Who pays for air duct cleaning?

[Alex Shipp]

Have tenants who claim they have breathing problems and requested the air ducts to be cleaned. I looked it up and there is no scientific evidence that cleaning air ducts improves air quality according to the EPA.

Air ducts is kind of in the grey area of whether it's regular maintenance or not. Should I say this isn't regular maintenance and refuse to pay for it, split the cost 50/50, or pay the whole cost?

Part of me thinks, I should pay for the whole cost just to maintain a good tenant relations. 

What would you do?

[Alex Shipp]

Update: I paid to have all air ducts cleaned in the entire house. It ended up costing $350 after negotiating down from $550. 

My tenants were complaining a little bit too much and decided it wasn't worth the risk of losing them as my tenants when the lease was up.