cost effective insulation?

Question

Due to rising heat costs, I was looking around for some cost effective insulators for an apartment I'm looking after for a friend.

He suggested we should place 1.5 inch styrofoam on the walls (inner) and then cover it up with dry wall.

It's a large apartment so we'll be covering alot of units so I'm wondering if there are any good cost effective insulators that can be set up to cut down the heating bill?

NOTE - This is in Alberta so we sometimes get cold winters. I usually get my supplies from Totem but I would like to see if anyone has any good ideas on how to do this?

Answer 1

Foam insulation isn't a fire hazard as long as its covered with a non-combustable material. Drywall qualifies. Polyisocyanurate foam board like Thermax has a higher R-factor than stryrofoam. Another material is radiant barrier insulation. Here's an example.
www.insulation4less.com
Hope this was some help.

Answer 2

Styrofoam is a horrible fire hazard. Don't use that.

Pink fiberglass roll insulation is actually pretty reasonable in cost. I'd consider that. There are also insulations made out of treated recycled paper. They might not be too expensive.