Being able to offset my carbon footprint gives me the warm fuzzes inside.

There are a number of requirements that they're pretty particular about:Hard-wired smokes in common areasSecond means of egress for all unitsSelf-closing door hingesPeep hole in each apartment entry doorAll units in good condition (walls, tile, etc. in good shape)Smoke detectors and carbon monoxide detectors as necessaryExit signs (I think)Adequate lighting in common areasThose are just a few off the top of my head.

The real benefits are tax arbitrage and the potential for conservation/carbon benefits. 

Construction standards call for a 1-hour firebreak, if you want a pet door then just understand the risk: carbon monoxide leaking into the house.Attic - another one most buyers don’t get into themselves, but we’ll throw stuff out there anyway•⁠Obviously we look for moisture damage, but there’s a big difference between damage and staining.

@Jonathan YehNew furnace is between $6000-$8000plus...Fire protection which includes;Fire supression between the unitsFire alarms and carbon monxide detectorsEgressed windowsMaking sure electric is to code.

Also get you should get your blood tested for carbon monoxide. if it's forced hot air and you smell gas in the whole house it could be flue gas in vents. 

I went to see the property again and the repairs aren’t that bad...it’s hand rail to the basement, smoke and carbon monoxide detectors, chip paint in the back and front, garbage in the basement and back yard, broken tiles in the bathroom, ceiling repair in kitchen and and rear porch, fix concrete in back yard and some minor stuff.

I have a flip on the market in Denver metro that we've done a foundation repair using Carbon Armor.

Kevin Carbon has a meetup he puts on the events thread.Check his last posting of this one and maybe connect with him @Orion McCabe-Gouldhttps://www.biggerpockets.com/forums/589/topics/272972-best-wa-markets-for-buy-and-hold?

I think it is about $40 for the deluxe package, that includes multiple copies with carbons of every form you could ever need.