Sue, I've heard folks tell that it helps to insulate under the floor. But what about insulating down the basement walls to a few feet under grade? That wouldn't take a lot more insulation, and you'd have some more comfortable space in the basement. In summer, I often turn on the furnace fan late in the afternoon when things get rather hot, here north of the southernmost Great Lake (Erie). That blows some rather cool basement air up into the house. We find that in that semi-cool basement in summer the warm air moving down there from outside tends to deposit some moisture and goods made of iron tend to rust. Some papers, etc. tend to mould and there is some on the walls of a finished basement room. Several years ago our local utility added a timer to our water heater that made it run at 2:00 a.m., when there was low demand for power (with an over-ride button that one could push in case of shortage). Plus they added an insulating blanket. When another jurisdiction took over that project, they removed the timers when they made service calls, plus the insulation, when they installed a replacement heater. At least, they were going to, but I told them to leave that blanket right there - which they didn't mind doing. Hope you can make arrangments that keep you and yours as snug as a bug in a rug (or should that be, " ... as snug as bugs in rugs"?). ole joyful P.S. I guess the number of bugs isn't a big deal for you who, like I, live alone. o j

Good luck. I hope you find a solution. I do put one of my two cats downstairs but I physically caught him eating the insulation on multiple occasions so I obviously try not to do it for too long now but now that I am doing renovations upstairs and I am also doing partial renovations downstairs he's going to have to go there more often because I need to put him somewhere and there are other issues with other rooms. I guess I will just have to pull out all the insulation as I cannot do a drop ceiling (you will see in another long post that is one of the things the town has told me will make my basement "finished" and they will re-assess my taxes. I have no idea how much he ate before I realized what he was doing UGGHHH. I took in my ex-husband's cat almost 2 yrs ago when his house was destroyed by fire and the two cats hate each other even though I introduced very slowly and did everything by the book so it makes it more challenging trying to separate them and keep mine out of the basement (my house is NOT big). I guess it will just be easier to take down all the insulation but it's fairly old and nasty too so it won't be a very pleasant task.

Where I am, HD carries the 4' high rolls. However, since you only need a small amount, just use the smaller rolls or batts. Extruded polystyrene (XPS) and expanded polystyrene (EPS) boards would have to be covered with a fire retardant, typically 1/2" gypsum board.

Spray foam is the easiest way to seal rim joist cavities. I've never understood the point of insulating between the basement and the first floor-- it is code required here and no one can tell me why, There's typically little, if any, temperature differential, it's all inside the house's conditioned envelope. Rigid foam on the basement walls would be my second step, with, as Worthy says, the top half being more important than the bottom half-- sealing the rims would be first because that's typically a source of a lot of air infiltration. In a small house it's an easy (and fun) DIY project with the spray kits available at the big box stores.