Tenant who smokes

[Pete Wobus]

I became a landlord for the first time earlier this year and made a stupid mistake: I rented my house to two adult smokers and did nott include a "no smoking" clause in the lease. The renters are otherwise very nice people who pay on time but insist on smoking but only in the basement. Because there is no door separating the basement from the rest of the house I think damage to the rest of the house, which includes new (fairly high-end) carpet and paint, is inevitable.

I'm considering asking them to purchase and use an air filter machine as a partial solution. Their incentive would be to avoid losing some or all of their security deposit to pay to restore the house back to it's original condition.

Can I have some opinions/feedback from you folks please?

I should mention that this family is from overseas and probably do not fully understand the implications of cigarette smoke damage and their security deposit. Thank you all in advance!