Replies

1. 
   FredB | May 08, 2000 04:24am | #1

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   What he is using for the supplies and returns isn't the issue. The issue is what the resulting air circulation is going to be. If he can provide a plan and the numbers showing how the air flow is going to do the job then ok. But, too often dead spots and relative air flows are not considered resulting in cold and hot rooms when everything could have been comfortable. Comfort in this case means the tenants won't be raising the thermostat to get it warm enough in the cold rooms and opening a window to cool it off in the hot rooms.

1. 
   Charles_Moore | May 13, 2000 06:27am | #2

   *The basis approach is very common and usually very effective -- especially for the first floor. Normally the second floor doesn't get the comfort increase the first does -- but it usually doesn't get worse either. Fred is right on with his comments --- think thru what the air is going to want to do at each point and be sure that enough air is available to and wants to go where you want it -- if not find a way to add a pair of supply and return ducts that will do so.

2. 
   David_Henderson | May 13, 2000 06:27am | #3

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   I'm going to install two new gas furnaces in a 75 yr old duplex of mine. (1000sf each apartment)The existing furnace (1) has a shared COLD air return three stud bays wide for the upper and the lower pats. For the new installation for the lower apt., my HVAC man is going to use the existing HOT air supplies as COLD air returns(all on inside walls), adding new HOT air supplies under the windows on outside walls. For the new installation in the upper apt. he is going to block off the lower access to the shared Cold air return and use it for the COLD air return and continue to use the existing HOT air supplies. Does this sound like a viable plan? Thanks for sharing your advice