Wood burning furnace and septic tanks

[Luka Milicevic]

I came across a potential deal on a property that has 2 single family units on about 3 acres.

The one unit doesn't have central air. It has window AC units and a wood burning furnace that is about 2 years old. 

They also share a septic tank and are NOT separately metered for water.

I have no experience with wood burning furnaces and septic tanks. They both scare me if I'm being honest, but it could just be my lack of knowledge on these factors.

Selling for $120k, combined rent of $1.4k/month so just over the 1% rule. I'm not sure if this is enough to compensate for the added expenses that come with a septic tank and possibly having to put in central air.

Thoughts?