Looking on the Hydrotherm website, they are referring to a R180C and mentioning the date of 1990 concerning some type of upgrades. My guess is pre-1990. If you have the time, you might check out their site and contact info.
They also had one episode where they had an electrical panel hidden in a closet. They cut through the back of the closet and flipped the panel around out into a hallway. Only problem is they then concealed it with a huge picture!! Really disappointed with the "House Detective".
Sure, thats mild. I've got a house I'm in process remodeling and have already found 5 such nests in the walls. I still have two rooms to gut so I'm sure I will probably find at least one more. I think they moved on after I had put on vinyl siding over the old siding 10-12 years ago. Ruined their entry points. The one in the attic must be at least two foot in diameter. DM
I only joined to gain access to the monthly real estate publication. To advertise in it the local paper who prints it is in cahoots with the local board and you have to be a member to advertise. Once I get some good volume built up and my name is well known in this area, I'm out of there! It's less than $200 a year. Dave