I have a 1920's craftsman style house in Washington state with a kitchen extension built over a crawl space. In the winter the kitchen is quite cold. I am about to re-do the floors in the kitchen and change them from a laminate to oak. In addition to ensuring the crawl space is insulated, is there a product or anything else I can lay underneath the hardwood to provide additional heat rentention that is cost effective. The kitchen is by far the coolest room in the house (in the winter) and the only one over a crawl space.