Ramona and Charles “Hugh’’ Shields were not the least bit reluctant on Monday to open their new house in the tornado zone to a bunch of strangers who had a lot of questions. “I used to live in a house where I had to wear two pairs of socks in the winter to keep my feet warm — not anymore,’’ said Ramona Shields. “This house is nice and warm in the winter, and nice and cool in the summer.’’