Can cross-battens/ASV save energy in winter?

Dexter Q.
8/31/2015
The Oak Ridge National Lab did a study in 2006 saying that using batten/cross-batten/ASV with metal roofing will result in less heat lost at night during the winter, compared to asphalt shingles. They now call this above sheathing ventilation. Will using batten/cross-batten/ASV really save electricity in the winter while using a HEAT PUMP? Is the savings significant? Also, how common is this technique used to install standing seam panels(concealed fasteners)? Thanks
Todd Miller
Isaiah Industries, Inc.
8/31/2015
I looked up ORNL's report ... what they are saying I think is that the extra air gap helps slow down the loss of heat from the home. Perhaps they or Metro have more information but I am really not buying the concept that that will help reduce winter heating costs. Once the heat from inside the home passes through the insulation and into the attic, it will be lost. You're not going to heat your home with it, Whether it gets to the outside slowly or quickly, once it is through the insulation on top of the ceilings, it is gone. Now, f a house does not have a vented attic space, yes, it could possibly help to have the battens but generally I just don't buy the concept ... at least certainly not to the idea that it will have a significant impact on heating costs. And I certainly never have seen any claims as far as people saying that a metal roof on battens reduced their winter heating costs. I hope someone will correct me if I am wrong on this.
Guest User
9/24/2015
The heat loss in a ASV system is minimized by the airflow between the deck and roofing product. The airspace also allows a roof with a reflective surface like Zincalume on the underside to serve as a reflective barrier to maintain the "heated space" (gained from loss through the insulation) which will effect the overall lowering of consumption. Is this savings dramatic? The ORNL indicates that it may be almost as beneficial as the reduction of cooling costs in the summer. I know it has served me well in the 100 degree days in summer and the below zero days in winter in Utah.
Guest User
1/4/2016
I install different types of metal, including some that we install batten/counter batten system. I have customers that have actually tracked their kilowatt hours used with what they saved. I would be happy to share their letters to me if you like. I know it keeps my home warmer in winter than it was without them when i just had asphalt shingles, which was 15 years ago. Just how much savings, you would have to install them and measure it for your own home.
Dexter Q.
5/4/2016
Larry, Rob, Todd, thank you all for your helpful information. Larry , I would like to see some of your customer letters documenting their energy savings. Let me know what information I need to get to you to get it done. Thanks very much!!!
Guest User
8/25/2016
Yes, please, can you share those letters? We live in Denver, where we have hot summers and cold winters. I can easily see how counter-battens with a metal roof will help keep it cool in summer - but in winter? During the winter we often have very cold days with lots of sunshine - and it seems our house (with wood shake) is definitely warmer on those days than on days of the same temperature when it's cloudy. I assumed that was from heat gain in the attic from the sunshine. I guess I can see how counter-batten would prevent some of the conductive heat loss from in the attic to the exterior - and that seemed to be what that report from the National Laboratories showed - but it also would prevent transfer of heat from the sun into the home in the winter just like it does in the summer. Here in Denver I suspect that beneficial heat gain would be worth more than avoiding the heat loss. One reason counter-batten installation is used in mountain homes here in Colorado (i.e. Vail, where it is significantly colder) is to keep the roof colder, so you avoid the freeze-thaw-refreeze that can result in ice-damns, etc. Here in Denver I'm told that is not a major consideration- the roof with standard installation is resistant to that due to the impermeability of the metal top layer. We're considering whether the counter-battens are worth the extra $$ - it's pretty minor actually ($25K vs $23K I think) - but I was more concerned about heating bills in the winter. Our contractor, who is great, says it saves money in summer and winter, but I'm having trouble verifying that- and it seems too good to be true. We probably will beef up the attic insulation as well - but, well, that's kind of not the point of this thread! Thanks!
Dexter Q.
8/25/2016
To Paul, I am currently planning to install a standing seam metal roof from a metal roofing manufacturer that incorporates ASV without using battens/cross battens.

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