Tenant want to install washer and dryer

[Leonardo A.]

Hello everyone, here is the situation, I own a duplex in nj  and my first floor tenant ask me if he can install a washer and dryer in the bsmt, he will buy it and install it, his leased is almost up. How much should I charge him for using the bsmt and having the washer and dryer there, he is a good tenant always pay on time and take care of the property, I was thinking charging him $50 extra, what do you think?