“Layton Consulting Fenestration Nerds” By Anton Van Dyk: NetZero Windows. Do they exist?

When the BC Energy Step Code was introduced into BC, it was presented as a generic method of achieving higher performance.  Prior to the Energy Step Codes, municipalities, developers, and designers were using independent 3rd party standards as a means of demonstrating higher performance.  This could be Passive House, Energy Star, LEED Certified, etc.  The challenge with this process was that, in some cases, you needed a specialized certified product in order to meet some of the expectations.  This was seen as a bit of a barrier to moving forward as it would require manufacturers to certify products to several standards as opposed to one simplified code standard.

The BC Energy Step Code created a generic path for total home energy performance, leveraging the use of North American-certified products for items such as fenestration. This removed barriers for manufacturers and simplified the process of simply developing the highest performance window rather than changing the nuance of each unique standard. Simply put, CSA A440.2 and NFRC are the standards used. 

When it comes to the upper level of the BC Energy Step Code, we often see some of the more unique standards come into play.  The two most common are Passive House and NetZero (ready) Homes.  Both standards focus on total home energy use, so it can be less about the individual component and more about the overall performance.  So, the decision many manufacturers have to make is what is best for them.  Passive House has a fenestration certification process, while NetZero uses the current North American certification process.  BC has developed a method, however, for North American-certified windows to achieve a Passive House equivalency, but this still is a whole other step to take. 

What NetZero does is simply use the current tools manufacturers use for everyday product certification.  So, there are no extra certification steps to take.  An energy advisor who is doing the NetZero calculations will simply design within the North American (CSA A440.2 or NFRC) U value and Solar Heat Gain Coefficient values that are available.

So, what is a NetZero window?  Well, this window is often the best window at the best value.  The key here is that there is no real limit on the individual product as NetZero Homes focus on total energy use.  So, a window can have a lower rating if the walls have a higher rating and vice versa.  In cases like this, you can balance unique home design with performance and overall costs.  You are not simply using the best performance of every product. 

For a window manufacturer to consider supplying NetZero Homes with windows, start researching what U values are commonly used for NetZero Homes.  The key is it should be a range and not a line in the sand.  The range due to window performance is based on its window-to-wall ratio.  Larger window areas will require better U values as there is less wall insulation to make up the difference.  Once you have an idea of this range, you can start to review your product to determine what it will take to create U values within this range.   

This is where Thermal Research and Development comes in handy.  Thermal RND allows you to vet through design ideas on paper and via simulations before you have to commit to frame modifications.  Simply adding triple glazing with a full load of LowE may not be sufficient, and frame modifications, such as more chambers or insulation inserts, may be needed to achieve the outcome. 

So, are you ready to supply to NetZero Homes?  I bet you are, you just don’t know it.  If you have a product that can achieve U1.0 and lower, you are likely closer than you think.