I pulled up the floor to the crawl space just in the back part of the house to put black plastic down and insulate it and I found a one foot square hole to the outside and the air coming in is FREEZING. There is a half basement with a small window and another small vent about 7 inches in diameter under another room next to the big freezing one. The house was build in 1900.
Can I seal up that airspace or put insulation over it? It also has a grating outside on the ground and I bet when it is raining that water gets in too.
What are my options? Thank you