Upstairs AC unit can't keep up on these hot days

Mac5005 said:
without all the data, my initial bet is on minimal insulation on ductwork and air handler in unconditioned attic, on a system that was likely not pressure tested and or actually sealed.

Meaning so much loss thru the ducts themselves makes the cooling ineffective upstairs. That loss being from air leakage and minimal insulation.

TLDR: donā€™t put air handler and ductwork in unconditioned attic space. Envelope of the living space or in conditioned portion of attic space.
Click to expand...

I have only a single story ranch but it is built on a slab so the ductwork is in the attic which gets full sun most of the day. The system is many decades old so I had to split open the insulation wraps and tape seal many joints to eliminate losses. I did a thermal scan with a borrowed infrared camera one winter to identify where I had leaks. I also bought a pile of the newer duct insulation with the radiant barrier to shield the ducts and started putting radiant barrier in the attic to cut down on thermal soaking. Then for two underperforming areas of the house I spliced in duct booster fans to help even out the airflow. Overall I have the house fat more even and comfortable than it was years ago.

When I did an addition on the house years ago I did the manual J calcs to figure out where the house was when I bought it (no wall insulation, barely anything in the attic) and where it was at the time (R-20 walls, R-30 in half the attic, R-60 the other half) and found that my system was actually a lot larger than it needed to be for how much better the house was. Unfortunately this does not translate to all address of the house being comfortable so I had to do the aforementioned fixtures in the attic to get it better.
 
awheelterd said:
His brother built his house šŸ˜‚
Click to expand...


Be Quiet Season 2 GIF by Martin
 
Back
Top