The Great Misconception
R-Value is a very important part of building a home or commercial building. R-value is the measurement of thermal resistance and heat retention through a particular insulating material. Many building regulations require a minimum R-Value to be achieved but this ranges from region to region. Although the minimum R-Value is usually low, around an R-13, many builders and homeowners strive to achieve the highest R-Value possible. This is where the misconception about R-Value starts to become apparent.
What are the numbers?
Many people get caught up on the idea that the highest R-Value walls are the most superior. However, this is not the case. Yes, there is slightly more thermal retention in an R-100 wall versus an R-30 wall, but the percentage is actually miniscule. The graph below illustrates how there is a very apparent trend of diminishing returns when it comes to R-Values past R-30. What it breaks down to is this: after an achieved R-25, 96% of all possible heat reduction slowly begins to diminish. Therefore, as more and more insulation is added, the reduction decreases at a minute rate and never achieves 100%. To clarify, when doubling the insulation to an R-50, the reduction in the flow of heat is only reduced by 2%. Doubling the R-value again to an R-100, only achieves an increase of 1% more than R-50. This means that even quadrupling the amount of R-value in a wall would only reduce the heat transfer 3%.
*provided by energyvanguard.com.
So what does this really mean?
This means that instead of looking for the wall system that offers the highest R-Value, we must look at the bigger picture. First, it is important to distinguish other elements of the walls we build. The difference between a wood framed wall with added insulation and an ICF wall for instance, is the benefits in the materials of the wall and the way it is constructed. With stick-framed walls, traditional 2X4 or 2X6 wood studs are framed in. Then standard roll in insulation is cut and added after the fact. With ICF walls the empty styrofoam form by itself provides a better insulation factor than most insulated wood framed walls. Once concrete and rebar are added, ICF block reach a minimum of R-40 in insulated value. Because of consolidated concrete core mass and the interlocking foam panels on both sides of the block, ICF’s are made to provide a “non-leaky”, air tight wall. Something that wood framing can never achieve. ICF’s are the highest quality in insulation due to the thermal heat displacement and resistance to moisture and unwanted drafts. ICF walls hold value in not only the finished product, but inherently in the materials used for the forms and in the way they are constructed.
Working Together: A Perfect Marriage
It is also imperative to look at what you are marrying the wall system with. What kind of windows and doors are being used? What kind of roof and floor system is the best? Builders and homeowners must develop an adequate justification in more insulation by a cost and climate zone condition evaluation. Overall energy savings can be greatly increased by choosing a floor and roof system that marry with the walls of a home or building. For example, Fox Blocks ICF walls marry nicely with iSpan Composite Total-Joist floors. ICF walls combined with a composite floor system and continuous insulation in foam bucks for doors and windows create a tighter building envelope. Using high quality insulated glass for windows and radiant heating for HVAC will also be an energy saver.
Answering the Equation
They key to true energy savings is a combination of all these things. The answer is not as simple as building walls with the maximum R-Value. Although R-Value is an important element in the walls of a home or commercial structure, building out of smart materials and doing a cost analysis of the benefits of ICF walls over traditional stick frame insulation is where we really see the solution. Overall, it is better to invest in an option that will be easy to use, save you time every step of the way and stand strong against natural disasters. ICF walls are the answer every time, and when married with other energy saving components you have the greenest, smartest and strongest home possible. Build for the future, Build Green with Forming Solutions.