Q. A neighbor, who not long ago had cellulose insulation blown into the outside walls of his home, says he expects to save about 15 percent on his heating bills. His house also has 6 inches of fiberglass ceiling insulation. Let me ask: (1) Is cellulose all right to use? (2) Is it as good as fiberglass or mineral-wool types? (3) Will fire-resistant treatment remain effective over the years? (6) Is a 15 percent heat saving realistic, recognizing the variations caused by location, the setting of the house, wind, and so on? (7) In general, would you recommend cellulose insulation or not? Edward F. Hudson Closter, N.J.
A. One manufacturer with an approved product is the National Cellulose Corporation, PO Box 45006, Houston, Texas 77045, (713) 433-6701, but there are others. Its product is called Celbar Loosefill insulation.
The following answers to your seven questions are based on claims for the above-named product:
1. Celbar Loosefull insulation is tested and listed by Underwriters Laboratories in accordance with government specification HH-I-515 C & D and is approved by the Southern Building Code.
2. It has a higher R-value per inch compared with mineral types. To obtain R-30, organic cellulose requires 8 inches of fill compared with rock woll (mineral), 10 inches, and fiberglass (mineral) 13.5 inches.
3. It will not settle to exceed the listed density of 2.5 pounds per cubic foot.
4. It will not wick (absorb) moisture from the air.
5. Its fireproofing will remain in effect unless it is subjected to a continued water flow, such as a roof leak.
6. A 15 percent projected energy saving by your neighbor sounds reasonable to me if heat-gain and heat-loss penetrations at doors and windows are resolved.
7. It can be installed in attics by the do-it-yourselfer; however, side-wall application may require an insulation contractor. We offer &gt;Continued on next page&gt; &gt;Continued from preceding page&gt; no advice one way or the other on cellulose insulation except to urge the use only of tested, approved, and certified products from reputable manufacturers which conform to federal specifications HH-I-515 C & D.
Avoid the "suede-shoe boys" who sell improperly manufactured cellulose insulation.
Yout can get in touch with the Cellulose Manufacturers Association, 5908 Colubia Pike, Bailey's Crossroads, Va. 22041, a trade group.
If you want to see the result of a two-year insulation materials study, write for Publication No. 5-BL-9363, 1979, Owens-Corning Fiberglas Corporation, Insulation Operating Division, Fiberglas Tower, Toledo, Ohio 45659.