American Ingenuity’s component panels for the 15′ – 48′ domes contains seven inch thick rigid Expanded Polystyrene (E.P.S.) insulation which has an R value of 28. The seven inch thick insulation is comparable to eleven inch thick fiberglass batting. There is no wood in the American Ingenuity Dome shell to interrupt the insulation or to rot or to be eaten by termites or to burn. However, a temporary wooden rib system is utilized to support the panels during the dome assembly until all the seams between the panels and the entryways and dormers are concreted and then the system comes down. The dome is self supporting. The exterior is steel reinforced concrete that is primed and painted. Your locally purchased doors and windows are installed in pressure treated wood framed wall under the entryway and dormer panels.
1. What’s the benefit of insulating my home?
- Insulation can help reduce the cost of your heating and cooling bills by preventing the flow of heat into your house in the summer time and reducing the flow of heat out of your home in the winter time. In short, you can save money.
2. What’s the most important thing to know about insulation?
- Its “R-value.” The R-value of an insulation product gauges the resistance the insulation has to the flow of heat.The higher the R-value, the better the product will resist heat flow. R-values are standardized, so you can compare different brands and types of insulation, and still know their relative ability to resist heat flow.
We have all heard builders claim to build “R-13” or “R-21” walls with wood frame construction. The problem is that only the highest rated component in the wall – the insulation itself – performs at these stated R-values. A wood frame wall is made up of several components, not all of which have the same R-value. For instance, a 2×4 or 2×6 stud has an R-value of about R-5 or R-7. Every 16 inches or so, one of these components breaks the insulation layer and forms a “thermal bridge”, conducting heat through the walls at high rates in addition to being a major cause of mold in standard construction. Adding up the area of studs, plates, and headers, 12% to 16% of the total wall area is an R-5 or R-7 thermal bridge, all detracting from the stated R-value. In addition, batt insulation tends to sag over time and leave spaces without any insulation! How can those builders claim only the highest-component R-value? From a whole-wall perspective, framed walls operate at far lower R-values – sometimes only half of the advertised value.
American Ingenuity’s (Ai’s) prefab panel contains seven inch thick Expanded polystyrene (EPS) insulation which consists of a solid piece of EPS that provides a continuous layer of insulation rated at R28. From a whole-wall perspective, an EPS wall actually lives up to the advertised R-values because thermal bridging is absent.
Thermal conduction is not the only mode of energy loss in a building. In fact, conduction often contributes less to energy losses in wood frame buildings than convection, which is not even measured by R-values.
Thermal Convection is heat transfer by movement of currents within fluids or gases. When considering energy performance of buildings, it’s the air moving between the inside and outside or “air infiltration”. A common measurement is ‘Air Changes per Hour’ at a blower-door induced pressure differential of 50 Pascal (ACH50). US Energy Star standards for new homes require less than 4-7 ACH50. In comparison, Canadian R-2000 standards are 1.5 ACH50, and Swedish standards are 0.5 ACH50 or less.
- In wood frame buildings convection can be felt as drafts and is usually the biggest source of energy loss. Air infiltration accounts for up to 40% of the energy losses of a wood framed structure. Energy escapes via conditioned air leaking through thousands of cracks, openings, and joints between all the “matchsticks” of the building shell. Major culprits include framing connections, wall, floor & roof intersections, shrinkage of wood and caulking, and poor installation of components and sealants. A typical new wood frame home has between 1.75 and 3 air changes per hour (ACH50) and after some years it’s often between 5 and 10 ACH50 as the wood shrinks and sealants deteriorate. Old wood frame homes commonly have 10 to 20 ACH50.
- EPS walls & roofs are an effective air (and vapor) barrier because the concrete is solid without passages for air to leak, thus eliminating a major percentage of air infiltration. EPS buildings consistently get results of 0.5 to 2.5 ACH50 and less, largely depending on the installed roof type and sealing. Most air infiltration in an EPS home is through a conventional roof and around windows & doors, so pay attention to these areas. Adequate air exchange in very airtight buildings must be ensured, typically using mechanical ventilation. Mechanical ventilation can be combined with ‘heat/energy-recovery’ units and/or ground heat exchangers for additional savings where conditions & budgets allow it.
R-Value Table: Insulation Values For Selected Materials
Use the R-value table below to help you determine the R-value of your wall or ceiling assemblies. To obtain a wall or ceiling assembly R-value you must add the r-values of the individual components together.
This method ‘Wall Assembly R-Value” gives incorrect results for MASS walls such as the All Wall System.
Example of error, as defined by ORNL research papers.
When compared to a 6” R-20 framed Wood Wall a Foam Block (ICF) wall performed with a 9% better Energy Savings.
A wall built like All Wall performed with an 18% better Energy Savings. (9% over the Foam Block walls) because of the concrete being in direct contact with the interior.
See ORNL’s report conclusions by clicking here. Oakridge National Laboratory
Example:Wall Assembly R-Value Example:
|Wall – Outside Air Film||0.17|
|Siding – Wood Bevel||0.80|
|Plywood Sheathing – 1/2″||0.63|
|3 1/2″ Fiberglass Bat||11.00|
|Inside Air Film||0.68|
|Total Wall Assembly R-Value||13.73|
|Fiberglass Blown (attic)||2.20|
|Fiberglass Blown (wall)||3.20|
|Rock Wool Bat||3.14|
|Rock Wool Blown (attic)||3.10|
|Rock Wool Blown (wall)||3.03|
|Cellulose Blown (attic)||3.13|
|Cellulose Blown (wall)||3.70|
|Urea terpolymer foam||4.48|
|Rigid Fiberglass (> 4lb/ft3)||4.00|
|Expanded Polystyrene (beadboard)||4.00|
|Concrete Block 4″||0.80|
|Concrete Block 8″||1.11|
|Concrete Block 12″||1.28|
|Brick 4″ common||0.80|
|Brick 4″ face||0.44|
|Soft Wood Lumber||1.25|
|2″ nominal (1 1/2″)||1.88|
|2×4 (3 1/2″)||4.38|
|2×6 (5 1/2″)||6.88|
|Cedar Logs and Lumber||1.33|
|Extruded Polystyrene (3/4″)||3.75|
|Wood Bevel Lapped||0.80|
|Aluminum, Steel, Vinyl
|(w/ 1/2″ Insulating board)||1.80|
|Interior Finish Materials|
|Gypsum Board (drywall 1/2″)||0.45|
|Particle Board (underlayment)||1.31|
|Carpet (fibrous pad)||2.08|
|Double insulating glass
(3/16″) air space
|(1/4″ air space)||1.69|
|(1/2″ air space)||2.04|
|(3/4″ air space)||2.38|
|(1/2″ w/ Low-E 0.20)||3.13|
|(w/ suspended film)||2.77|
|(w/ 2 suspended films)||3.85|
|(w/ suspended film and low-E)||4.05|
|Triple insulating glass
(1/4″ air spaces)
|(1/2″ air spaces)||3.23|
|Addition for tight fitting drapes or shades, or closed blinds||0.29|
|Wood Hollow Core Flush
|Solid Core Flush (1 3/4″)||3.03|
|Solid Core Flush (2 1/4″)||3.70|
|Panel Door w/ 7/16″ Panels
|Storm Door (wood 50% glass)||1.25|
(2″ w/ urethane)
|1/2″ to 4″ approximately||1.00|