David White Releases Global Warming Potential Calculator for Insulation.

The issue of Global Warming Potential (GWP) of insulation, first brought to the forefront of the building performance industry last year when Alex Wilson wrote an influential article about it in Environmental Building News, has been a major bump in the road for the home performance industry.

Soon after the publication of “Avoiding the Global Warming Impact of Insulation,” Michael Anschel wrote a similarly controversial post on Remodeling Magazine Online suggesting that, until we can figure out how to do it right, we should just stop trying to fix our houses, because we may be doing more harm than good. This is a spookily tempting suggestion: even I, needing an air sealing and R-value solution to the uninsulated rim joists at my house, got hung up by the Global Warming Potential of the closed cell foam that is often the go-to solution for fixing this very typical problem. I fretted and procrastinated, harassed my auditor and contractor endlessly, and, frankly, still haven’t tackled this particular measure.

My personal situation illustrates how dangerous the GWP issue can be, in that it threatens to inject paralysis into the fledgling industry seeking to drive energy efficiency retrofits of our energy-wasting buildings. (I rebutted Michael’s point in a guest blog post on Remodeling with this argument.) After all, the benefits of improving the energy efficiency of our building stock are many: comfort, financial savings, geopolitical considerations and energy efficiency all going hand in hand with climate change mitigation efforts. But the early adopters of energy efficiency include many people motivated primarily by climate change, and scaring off the true green segment, well, would be bad. We needed a tool to weigh the concerns about material GWP against their benefits in a scientific, data-driven, empirical way.

Well, now we have one. Yesterday at the NESEA Building Energy 2011 Conference in Boston, David White of Right Environments released a GWP calculator for insulation materials that does just this.

The tool essentially determines two important things, based on a number of variables:

1) Whether a building would benefit from additional insulation enough to justify the GWP of the added insulation, and,

2) If there are better alternatives to the insulation you were planning on using.

Variables that the tool takes into consideration include the climate in which the building is located (heating degree days), R-value of insulation materials, embodied energy of insulation materials, projected life of the building, fuel type, and more.

As David indicates in his notes, the tool should be used in combination with other variables – health, comfort, cost, to name a few – to make informed decisions regarding insulation material choice. But, while admittedly limited in its scope, it just may remove the sense of paralysis that the issue of Global Warming Potential threatened to incur.

We'd like to commend David White for creating this game-changing tool for green builders, home performance contractors, architects and remodelers as we move forward in creating a healthier, more efficient built environment.

To download the tool (for free), visit Right Environments' Free Downloads page. And next time you see David, buy him a beer. 

Here's a screenshot, and a partial explanation:

GPW Insulation Tool


Game changing - maybe for some
Fundamentally flawed - definitely

Just at first glance - only hdd, no cdd & even if you add them in, there is no way of showing what the supposed effects are of not installing X amount of insulation

Next onto the GWP itself - if anyone has ever seriously looked into it, the word potential is very accurate as they specifically mention a combined 25-40% fudge factor in their calculations as all they are taking is a WAG (3 guess on which way they push the numbers)

As for building life - if we truly are building "green" and becoming more enlightened, there should be no reason to open up the walls or demolishing the structure after 50 years

I remember a real simple saying, which aptly applies in this case - garbage in = garbage out

Please read the original article mentioned at the beginning of this article first, or you come to false conclusions.

1. Insulation is always good, except for XPS and SPF (if they use blowing agents with high Global Warming Potential). Commenter Wolfgang Feist - the inventor of the Passive House concept wrote - that in Europe XPS is produced without any FCKW with high GWP.

2. All other insulation materials are really good in slowing Global Warming.

3. I also think that 50 years are not enough for the calculator. 80 to 100 years is more realistic. I think this is the big difference between Europe and the US - Europe is building for the next century, the US is building for up to the next major renovation.

4. If you think of the Passive House Concept which main conclusion is to insulate to levels where you don't need a heating system anymore - does the presented calculator take into account the saved embodied energy of no heating system (furnace/ducts/labor/transport etc.) and of no production/transport of the saved oil/gas. You can't make simple assumptions or you come to false conclusions.

Therefore use a Systems Approach for your house. If you use spray foam (bad GWP - but not always) for air tightening your house and use for example high levels of high density cellulose insulation (low GWP) for reducing the heat losses to almost the same amount as the heat gains (solar), you will be able to use the ventilation for heating purposes and healthier indoor air and use a heat recovery ventilator to heat the water with the recovered energy. The sum of all these details defines the Passive House Concept. Please take the time to read through the quite simple principles. http://www.passivehouse.us/passiveHouse/PassiveHouseInfo.html

Now, how much insulation is enough? Use the Passive House Passive House Planning Package Software (PHPP), a detailed building modeling software for new construction or renovation that yields very accurate results better than other software methods. But only trained professionals will get good results with this detailed software. http://www.passivehouse.us/passiveHouse/DesignTools.html

At the end of your renovations a small PV System on your very efficient house will provide electricity and “fuel” for your Battery Electric or plugin hybrid vehicle.

My conclusion is: Don't stop insulating, just us the right materials. Only looking at insulation is not the solution, it's imperative to use a System Approach – and in my opinion the best systems approach is the Passive House.

Diego Matter
BPI certified specialist

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