I am planning to build a shed in the garden. I don't want it to be drafty so I am thinking o f getting energy efficient windows. While doing a bit of research online I came across a blog ( http://northtechwindows.ca/2017/02/15/much-difference-can-new-windows-make-energy-bill/ ) that mentioned some of the benefits. I am little tight financially and I don't want to spend a lot of money unnecessarily. Does anybody have energy efficient windows at home? Could you tell me about the pros and cons of it?Tia.