Very few of the old windows hold up to the modern quality and Energy Efficiency standards. Ever rising cooling and heating costs puts Replacement Windows on the top 3 list of improvements that save you money, create comfort, improve looks, and increase the value of your home.  

Multi-chamber Vinyl profile (uPVC) is the most popular frame material these days.  It is the best value and the most practical solution that offers the unbeatable combination of strength, durability, looks, zero maintenance, and price there is.

The efficiency of a window is largely defined by its glazing. After all, most of a window's surface is glass. Aztech Doors & Windows manufactures and installs Energy Efficient Windows with the glazing units with 2 or 3 panes of glass separated by SuperSpacer^TM, inner volume filled with the noble gas (Argon or Krypton), and sealed with resin to keep the gas inside.  One of the glass panes is also coated with LoE film which further improves the efficiency and protects home's interior from harmful UV radiation coming from the sun.
 
To read more or to check the specific product rating please visit the Energy Star website.