[MN Renovator]

I can relate to jeff5may on post #5

"They call the local utility company and schedule an energy audit to find out where their home is on the energy-efficiency scale. What they find is confusing as heck to them."

Did this, didn't receive anything on a scale basis other than CFM.
My auditor tried to tell me that my furnace was 60% efficient which isn't true.
He argued that ACH is pointless and to ignore it.
He then took the CFM converted it to ACH and told me that I had enough natural ACH to where if I didn't seal my house that I could skip additional ventilation.
When I asked him about my "60% efficient furnace" he recommended to get it checked annually and wait until it failed a heat exchanger inspection.

He also said that my 2x4 16" on center construction wrapped in 3/4 of XPS is a "R19 wall" because "that's code for the 1980's. ...sure an R13 batt plus R3.75 of XPS makes an R19 wall.

He seemed to be all over the idea of getting a water heater blanket like it would save the world and 'pay for itself in under a year'. ..sure the 4 therms a month it used was $2.60 at the time and 12 months would be $31.20. Quite certain I'm not going to save that much in a year by buying a $20 water heater blanket, I use some of that hot water, its not all going to the basement. Water heater insulation is a good idea and is fairly easy but he made it sound like the single most important thing to do.

I asked him about sealing attic facing top plates, got no info there about attic insulation other than to seal plumbing and electrical penetrations. I'm glad I read about it here and saw S-F's pictures.

It is found during the audit that the home is "not too shabby for the neighborhood".
Mine actually thought the 2x4 design with 3/4" rigid wrap was a good idea and is 'plenty enough insulation for a house'.

"The envelope has been sealed up to "acceptable" levels and has been insulated to "above average" value."

Apparently 1500 CFM is 'plenty good', 'don't worry about it', and 'if you seal much more you'll need a ventilation system.' worthy discussion points.

"Not quite energy star, but better than most "affordable" site-built homes are being constructed today in the region."

Mine had huge thermal bypasses into the attic. I found roughly 500 sq inches or 3.5 sq ft of what were essentially holes in the attic that I've sealed up.

"During the conclusion of the audit, the homeowner sits down at the kitchen table and is given what seems to be a really expensive sales pitch. The auditor recommends to just gut the whole HVAC system and put in something new. A quick tour of the new systems on the market is given, with "good, better, best" systems of increasing estimated cost, naming major components but not much detail. A "top ten" list of local contractors is left with the report, and the auditor makes a hasty exit."

My auditor gave me the cheap fixes. Used estimates and payback periods and basically said to not do anything with only 7" of cellulose in the attic, not do anything about 1500 CFM at 50 pascals, don't consider adding additional insulation if you replace the siding, be sure to put a continuous(2 speed) bath fan in the house if you seal up the place.

I asked him about passive house insulation or at least super insulating my place and he talked about how it won't work out well for me without more thermal mass.

He left and I feel that I would have been better off with two box fans sealed in a window and renting a thermal imaging camera from Home Depot. Oddly enough, I'm looking to do that again after I have insulated, air sealed, and did everything else that I'm planning to do to this place since some of the images that I really wanted of my house during the audit, I did not get.

If you insulate well enough, I do agree with Daox though. You'll save tons more for the same amount of money by insulating and air sealing than you will on replacing the equipment. I'll save more than 26.6% of my energy with less than 1/4 the amount of a $8000 upgrade to a 96.2% efficient furnace and a 16 SEER AC. I'm thinking I'm already better off than 26.6% and I don't even have the $300 of cellulose plus blower cost in my attic yet. $140 of spray and rigid foam seems to have made a huge difference once applied to the right places.

What would you guys recommend as a starting point, assuming the homeowner can swing a couple thousand dollars or so today if it will reduce their utility bill? Bang for the buck would be to go into the attic and seal all of the wall top plates, electrical penetrations(use UL 1479 and UL 2079 rated caulking for junction boxes), and plumbing penetrations. Seal any second story or story+half knee wall holes. Pull the window trim and seal all of those gaps. Seal electrical and switch plates with the foam inserts you can get at your hardware store. Put on the thicker version of the water heater blanket. Seal the sill plates in the basement that face outside. Be sure the gaskets are good on all doors(top, bottom, and sides), check the windows too. Put on window shrink plastic, especially in the winter, but for windows you don't open in the summer, leave it on in the summer too.

After the easy bang for the buck stuff is done, return to the attic and get R60 in your attic if you are in a climate zone like mine or at the very least what the DOE recommends for ceiling/attic insulation. I was surprised that I could get just over 1000 pounds of cellulose for $250 after tax (add another $50 for blower) and will probably put me between R60-R75 from my original 7". I'm looking at about $500 with everything said and DIY done with my house and that feels super cheap to me. The next project is to add 4" of polyiso or XPS under the siding when I do DIY siding replacement on my house. That is more work and I'm less familiar, but I'll start with the easiest side first and then maybe do a side each summer until its done. A heating load calculation suggests I'm cutting my peak load by about 2.5 times and the heating bills should be reduced by even more than that. I'm planning to get solar shade screen in the summer to block out sunlight on the west side to cut the AC costs.

All of this will cost less than the $8000($6000 after government and utility rebates) for what amounts to minimal mechanical efficiency improvements in comparison to real envelope improvements. Oddly enough this makes my home even more of a candidate for ultra efficient mini-split equipment. I'm actually looking at heating and cooling my entire home to my satisfaction with one 12k mini-split heat pump and using the gas furnace on the coldest days as a backup to the mini-split or use its blower or maybe a little gas when I need a more even temperature when I have guests over. I'm particularly looking at benefits such as the super high SEER, dehumidification dry mode, local heating/cooling when I want to close the door and chill in one room on the computer or in a book all day, and long cycle benefits when cooling too.