How to reach an R – Value of close to 100
Or what is it the home owner is looking for. The researchers and producers of materials needed a way to evaluate their products and to bring it in mathematical formulas.
A Homeowner would not understand these technical expressions but any kid would understand that if the bill for electricity, gas, oil etc is xxx-amount a year and you can drop this number by 80% and more, that in long term this means SAVINGS.
So here I want to give an understanding of what we are talking when we talk about thermal mass & R – Value.
Center-of-Cavity R-value: R-value estimation at a point in the wall's cross-sectional R-value containing the most insulation.
Clear wall R-value: R-value estimation for the exterior wall area containing only insulation and necessary framing materials for a clear section with no fenestrations, corners, or connections between other envelope elements such as roofs, foundations, and other walls.
Interface details: A set of common structural connections between the exterior wall and other envelope components, such as wall/wall (corners), wall /roof, wall/floor, window header, window sill, door jam, door header, and window jamb, that make up a representative residential whole-wall elevation.
Whole-wall R-value:R-value estimation for the whole opaque wall including the thermal performance of not only the "clear wall" area, with insulation and structural elements, but also typical envelope interface details, including wall/wall (corners), wall /roof, wall/floor, wall/door, and wall/window connections.
|
Type of Insulation |
Fiberglass, blankets or loose-fill |
Cellulose, loose-fill |
Mineral wool, blankets of loose-fill |
Foam board, white |
Foam board, blue or pink |
Polyurethane |
|
R-Value per Inch |
2.9 - 3.5 |
3.5 |
3.0 |
3.8 |
5.0 |
6.5 |
It is possible to build a house that is using no external energy, but it will need a extra installation of solar to generate the energy. I believe so far that an R – value above 80 is a good way to go. I have spoken to clients that live in their passive homes since 6-9 years and they all tell me the same about their savings. I can bring $3000-$4000 a year to the bank to lower the mortgage or I use this money for a nice vacation. And never forget the test from the energy producers in summer 2008, when prices went up 100%.
Enjoy life
Hoowood