Quick Answer: Oregon/Washington = 13-20 inches
Figure: 1
It's a frequently asked question among homeowners. One of the reasons this question is so frequently asked is that the answer varies depending on where you live and when your house was built.Different climates necessitate various types and amounts of insulation. Furthermore, by today's standards, most homes built before 2007 are under-insulated. Because of rising energy costs, even homes built in 2014 have more attic insulation than those built just four years before. Here's a quick checklist to help you determine how much attic insulation you need for your home.
How much insulation do you currently have? The first step in determining "How much insulation do I need?" is to measure your existing insulation, if any. Determine the depth of the insulation in inches using a ruler. Measure the distance from the floor to the top of the fill. If your attic is currently uninsulated, a higher R-Value (Resistance-Value) will be required to ensure that your home is properly insulated.
Where do you live in the temperate zone? Examine the ENERGY STAR map in Fig. 1 next. Locate your zone and then move on to the next number on the checklist below. Insulation requirements differ from state to state, and even from county to county. If you want a more personalized reading, the US Department of Energy offers this "how much insulation do I need calculator." Additionally, the government's Energy Codes website contains all of the specific Residential Prescriptive Requirements for your county and state.
How much attic insulation is required for Zones 1-4? The average minimum requirement for attic insulation in Zone 1 is 9 inches of R30 fill. The average recommended level of R49 is 16 inches. The average minimum requirement for attic insulation in Zone 2 is 9 inches of R30 fill. The average recommended level of R60 is 20 inches. The average minimum requirement for attic insulation in Zone 3 is 9 inches of R30 fill. The average recommended level of R60 is 17 inches. The average minimum requirement for attic insulation in Zone 4 is 13 inches of R38 fill. The average recommended level of R60 is 20 inches.
How much attic insulation is required for Zones 5-7? The average minimum requirement for attic insulation in Zone 5 is 13 inches of R38 fill. The average recommended level of R60 is 20 inches. The average minimum requirement for attic insulation in Zone 6 is 16 inches of R49 fill. The average recommended level of R60 is 20 inches.The average minimum requirement for attic insulation in Zone 7 is 16 inches of R49 fill. The average recommended level of R60 is 17 inches. As previously stated, before attempting anything on your own, please check your local codes and requirements, or simply call Flow Roofing for a free insulation inspection. You will not only learn how much attic insulation is required, but also how your new insulation will work.
