R-19 vs. R-21 - Fine Homebuilding (2024)

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R-19 vs. R-21 - Fine Homebuilding (1)

emana| Posted in on

I am getting insulation quotes from various insulation contractors. One is spec’ing an R-19 insulation for 2×6 walls and another is quoting R-21 for 2×6 walls. The R-19 contractor is telling me that it won’t make a big difference as the r-value difference is small.

Any of you have experience or an opinion on this one?

Thanks!
Ed

Replies

  1. R-19 vs. R-21 - Fine Homebuilding (2)

    seeyou | |#1

    R21 is two more than R19.

    Actually, the type of insulation might make a big difference. This will serve as a bump until someone better versed comes along.

    http://logancustomcopper.com

    http://grantlogan.net/

    "We have enough youth, how about a fountain of smart?"

  2. R-19 vs. R-21 - Fine Homebuilding (3)

    sawzall | |#2

    you should be choosing betreen colours, not numbers.

    For insulation, there's pink, white, or yellow. You want pink.

    1. R-19 vs. R-21 - Fine Homebuilding (4)

      Grott | |#9

      In construction FG is OK for shingle matting and furnace filters... For insulation use foam or cellulose...Pink . . . this isn't the place to talk about that.

  3. R-19 vs. R-21 - Fine Homebuilding (5)

    rez | |#3

    Breaker Breaker 19 You got yer ears on eddie?

    Where you located?

    over...

    every court needs a jester

    1. R-19 vs. R-21 - Fine Homebuilding (6)

      emana | |#5

      Rez,I am in New York, over...Ed

      1. R-19 vs. R-21 - Fine Homebuilding (7)

        rez | |#6

        Well, a good heating climate then.

        That means you have to wait for someone more experienced to lend an ear or research the old insulation posts in the BT archives to familiarize yourself with insulation techniques other than fiberglass batt

        in that FBatts have been found to perform negatively in cold temps where the colder it gets the lessinsulation value asthe Rvalues decrease approaching near worthless.

        Thus the common consensus that FB ain't worth beans.

        Mooney Wall, high density cellulose, foam boards and sprayfoams all perform much muchbetter.

        Cheers

        be Happy Hunting

        every court needs a jester

        Edited 3/22/2007 10:33 pm ET by rez

  4. R-19 vs. R-21 - Fine Homebuilding (8)

    hipaul | |#4

    I don't know where you are, but in OR new construction requires R-21 for 2x6 framing.
    And sure R-21 is only 2 more than R-19, R-19 is only 4 more than R-15, which is only 2 more than R-13.
    If you get someone else telling you they can put some nice comfy blankets in your wall, I'd turn tail and run.

  5. R-19 vs. R-21 - Fine Homebuilding (9)

    BoJangles | |#7

    I wouldn't insulate my house with fiberglass if they gave it to me!

  6. R-19 vs. R-21 - Fine Homebuilding (10)

    Mongo | |#8

    Fiberglass is good for one thing: It makes cellulose and foam look that much better.

    Consider dense pack cells.

    Better at stopping air infiltration, better sound deadening, better at blocking radiant gain. And better at plain old insulating.

    Foam ain't so bad either if you cen do that.

    Mongo

  7. R-19 vs. R-21 - Fine Homebuilding (11)

    rpait | |#10

    If you go with anything above r-19 you might as well try for r-38. Heres why, although you may not notice right away the difference, as the electric company continues to increase the cost of electricity your home wont be affected as much because you willuse less to cool your house.

    The Electric company has done "cost vs value" reports on these things and use an "how long for return on investment" attitude when they recommend these things.

    The Elec Comp says r-19 is the most for C/V. However, You wont be able to add more insulation in 5 to 10 years when the heat causes the batts to compress and lose their insulative qualitys. I have seen 6 inch thick batts compressed to 2 inches over time. that being said-

    The most insulation you can possibly install now, the better for the long term.

    Additionally if you dont have adequate attic insulation, attic ventilation and highly energy efficient vinyl windows with low e etc then go with the r-19 and keep the windows open cause heat and energy inefficiency have many ways of getting into your home. Fixing one without fixing the rest is definately a waste of money!

  8. R-19 vs. R-21 - Fine Homebuilding (12)

    ErgoDesk | |#11

    Many new building systems use R-40 to R-120

    New Forum site: http://styrohomes.freeforums.org/

    1. R-19 vs. R-21 - Fine Homebuilding (13)

      rez | |#12

      Fatal error: Call to undefined function: http_redirect() in /home/www/phpbb/includes/db.php on line 63

      I never had a problem with character, people've been telling me I was one ever since I wasa kid.

      1. R-19 vs. R-21 - Fine Homebuilding (14)

        SamT | |#13

        http://ergodesk.wordpress.com/SamT

        Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. [Einstein] Tks, BossHogg.

        1. R-19 vs. R-21 - Fine Homebuilding (15)

          rez | |#14

          View Image

          I never had a problem with character, people've been telling me I was one ever since I wasa kid.

    2. R-19 vs. R-21 - Fine Homebuilding (16)

      paul42 | |#15

      Insulation is a fairly good long term investment – up to a point. If my increased mortgage costs are greater than the potential for energy bills savings, then it is pretty bad investment. In my climate, somewhere around R40 to R50 in the attic and around R14 in the walls is the practical maximum.

      <!----><!----><!---->

      It is also a fallacy to think that energy costs will continue to rise without stopping. My current electric rate is running around $.15 a KWH. Solar cells start to become cost effective somewhere around $.30 a KWH, even sooner if the cost of solar electric systems drop, and most experts believe they will.

      <!----><!---->

  9. R-19 vs. R-21 - Fine Homebuilding (17)

    CapnMac | |#16

    Cost difference would the first thing to look "at" for choosing.

    Then, it gets a tad esoteric. Two more "R" might be good in walls that have over 50% window & door openings (as the best windows run R2, R3; Doors can soar right up to 5 & 6--with reductions for being operable).

    There's an element of "bridging" unless one uses a Mooney wall that tends to obviate the "improvement" in R values, too. Now, if the extra 2 "R" is rigid over the sheathing, now, that's a way to "break" bridging, and that would be good.

    Leave the pink for the tract builders & for around cheap refrigerators.

    Occupational hazard of my occupation not being around (sorry Bubba)

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