HOW TO KNOW YOU ARE GETTING THE INSULATION YOU PAID FOR
QUESTION FROM PATRICIA FROM TRENTON, TX:
I recently moved into a new home I built and am concerned over the high electric bills I am getting. I am thinking maybe I didn't get the insulation I was told I was purchasing. I was supposed to have gotten fiberglass blown in insulation with an R value of 49. I have measured the depth and it is 17" in most spaces (I can't tell at the far end of the house however and that is where it is the coldest). I have also measured the weight and for a 12"x12"x12" volume it is 0.75 pounds. Of course some areas of the attic have less than 17" maybe closer to 15".
Could you please let me know if I got what I paid for. Also my attic space seems warmer than it should. It is around 50 in the attic when it is 30 outside. What should the temp of the attic be?
ANSWER FROM THE INSULATION DOCTOR:
Thank you for your question. Regarding the number of inches required for blown-in fiberglass insulation, according to the specification sheet provided by Owens Corning an R-49 would require 19.5" as a "settled" weight.
For example, a year after your house has been insulated the insulation should measure 19.5". Generally a contractor would install approximately 21" to accommodate normal settling. If you were to go on the internet and check with the manufacturer of whatever brand was installed, you could find a specification sheet providing you with the exact measurement for the brand installed.
Regarding your attic temperature, if the outside temperature is 30 degrees for approximately 5 hours the temperature in your attic would be close to 35 degrees or maybe 40 if the sun is beating on your roof. You may have what is called hot spots in your attic. This results from insulation that has been installed that has been dropped down into soffits with the insulation not covering the sides of the soffits, thus allowing the heat to escape through the sides. Soffits are generally found in bathroom ceilings -- above showers, bathtubs or light fixtures over sinks.
A way to determine whether you have this problem is on a frosty or snowy morning (if you have snow in your area) go outside and from the ground level inspect your roof for areas that have no frost or snow. I would recommend that you contact your insulation contractor and ask them to verify the amount of insulation that was installed.
Most states require that they provide a certificate posted in the attic stating what was installed and by whom. It may be a case of an error in the order that was written to do the work or by the person who installed the insulation. It is best to give the contractor an opportunity to correct any problems that may have occurred prior to seeking legal restitution
A footnote, the above information is based on the fact that you do not have a furnace in your attic and that any heat runs that are in the attic are insulated. Hope this helps.
The Insulation Doctor