Raised rents, landscaping, added fence and deck, major utility upgrades (water/sewer), converted sunroom from uninsulated/unfinished to true insulated 3-season room with new roof, adding updated fixtures and finishes, paint.

That doesnt count having to upgrade the disconnect which is potentially thousands more if you dont have the juice to handle a condenser.   

I purchased two properties (one for 50k and the other for 62k) that have roughly 30-40k in equity through upgrades and appreciation.

or Add more upgrades to further increase value?

The HOA fees cover any exterior costs like roofing so I only have to be prepared to cover issues inside the suite - although there usually are special levies every year that they charge a few hundred bucks for to upgrade/maintain various issues in the complex.

There will be a lot of repairs needed as they haven’t done any rehabs or upgrades since they’ve bought them about 7 years ago.

If possible please share costs this hvac upgrade may incur

Im fortunate enough my fathers a plumber and with my experience and guys who work with me we handled every aspect, used no sub contractors except to upgrade service to breaker panel.

If the property is buy and hold the good upgrades will mean less repair and maintenance in the future.

Exterior upgrades include: new roof, siding, screens, landscaping, paint.