I'm going to be replacing the wall coverings In my home from paneling (with some weird fiberboard behind it) to drywall. It turns out that there is no insulation in the walls right now so I plan on insulating before the drywall goes up. Would it be worth my time/energy/money to fur the walls out to put r19/21 in instead of r13/15? Any thoughts would be appreciated.

Why would you bother wasting your money on R13? To be able to redo your walls with anything but R19 or R21 is unthinkable. Think of just how much more cozy your home will be with the extra insulation. Think of how much money you will be saving on your cooling and heating bills! The answer is LOTS OF MONEY. You could take an all expenses paid cruise to Mars on the money you'll save. If you live where it does not get hot or cold then the R13 is okay... but I don't know anywhere in this country where we haven't had extreme weather.


The fact you had nothing between the weird fiberboard wall and the outside tells me that you have been happily giving lots of money to your local utility company for the privilege of being uninformed. (Watch out once the insulation is in place that you don't get a postcard from them whining why you haven't been paying such high bills lately as they will miss your money). While you're on your insulation adding binge, may I suggest you also add some insulation to your attic as a heck of a lot of heat in the winter literally goes up and out the ceiling as well as the walls themselves.

Why would you bother wasting your money on R13? To be able to redo your walls with anything but R19 or R21 is unthinkable.
Wow.

Hi there Erich,

Depending on your locale, R-13 can be more than sufficient. You'll not have to spend sleepless nights worried over that squandered trip to Mars and your neighbors will not be preparing a lynching party because you singlehandedly caused the extinction of the Amazonian left-handed tree frog with you wasteful use of energy.

If you decide to go the route of R-13, then you can still make in impact on efficiency by attacking common trouble points in your house, like exterior door seals and sashes, windows attic/crawl spaces, etc. The majority of wasted energy in regards to your heating and cooling is not through your walls, but the path of least resistance which is your windows(glass is a very poor insulator ;)) and seals throughout the house. Upgrading windows is usually first on the list.

If you plan to upgrade to a higher R insulation, then you'll want to fir your walls an additional 2" and if you have any doors or windows, create some sill & jamb extensions for those as well. Don't forget to move any receptical boxes you have installed. They sell extensions for them, but they're flimsy and 2" is a lot to ask of them.

Thanks,
Json

Thanks Json,

I guess I should have mentioned that I live in what the NFL announcers affectionately call "the frozen tundra"... Wisconsin. Ive used some insulation calculators that figure in efficiency of heating and cooling and R13 seems to be the consensus, but I'm guessing they don't take into consideration that adding 2" is an option for most people. When I bought the house there were already Low E windows installed (very poorly, the type that fit into existing frames) This spring I plan to re-side the building, reset all of the windows and replace the doors, so I'm hoping that will solve my air leaking problems for the most part. Do you have any suggestions for putting anything (insulating value) under the siding and if so will that cause any problems with double vapor barriers? I figure that will seal the wall itself up because the house is sheeted with 1 Xs.

Hi there Erich,

Any names involving "frozen" can use extra insulating :)

It is a matter of preference, but personally I would insulate via rigid foam board as opposed to firring the walls. Firring and increasing your fiberglass insulation is a completely viable option, but I find the rigid foam to be much less trouble and you can get up to R-8 out of it, exceeding your increase to R-19 on the inside.

If you already have rigid foam on the outside, there is nothing wrong with doubling up on it. Just straddle the joints. Don't attempt to put it on the inside, as it traps any moisture that makes it in into the wall cavities.

You can find some neat info on the board here (http://www.eere.energy.gov/consumer/your_home/insulation_airsealing/index.cfm/mytopic=11620) and you can find some more detailed info on the corresponding R values here (http://www.espenergy.com/foam_board_insulation.htm).

There's tons of ways to insulate, but since you're planning on doing the siding next season, this is the path I would take, barring any extenuating circumstances.

If you're dealing with improperly installed windows, I would take care of those first and get some insulation into those empty wall cavities.

thanks,
json

I keep getting those pesky post cards from Ohio Edison whining where is my money.

I know you can "get away with R-13" (anybody knows that) but if you're going to be doing the job yourself, the extra cost of the R-19 is not that much more. And why not spend the extra few dollars when the return of the heating and cooling benefit will be recouped in maybe one more month's non payment to your local utility company. Being in Wis in the winter with wind chills in the sub-arctic range can sure cool down your home in a jiffy. I vote for the R-19 anyday.

Yes, I agree about the sealing also. I think the people at GE Silicone are wondering if I dropped dead as I only purchased about 30 tubes of sealing from them when I sealed up my home. They keep sending me post cards also.

How dep is your wall cavity? If the cavity is a 2x4 stud wall R-19 is a waste because your would be compressiong it into the same air space as R-13. Insulation works by trapping air and if you compress insulation you will not be trapping more air than R-13. Adding more insulation to the attic is a great way to save money since you can pile it pretty deep without compressing it. Most heat is lost through the ceiling as compared to the walls. Be sure to not block any eave vents with added insulation, the attic must be able to breath.

first r 19 is for 2x6 walls and that's way overkill, r 13 is standard unless you live in extremes weather locations, so here's my opinion, if you can afford it go with r 15 that will save you some money, as for furring out walls I wouldn't bother with that

Glavine, we don't know where Erich lives so r19 may not be over kill. I am outside Chicago and wall cavities are 2x6 now with r19 minimum because of the cold in our region. Wisconsin and Minnesota are even worse. You are blessed with some nice weather in NC, we were 10 below zero last Wednesday and the 62 on Sunday.