# PVC and poly iso



## morrissey roofing (Nov 28, 2010)

Thanks in advance
Does anyone know where I can calculate the percentage, not actual dollar value, of upgrading from 1.5 inch poly iso to 4.0 poly iso?
Here is my scenario...445 square, Connecticut, industrial use, 1 floor, metal deck. Currently has 1.5 inches, 060 fully adhered Genflex EPDM. Roof is 7 years old, seams are starting to go.
Building owner wants to start saving some money, we just installed 3 6 ton ACs, and now they want to either coat the roof with seam restoration, or ass 2.5 inches of polyiso and go with a 50mil PVC, and well, my brain is fried, i can price the job, but can't show real numbers in evergy savings...any help available?


----------



## 1985gt (Dec 21, 2010)

Well I don't have any experiance figuring out how much he will actually save but 1.5" if Iso is a R of 9, adding another 2.5 will give it an addition R 15.3. Also depending how deteriorated the ISO is underneath it will also affect it too. I'm sure there is some formula on the internet that will help to figure it out, then again it also has a lot of variables. 

Um good luck


----------



## Pie in the Sky (Dec 21, 2011)

Very Basic 

http://www.builditsolar.com/References/Calculators/InsulUpgrd/InsulUpgrade.htm

I would subtract 15% for Variables that I am sure the calculator doesnt take into account. 

I am pretty sure Hunter Panels offers this service too. Or you can pay someone to do an energy model which will be more accurate. For instance: Roof insulation is very important for lowering energy loss, but it doesnt do much when the building is made out of glass.


----------



## Grumpy (Oct 29, 2008)

Versico has a similar service for registered contractors.


----------



## morrissey roofing (Nov 28, 2010)

Thanks all, I found a bunch of different resources eventually....so if your ready...going from 060 EPDM with 1.5 poly iso to 060 PVC white saves 7% to 10% on cooling costs, adding 3 more inches of iso saves them $13,600 on heating costs a year, I think if we all marketed these savings more we could sell more PVC and make more money.....


----------



## Grumpy (Oct 29, 2008)

I won't market these savings and here is why; It's like Pie said: http://www.roofingtalk.com/f7/pvc-poly-iso-2022/#post15063 


I'm not going to tell someone they will save $x or x% because I am opening up myself to liability. If we have an unusually cold winter and their heating bill doesn't change, I am in court defending my claim that they would save $x or x%. If someone leaves a window or door open all winter, I am in court defending my claim that they would save $x or x%. 

It's like window guys claiming "you'll save 30% on your heating bills with out thermally insulated windows." Several years ago when I used to sell windows, when people would ask "how much am I going to save on my energy bills?" I knew they had a slick willy salesman in before me. I would always reply, "I don't know, nor does anyone. some of your heat loss/gain is through the windows. Some is through the ceiling/roof. Some right through the walls. Nobody can tell you how much you will save without first measuring all areas of the structure for insulation, ventilation, vapor barrier etc... Otherwise they're just throwing out funny numbers."

So if you go tell your customer they are going to save $13k and they don't save $13k I hope you have a good lawyer.


I do tell people about reflectivity when it comes to roofing. It's part of every one of my presentations. I do also tell them about insulation, and depending on deck type ventilation. It's part of my presentation to set myself apart. However I will not talk about hard numbers, there is just really no way to accurate predict. "This membrane is white making it highly reflective. That's good for a few reasons, not only does it exceed the new energy code reflectivity requirements, but that reflectivity also helps relfect away heat. The white membrane will be much much cooler to the touch than a traditional black membrane, and this equates with less heat transfer into the structure. Insulation is also important and now is the time to insulate...." Then I go on to talk about warm deck or cold deck designs. You wouldn't believe how many jobs I sell based on the warm deck cold deck insulation practices because most of our flat jobs are on wood substrates.


Edit: By the way, you know there are other reflective membranes besides just PVC, right? I like PVC my crew is installing it as I type. I prefer it as a matter of fact, however TPO is equally as reflective, cool star modified, white epdm etc... All I am saying is don't tell the customer they need PVC because it is reflective when there are numerous other reflective membranes as well.


----------



## Pie in the Sky (Dec 21, 2011)

I have done some work with reflectivity too.. I find in most of the northern climates I work,(with a properly insulated roof) you don’t really see much of a difference with a white roof (versus EPDM). If it is a Big Building that Cools all summer, the cooler surface of the roof actually makes the units operate more Efficiently. But let’s say we put a white roof on a school, they have very few people in the school all summer so cooling costs are low anyway. Then if we get into how many people are inside while the units are operating. That changes everything too. 
And yet another variable, the thermal mass of EPDM is low, it cools down as soon as the sun comes off where BUR holds onto it. 

One other thing, Just an FYI. I’ve been involved with dozens of analysis like this, after 4-5" of ISO the effects are diminishing. Also there is no Payback beyond an R-24-26. We had to re-do these calc’s for every Government building where they were requiring an R-50! They still would put it on.
D


----------



## Grumpy (Oct 29, 2008)

Pie in the Sky said:


> I Also there is no Payback beyond an R-24-26. We had to re-do these calc’s for every Government building where they were requiring an R-50! They still would put it on.
> D


That's why my GD taxes are so GD high.


----------

