DIY Duct Sealing, Pls Evaluate
About 2 years ago I improved my ducting by tying it down, tightening joints then sealing with mastic and metallic tape.
Last week, a duct test revealed ~14% leakage (just under our Code/Reqs). The local vendor can install new ducting that targets 9% or the top-line at 6%. They are going to run numbers for me on costs/benefits.
1) Would you consider 14% a poor/adequate/good job for a DIYer?
I'm wondering if there are points of leakage out of my control, such as within the gas-pack or the sheet metal interfaces between the roof.
2) If I slightly increase tonnage (+0.5) on new HVAC, I may replace it all anyway (vs. just increasing return and a few new supply lines). Outside of that decision, would you think it's worth upgrading ducting to gain a 6% improvement just on its own? It's probably going to run a couple/few thousand.
Opinions? As always, thank you for volunteering your time.
Duct Details: I'm in Central CA, have 20yr old grey R4 flex duct in the attic, with a 14" return feeding about 10 supply vents to condition ~1150sqft. The original Carrier 48NLT gas-pack on the roof is still in place (replacing soon with a 14seer).