system.  13 seer is the min. the law requires  and for your situation with 1100 sqft.  do not worry about the seers as long as it is to code.  the bigger the house the more seers for economy.  1100 sqft is at the border line for a two ton system.  It is more important to have your new system balance, there is where you get the economy on your electric bill and gas.  Bryant, lenox, ruud and carrier are the brands you should stay with.All have the same basic factory warrantee and will last you longer than you expect as long as you maintain it with regular check ups twice a year once in the spring and then in the fall.

raymond gonzalez
koolray heating and air
? offers a nice sizing chart for HVAC capacitors and furnace capacitors. Most of the capacitors I've looked at are $5 to $15 dollars, so a little less than Home Depot and Lowes.


Replacement is really easy, but be sure to watch a youtube video on how to replace it like this one:


Stay safe and hire a professional if you feel unsure about doing it yourself!

The only thing of importance, is the hvac professional you choose to use. Alot of manufacturer's pieces are built relatively the same, and will last about the same amount of time. The thing that matters most is what you can not compare between companies, and that is the installation. Purchasing a system is not like purchasing a car, where no matter where you buy it, they are all the same. Each installation is different, and usually what you are paying for is the level of expertise, and quality of the installation, the company who will actual give you the warranty, and the comfort that you will receive. Manufacturers warranties disappear every day. They always have a loophole where they can get out of paying, but your local dealer wants to keep you happy for future work, and to protect his reputation in the communiy. Look up 4 year old Nordyne and Goodman warranty problems. Choose the HVAC professional first. It will cost you the least in the long run. I have had to totally redo plenty of installations that were just performed because of an uncomfortable customer, and a system that keeps breaking down. The equipment is only as good as it's installation, and over 70% are not installed correctly.
I think maybe you are confusing SEER, which is an efficiency-related rating (higher SEER means more effective use of the electric power used to compress the gas), and TONS rating, which is a measure of the total cooling power of the system. (Tons used to mean how many tons per hour of ice was used in evaporative cooling building systems - a Refrigeration or Cooling Ton equals 12,000 Btu/Hour of energy exchange. A BTU, which is another antique measure but still used, is the energy needed to change the temperature of a pound of water one degree fahrenheit. Unfortunately, because of varying humidity and evaporation, this is not readily related to house air heating or cooling without a lot of assumptions and some computations. Relating this to today's world - the Manuals BayAreaAc referred to account for all these energy conversions and determine an estimated cooling (or heating) requirement for your specific house. The type of construction, solar exposure, general climatic conditions such as average temperatures, humidity, and hottest and coldest normal ambient temperatures and desired inside temperture are all taken into account in the more sophisticated versions of the analysis, so there is no "standard", though a rough old rule of thumb was about 1 ton of cooling per 500SF of house. Obviously, this was a WAG only because it did not account for insulation, type of roofing, whether you live in Alaska or Miami, etc. The ACCA manuals do a very simplified form of evaluation to arrive at a "design", which generally will be adequate. OF course, highly precise calculations are not really needed because A/C units generally come in even ton ratings - so if you are at say 2.6 ton requirement you will be getting a 3-ton unit anyway. SEER ratings are not a direct measure of efficiency, but the relative difference between ratings gives you good idea of the unit's relative efficency in using electricity - so a 16 SEER should be about 19% more efficient (so roughly comparable lower electricity bill) than a comparably sized 13 SEER unit. 13 SEER is the lowest efficiency currently allowed to be built for general use, 19 SEER is about the highest efficiency made by pretty much all manufacturers, and about 25 SEER is the highest rated though very pricey shelf-item units, though special construction custom units can reach about 30 SEER. Note however, like any government sponsored rating, much of it is hooey when you get down to it - for instance, SEER ratings are figured based on 80 degree inside air temp and 82 degrees outside, when that is far from the normal case of mid to low seventies inside and high eighties or above outdoors. This makes the absolute SEER rating meaningless, but relative numbers still have meaning in comparing units. Note these efficiency ratings are for conventional air conditoners and heat pumps working in ambient air conditions. Ground sourced Geothermal or lake/river exchange cooling units, though initially more expensive in most cases, can greatly exceed the air-exchange unit efficiencies because they are exchanging heat with cold natural water rather than with a high-temperature outside air, and instead of continually compressing a gas are just circulating cold water. I worked on one geothermal cooling project which had almost infinite efficiency, which of course makes no sense - but the only power was for sensors and a control valve as the water flow was single-pass under gravity flow, so no power was used to circulate the water.