Target
Basically, Pinkerton is the one you need to influence. But if he doesn’t budge, maybe the town council could pass a local law. Perhaps the renters could use their power as consumers. Encircle your primary target with secondary targets!
Tactics
You decide to begin with a friendly meeting to explain the virtues of energy conservation, its environmental effects, and how it pays off after a year or two. You explain to him how it will make his apartments more attractive to potential renters. Estimate the costs for him, and give him the names of local businesses that could do the job. Ask him to at least give the tenants rental credits for the price of insulating themselves. At the same time you could organize the tenants to request insulation or rent credit. Ask for a response within a week of your meeting.
If he refuses, start publicizing that fact and tell him you intend to do so. Mention him by name, and lament the fact that he’s not willing to do this little bit to save his tenants money. Conduct a survey of the cost of utilities for various apartments, especially energy efficient ones. Compare his apartments to those of the other apartments and publicize it.
If he still refuses, you might try to get the Town Council to pass a local law saying that either: A) all utility bills should be paid by the landlord or B) tenants should get rent credit for any energy-saving investments they make in the apartment. This would actually change the economic relationships between the tenant, the property owner, and the environment!
If that fails and you have to play hardball, leaflet and poster during renting season and tell people not to rent from him. You could also have everyone pay Pinko’s rent in pennies! Check and make sure that isn’t illegal first.