Common complaint 1st floor cool 2nd floor hot
Can you guys give me a bit more insight on trouble shooting a system when customer complaint is 1st floor cools well but 2nd floor is hot during cooling season.
Poor insulation, no attic ventilation, poor duct work, or lack there of for 2nd floor. Unbalanced system. (assume an older house?)
Is it one unit cooling both floors? If so may need a zoning dampers if duct work is properly done.
New homes. Actually quite common. Running into a few customers with new homes and same complaint.
Yes one unit houses. Id say ~2500 sq ft homes with 3 1/2 ton units.
I would like to offer some suggestions that will make a significant difference in the 2nd floor cooling
I've seen them with a smaller tonnage upstairs.
Seal duckwork, insulate attic to R-60 and consider radiant barrier.
Economy - Quality - Speed <---- pick two
It's been controlled with zoning for years. In the summer more air goes upstairs. In the winter less air goes upstairs. I've seen some of the new big homes having 2 systems to avoid the issue.
I would ask if they tried closing a few registers down stairs
Need to add a location to your profile as that makes a difference too.
Dennis keyed in on the obvious, make the house more energy efficient. I tell people to spend money on low-e windows and insulation vs me redoing the duct work and oversizing the system.
You could add some returns in the upstairs to pull the heat out.
Easiest solution: cut first floor dampers down to force more air to second floor(air takes the path of least resistance). Better solution: Arzel zone system.
Best solution is 2 systems. Here in south Louisiana you almost have to have 2 units on a multi level home.
A large part of my business is custom homes constructed by builders as the direction of the homeowner.
In the past however we did new construction of tract housing.
There is some unwritten law that must say only 6 inch flex is to be used no matter how long the run or how high the load.
As a general practice we do not use flex duct unless there is no alternative, yes it costs more but the customer would rather have the system work properly and they're willing to pay for it.
“You don't get paid for the hour. You get paid for the value you bring to the hour.” Jim Rohn
I definitely agree that the use of flex duct is my least favorite alternative. It does install quick, and can be done cheaper, but I think the customer gets so much more
if they invest in metal duct, which is the lifeblood of the system.
Flex is ok in smaller systems and IF done correctly. I have one I need to go redo. Single runs and apparently he didn't know you could cut the flex. There is a 25' bag on each run not hung!
turn on blower 24/7
Originally Posted by Bobe5531
The jist of your problem is this.
Originally Posted by Bobe5531
Air stratification: The air in two story homes will naturally want to layer as colder air on bottom with warmer air on top. Where do we always put the t-stat... First floor, the cold floor, unless you also have a basement which will suffer the opposite problem and be too cold.
Improper duct work: Shoddy install work aside the duct needs to be properly sized and balanced, this typically doesn't happen. The next part is returns, lots of homes in the south(where I'm at) have a central return, if a door is closed that room no longer has proper return air and it pressurizes to the point that the only supply air entering is due to leaks in the room. Think of a paper bag that you are blowing air into, once it fills up it's hard to blow any more air into it but if you poke a big hole into it you blow air and change over the air easily. Ever had a customer complain about a bedroom that has no return? I have a lot of times.
"Fixes" that often fail:
-Booster fans, these are not going to help.
-Adding a stat upstairs that is wired in parallel with the main floor stat, this may get the unit to cool the 2nd floor but now you are over conditioning the first floor big time.
-throwing some dampers in on the existing duct work, if the proper homework isn't done here you will create a new problem when you close down the first floor by building up Total External Static Pressure past the rating of the blower motor.
-run the blower continuously, this would have to run all the time to have any affect and would drive up energy consumption and often only helps a couple degrees and many times you still have a 6*+ difference.
The best fix is a total house assessment to determine the best solution to offer your customer, once you have it all figured put you can then look at the existing system see what works with the solution, maybe you can just balance the system and better protect the upstairs envelope from heat gain but maybe you just have to start all over with a properly sized unit, zone system and ductwork or a system upstairs and downstairs.