Don’t Overlook Air Leakage Ratings on Replacement Windows

When buying replacement windows in Portland, OR energy efficiency is often a top priority. And rightfully so. One main reason to upgrade windows is to improve the insulation of the home. But most customers only consider the more prominent ratings like the U-factor and the Solar Heat Gain Coefficient (SHGC). What they need to understand is there is another rating it is important when determining a window’s ability to insulate and protect against heat loss. And when shopping for replacement windows, it is important to know as much as possible about the products.  

 

What is Air Leakage?  

Air leakage is another rating to consider and an important factor when purchasing new windows. Unfortunately, it is also one rating that often gets overlooked or misinterpreted. Granted, no window will perfectly seal against air leaks. Some amount of air will pass through the window assembly no matter what style of window it is. But that doesn’t mean new windows will leave you with the same draft problems you had with your old ones. The air leakage rating, also known as air infiltration, measures how much air is able to pass through the window assembly.  

 

How Do They Calculate Air Leakage?  

This rating is the amount of air that passes through the assembly determined by a constant wind speed of 25 miles per hour divided by the area of the window. This makes the unit of measurement is cubic feet per minute per square foot. These ratings go from 0.1 to 0.3cfm, and lower ratings mean less air infiltration. A home isn’t often exposed to constant 25 mph winds, but it is a good way to see how windows perform under more extreme circumstances. 

 

What Windows have the Best Air Leakage Ratings?  

Modern window advancements like engineered sash locking technology and weather-stripping help to reduce air leakage. The most airtight window styles are picture windows, awning windows, and casement windows. Sliding windows, single-hung, and double-hung windows have higher infiltration ratings. As far as materials go, vinyl windows with double or triple-glazing have excellent insulation properties and will help keep the air out of the home. Composite, fiberglass, and wood windows almost always have a higher air leakage rating.  

 

Why is the Air Infiltration Rating Important?  

It is easy to see why this measurement is critical when comparing replacement windows. What makes it difficult is that an air leakage rating is not required and some companies do not include it on the energy labels. It should be a concern if a company does not display the air leakage rating.  

 

The amount of air coming through a window is an important measurement, but air infiltration is just one rating to consider when shopping for replacement windows in Portland, OR. For help finding the right products for your home contact the experts at EnergyGuard Windows & Doors. They can help you choose designs and styles that will improve the efficiency of your home and reduce air infiltration.