looking for a study on market value of homes after a radiant retro fit installation

I'd say that information is going to be hard to fine...at least if you're in NJ/Eastern PA. Most houses are forced hot air. The few that have a hydronic system do advertise it in the real estate flyers but I don't think it translate into a higher price point. I think a house will be worth more to someone who knows what they are looking at. There isn't enough data to really determine a markert value...I would suspect the value doesn't change much unless you find the right buyer