Replacement Window Performance - Part 1: Through the Looking Glass

When deciding on which replacement windows you would like to purchase there are many things to consider in order to achieve the highest energy efficiency and highest longevity of the actual window. The first consideration you need to determine is how to get the best view with the highest structural integrity.  There are two visual inspections that you need to do that will help you compare different brands to achieve this goal.

The first: Can I see through the window?

This might seem like an obvious and simple question, until you realize that many vinyl replacement windows have very wide profiles that significantly reduce the overall amount of glass in the unit.  Comparing different vinyl windows will allow you see just how much glass size can vary between manufacturers. 

In contrast, the HiMark 500 has one of the narrowest profile frame windows on the market today with the HiMark 800 being only slightly thicker.  Their proprietary design accomplishes this without losing strength in the structure of the unit.  The HiMark 500 is a DP-50 (+170 mph wind load) and the HiMark 800 is a DP-60 (+190 mph wind load).  We have chosen these windows to offer our customers because they offer the maximum glass while still maintaining a high structural quality.

The second: How dark is glass?

What are the VT (Visible Transmittance) Ratings?  This rating determines how much light passes through the glass of the window.  Depending on the manufacturer's application of Low-E coating, the glass can have a dark appearance with a higher VT rating.  The HiMark 500/800 also demonstrate outstanding thermal numbers with a 2 coat Low-e, as opposed to a 3 coat Low-e.  Less Low-e = Less tint and more light. Many window manufactures tout a 3 coat Low-e application as a prime feature of their windows, however, the 3 coat Low-e has no application value for our climate region (the Mid-Atlantic) as it blocks out too much of the sun's warming rays and eliminates and passive winter sun.  There are exhaustive studies that demonstrate that an improperly selected Low-e range for this climate will actually make your window less efficient.  3 coat Low-e is reserved for regions that are dominated by cooling seasons (i.e. Florida, Texas, etc).  Therefore, there’s no reason to incur the expense or reduction in visible light with its’ application to the unit.

Windows on Washington’s goal is 100% customer satisfaction as the windows you purchase from us are for a lifetime.  Please let us know if you have any questions about the profile or Visible Transmittance of your windows.  Look to this blog in the coming days for more helpful information about replacement window performance.