Duct sizing is a critical issue, and existing duct systems, especially older heating ducts, are rarely even close to adequately sized for the new equipment.
We are planning to retrofit or existing system with an infinity gas furnace, infinity A/C unit and new coil in our forced air home that is from the 1930's. My question is: in general do most homes have adequate size ducts to handle such a retrofit or is duct size a major issue. Since my contractor did not spend too much time checking out the duct sizes in our house, I assumed that duct size was in general was not much of an issue--- now I am concerned Worried in Washington dc.Thanks for your reply and sorry for any double posts.
Last edited by ron3637; 11-10-2007 at 09:58 AM. Reason: clarification
Duct sizing is a critical issue, and existing duct systems, especially older heating ducts, are rarely even close to adequately sized for the new equipment.
Other than replacing the ducts what can be done to correct for there size. Also is a static pressure test difficult to do? thanks
If nothing can be done what is the difference? What would you recommend if the test comes back negative? thanks?
Something can always be done about it.
The question is how much will it cost.
Some times its a simple fix, and some times its not.
Get your ducts tested/checked first.
Sometimes bigger ducts is the answer. Sometimes low loss fittings can provide enough improvement.
We do load calculations, most existing units in my area are too big. The ducts may be too small for your existing system, but if you install a smaller system, the ducts may now be adequate.
But if you don't test the ducts before the changeout, you are really screwed if you find out they are too small after the changeout. Then you have to do the whole thing over again.
Remember, Air Conditioning begins with AIR.
"Originally Posted by ron3637
Other than replacing the ducts what can be done to correct for there size.
Nothing really."
Quote:
Also is a static pressure test difficult to do? thanks
It's easy for any professional.
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Your comment above lead me to believe that you were stating ducts need to be replaced,sorry for my mistake.
And yes some of what I suggested is adding new ducts and fitting ,just not wholesale replacement of an existing duct system,to solve a static issue.
If it's anything like my house (built before A/C was invented) then the duct size is adequate for heating, but not for A/C.
You better get a straight awnser from your contractor. The infinity system as you know monitors many things like refrigerant pressure,and static pressure.
If your ducts are undersized you will get constant false alarms. Make sure that a manual J and or all proper load calcs are done to your home.This will determine the proper size unit for your home, that way you will know if ducts need repalcing.If your ducts are original since 1930's crap I missed that yeah I think they may need replacing!
WARNING:IF YOU DON'T KNOW THEN DON'T DO, SO THOSE WHO KNOW WHAT YOU DIDN'T KNOW DON'T END UP UNDOING WHAT YOU DID SO IT COULD GET DONE RIGHT!
If the the current old system I have, which I am replacing due to its age, does a good job of heating in the winter and cooling in the summer with the current ducts in the house, why would the same ducts be a potential problem for a carrier infinity system. All responses are appreciaed especially carrier experts. Thanks all for the help and input. ron
If the the current old system I have, which I am replacing due to its age, does a good job of heating in the winter and cooling in the summer with the current ducts in the house, why would the same ducts be a potential problem for a carrier infinity system. All responses are appreciaed especially carrier experts. Thanks all for the help and input. ron