Home A/C Vent Temp Issue?

Question

Had a house inspection on my house that I am selling. All vents registered a temp of around 53 degrees, except for the 2 vents in the master which reported temps of 62.

The duct work for the master goes comes down through the ceiling, our house is two stories and there is a large attic area above our master that these ducts run through. Additionally, these are probably the two longest runs from the main downstairs unit. My thoughts are this is why the temp is different. The inspector thought it might be a crimped duct run, but I'm not sure. Anyone have any thoughts on what else might cause this?

Answer 1

Your getting too much heat gained from the attic its running through.

More insulation on the duct may be the answer.

Hopefully the duct itself is sealed air tight, if not that would need to be done and then re insulating.

Or if it's flexible duct it might be better to rerun it with new duct.

Either way I would have a professional look at it and and give you tour options.They will know if something is not right on the sizing and whatnot.

Answer 2

You would have to get up there to inspect the duct work.(early in the morning).There might be a very obvious solution that you can fix yourself.I have ran many "upstairs running warm"calls in the heat of summer when only one unit was cooling the entire house.You have to go through every check one at a time.It's sometimes time consuming.

An expansion valve not feeding properly (coil not cold over it's entire surface)will also cause this.Dirty filter,coil, refrigerant charge,a duct leaking air,or an under sized unit will also do this.Good luck and remember to check what you can yourself before calling for service.

Answer 3

trace those ducts back to the plenum you will see they are not at the end of plenum or worse there tapped right off the evap coil no static pressure nothing to do with the system if your getting 53 out of some alot of stupid installers out there they do it all the time no concept on a correctly installed system its all in the plenum and duct work