So, a fair price, a fair down payment, terms that are conventional for the type of credit extended, interest isn't pulled out of the air, it reflects risk assumed, but such deals do run around the 7 to 10% realm, you do need to ensure that seller financed usury laws are followed, if any.

Both units have central air and furnace (have to make sure they're separate) water is on one meter.

The triplex was built in 1963 without air conditioning or heating.  

They could tell me this and that needs to be changed or dealt with or else, and if I didn't know any better I would fall for that trap and fork over big money (yup, I sure did fall for the air filter scam).

Here are some facts about the transaction: the seller didn't disclose anything that wasn't working, my agent didn't include the ac in the repair list( on the inspection report it says the power source for forced air does not operate, the cooling system was not operated) and I don't know why.

Air sealing a rental with electric heat is very important as well as efficient light bulbs etc..

Electric baseboard is always 1:1.On top of that the unit provides air conditioning in the summer with a SEER rating of 30, which is more efficient than the through-wall air conditioner it is displacing.

It had central air added and was painted inside, also the kitchen and bath were rehabbed.

The house now has new plumbing, new and updated electrical and new furnace with central air conditioning.  

A hot water tank, furnace, satellite receiver, air conditioning unit, security alarm system or water softener, for example, could be rented by the homeowner.