Rant: I quit using plastic sheeting on my Duke City attic reno and my energy bill dropped
Everyone in the ABQ DIY groups swears you have to wrap the whole attic in plastic before you blow in insulation, so I did it on my last house in the Heights. This time on my place near Eubank I skipped the plastic and just air sealed the top plates with caulk and foam. My PNM bill went from $180 to $140 the next month, same summer temps. The plastic was trapping moisture against the drywall and I never noticed because we are so dry here. Anyone else skip the vapor barrier and get better results, or did I just get lucky with a mild July?
The part about the plastic trapping moisture against the drywall is what got me. I used to be all in on wrapping everything, did it on two rentals down in the South Valley, and both of them had that funky smell up in the attic by the next spring. Thought it was just old wood or something. Then a guy at the supply house told me the plastic makes a little greenhouse up there and our dry air means the moisture never gets a chance to dry out. Now I just foam the top plates and around any penetrations and call it done. Your bill drop sounds about right, sealing the leaks is where the real savings come from, not the wrap.