Save time and money when brewing iced tea

Might not be the season for this post, but whatever. I brew my iced tea myself and store it in gallon container. I found I can cut down on time, energy and ice cubes (that water it down), by only boiling enough water to cover the tea bags in my pitcher. After letting it steep for 4 minutes, I fill the rest of the pitcher with cold water. I can't discern any difference in flavor from when I used to boil all the water. Plus, I find it lasts (unrefrigerated) just as long as tea that used 100% boiled water. (Conversely, if I make sun tea in the summer, I find it starts getting funky the next day unless it is refrigerated.) I like to refrigerate the tea, but sometimes I just don't have the room for a gallon container. If I want hot tea, I just microwave a cup of the tea from my pitcher...no waiting for it to steep.
Bonus tip: I read someplace that drinking a lot of tea can give you some type of stones (kidney, gall...I can't remember), but putting lemon in the tea solves that problem.