This will be as much reduction as retrofitting about 200 homes, without any of the social benefit. Not to dismiss their work, but puts things in perspective.
Perhaps reduced cost to the homeowners for heating and cooling their homes with a reduction in pollution due to lower energy production.
Hmm, perhaps. Though the first part are just private benefits to the homeowners (which of course, should go into the cost-benefit analysis), and the latter is basically the same kind of benefit that the proposed ocean seeding has.
I have no data on which method is best here, I was just confused by 'social benefit'.