Why is the heating system not sufficient ?

Hot water, gas, heat, trash, and snow removal included.

You can also use PEX pipe which has excellent resistance to freeze damage, and you add a 1/2" think layer reflectix foil insulation along the outside wall (which reflects 90% of radiant building heat back toward the house (but no good for reducing conductive heat loss -that is handled by insulation).  

I am working on a flip, where the numbers are a little tight, and I will do a really great job to be able to list at the top of what the area will let me.I need to provide the house with new heating and cooling.What would you do?

Keep dropping heat!

Tenants pay electric and heat and the property has a private well for water.I would self manage.Garbage(dumpster on site) and city sewer is $395/mo averageThere has been zero vacancy in the last 10 years.I would offer $150,000 cash sourced from a private money lender at a zero interest rate.

I always use Andy Semones, with Metro Air and Heat, for years on all my rentals and flips here in Winston. 

We added washer/dryer connections to all units and ductless min split heat pumps.

Water source and septic can be built if there is no public water and sewer.Sometimes it so rural you need propane tanks and to supply energy and heat..

Very easy to rent year-round to long-term tenants.Features:* 2 separate electric meters ( Tenants pay electric)* Landlord avg' water & sewer - $68 + $75.Unit A: 2bed/1bath, 660 Heated SqFt, currently rented for only $500 to the same long term tenants.Unit B: 2bed/1bath, 660 Heated SqFt, currently rented for only $550 to the same long term tenants."