Originally Posted by dhartman
As a licensed builder I can say the best idea is going to a 4x4 site and asking advice about your house.
The amount of variables that need to be answered before you can make a decision on this prove this an impossible question to answer without a visit to the house to diagnose the conditions. And no, a crawl space does not necessarily need to be conditioned. Do you want to add that much area to your heat bill?
Call someone in to look at this before you just throw money at it.
You do t have to condition your Crawlspace but if you don't you will have cold floors. If you do heat it and have warm floors you will be much more comfortable. One would be more comfortable in a house with air that 67* and floors that at 67* then a house where the air is 72* and the floors are 61*
You say you are concerned about the added cost of heating your Crawlspace and I would put money on it that anyone who has a properly insulated crawl and heats it does not notice a substantial increase in cost. That being said I would likely pay 20- 25% more for warm floors if that's what it took rather than walk around on freezing floors all day.
Cold feet= cold body