Special Holiday Offer2 Gifts for $16It’s Like Getting One Free!
Should under the house be insulated?
Most State Codes require it now. Fiberglass in the joists is better than nothing.
If it's not a vented crawl space, insulating the walls with a rigid foam board or a 'curtain wall' (fiberglass insulation wrapped in a thick poly) are good options.
Spray foam is available, i'm just not a fan.