What do I need to know about insulation?

I bought my house in June. My inspector told me that my back room (not an add-on, but most likely was a porch that was enclosed) doesn’t have insulation under it and would be getting cold in the winter. We hit the 30s last night, and I could definitely confirm that was true. I originally thought I wouldn’t be using the room much, but I’m in there a lot (I put my desk and bookshelves there).

I saw that the hardware store has insulation on sale this week, and figured I’d ask to find out what I need to know. I haven’t had the opportunity yet to get intimate with my crawl space, and this seemed as good a time as any.

So… insulation types I should look at? Specific sizes I should be aware of? Things/tools/hardware I need to install it? General websites that are good go-tos for stuff like this?

You need to know the space under the floor before you condider how to insulate.

Maybe you need to insulate the walls around the crawlspace - maybe you need to apply it directly to the underside of the subfloor. maybe you can spray the crawlspace spray in insulation, maybe your only option is to redo your floors or add a carpet.

How do I go about determining this?

insulating crawlspace walls is not good because you will still loose heat to earth or crawlspace floor.

putting insulation between the floor joists is good.

That’s what I was planning on. I know that insulation batts should go in loosely (don’t jam them in), so how do you attach them? Are there specific straps you’d staple across the joists to hold them in? And where can I go to determine what R-value I need?

One method I heard of is to hold the insulation up between the joists with chicken wire stapled to the joists

You can buy pre-formed wire hangers wherever you buy your insulation.
How to insulate a floor.