Dog smell passing through HVAC to second unit.

[Ty Cover]

Hello, I’m looking for ideas to deal with a bad smell coming from my upper unit in a duplex to the lower unit. 

When I purchased the house I did a full rehab and converted the unfinished basement into a two bedroom. The upper unit is 4 bedrooms. There is one HVAC and the intake Is upstairs. 

The tenants in the upper apartment own two dogs. The rent is $2600 and the mortgage is $1650 so i don’t want to evict or be difficult. The lower apartment will rent for $1500. 

The problem is the dog smell coming through the vents and making the lower apartment difficult to rent. I have considered closing the vents and installing mini splits, but I would prefer keeping the costs lower. Do you know a way I can deal with the smell? 

[David Krulac]

Duct cleaning with deodorizing.  But the real solution is separate heat paid for by the tenants, such their is no duct sharing between units. If there is dog odor, there probably is dog hair in the ducts.