Each tenant pays their own electric, so I have been upgrading each electrical panel and putting HVAC units in each unit, this saves me about $20,000 a year in utilities.

That's why I put together a panel of property analyzers in the market, boots on the ground and they know the neighborhoods street by street and have their pulse on the market.I agree that random OOS investing where the investor is trying to do all the research and estimating on the numbers is SUPER dangerous. 

How many Amps is the main panel?

Here are some that I'm aware of:- Galvanized pipes - typically 40-50 useful life, could rust from the inside out, could get eventual pipe failure- Zinsco or Fed Pacific electric panels w/ aluminum wiring that could be a major fire hazard- Wiring in general (e.g. knob and tube)- Asbestos in the walls- Lead paint- Heating system - boiler?

Add on potential electrical main panel upgrades to handle the increased load (assuming no gas service, they'll be cooking and heating with electricity in the ADU), along with drawing and permit fees and you're maybe another $5k. 

You also haven't accounted for capital expenses, vacancies, maintenance, or the solar panel payment in your cash flow calculation.

I am currently in a project making my fathers house ready to sell , 2000 sq ft house , 14 replacement windows , paint . 10 pre hung 6 panel doors , some framing lumber , 10 sheets of drywall some plumbing supplies and misc things and I am in close to $10K . ( NO LABOR MATERIALS ONLY )I havent done Kitchen , flooring , 2 bathrooms , or exterior needs paint and touch ups . .  

If there’s any beadboard/paneling on walls, think about removing that too.

My journey into real estate investing started in August 2023 when I joined the "Homeschooled by Tarek" program, led by Tarek El Moussa himself and his amazing panel of coaches! 

Always count for extra cost, only challenges were just unexpected things coming up such as mold in the attic , broken furnace, and updating a panel.