Should tenants pay for solar?

[Coco Cook]

I installed a solar system on my single-family home in Southern California.  The payment for the solar system  came out to  about the same or less than my regular electrical bill.  I moved and rented the house out .  The property management company said the tenant should not pay for my solar system .  However I know that their electrical bill is much smaller than it would have been in a non-solar house but I'm paying $116 a month for a solar system that's benefiting them .  Should I have insisted that the tenants pay for the solar? Or  was the property management correct in saying that the solar system was an improvement and they shouldn't have to pay for an improvement?