Insulated Double Walls
Boost insulation on new walls from R-19 to R-30. Create a 2x10 wall (2x6 exterior structure with 2x4 interior). You may achieve similar benefits by using 2X10 studs instead of the composite double wall. However, you may lose the 'thermal break' created by a small air gap left between the two stud system. That same air gap also has an audio advantage in breaking sound waves to keep your home quiet and comfortable. Think of an inefficient house as wearing a flannel shirt, an efficient house with an added sweater, and a high performance house with the shirt, sweater, and a parka. In addition to energy savings, you get better sound protection since the double wall diffuses the sound waves.
Offset the interior studs to diffuse sound waves or run horizontal spacing boards between the walls. The deeper sill at windows is a great visual feature. Spray-in insulation gives you the best performance, because it fills all of the crevices. Select a 'Formaldehyde-Free' insulation to save on air quality and health. A carpenter can frame about 6 lineal ft of wall / hour with 16" on center studs, plus both top and bottom plates and fasteners.
The ROI Calculation is based on adding interior studs prior to the sheet rock, so you only pay once for finishing/painting. For a 30' long wall 8' high, this factors in an additional $500 labor, $250 insulation, and $150 studs, and savings of $10 a month. Plus consider the tax credits.
Tax CreditsThe American Recovery and Reinvestment Act (ARRA) provides you with a 30% Tax Credit for Insulated Double Walls that are put into service by the end of 2010. This tax credit item is only for existing homes, not new construction, that is your primary residence and it includes ONLY the cost of materials and NOT installation.
3 KEY POINTS -
- The tax credit cap is $1,500 on collective home improvement elements other than Geo-Thermal 'Ground Source' Heat Pumps, Solar Hot Water Heating, Solar Photovoltaic, and Fuel Cell systems - which each have no cap and are eligible through 2016.
- The tax credits for exterior 'weatherization' improvements like windows, doors and insulation do not include the cost of installation!
- If you reach the $1,500 cap in 2009, you are not eligible for additional tax credits in 2010.
Choose Insulation for Double Walls that meet these criteria to get the Tax Credit; and check products carefully, because in many cases an ENERGY STAR certification does not necessarily meet the tax credit requirements below:
- Must meet 2009 IECC & Amendments
- For insulation to qualify, its primary purpose must be to insulate (Example: vapor retarders are covered, insulated siding does not qualify).
- Must be expected to last 5 years OR have a 2-year warranty.
- Please note that qualified insulated attic hatch and stair covers will count for the tax credit and they often have a very high return on investment.
- To qualify for the Federal tax credit, homeowners must only meet the level of insulation required for the area they are insulating. For example, a homeowner can choose only to insulate their attic to the levels required in the 2009 IECC and still be eligible for the tax credit. For most homeowners, this will mean adding an additional R-19 to R-30 insulation to their attic. If a homeowner insulates part of their home to a level below the 2009 IECC, this would not qualify.
- Required insulation levels will vary by region and will include insulation that is already installed in your home. For an idea of required Insulation levels, check out this map by the North American Insulation Manufacturers Association.
For a lower level or basement, that in this case is a walk-out, you can see the yellow side of the insulation that is set in the interior wall before the extra deep window casing and sill is cut into place.
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Tax CreditsClick Here
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The deep sill and door frame bounce light into the room, frame views, and have the insulation benefits. The garden shed in the background, however, houses the tools of the trade which have little, if any, of the same benefits.