We replaced all of ours several years ago and it’s truly one of the best aesthetic upgrades we’ve done in my opinion. As far as energy savings, not so much for us. We don’t use AC, don’t even have it and barely turn the heat on in the winter. So it didn’t change our utility bill but I’m sure it can affect others with higher utilization. It does help with furniture fading which is a plus. I also open/close all the windows daily and the new windows move like a dream compared to the old ones.