There have actually been a couple of great studies of weatherization and health, the best I know of in New Zealand. I think they used a randomized wait list design.
And the RWJ Evidence for Action program just funded a project to evaluate a weatherization initiative in Tennessee: http://www.evidenceforaction.org/health-benefits-low-income-weatherization-evidence-action
One challenge here is getting collaborations between the kinds of people who work on weatherization and the kinds of people who measure health outcomes. They just don't come together all that often to conceptualize rigorous approaches to evaluating health effects.
Nice example!
Maria