Question: Hi Ted,
I was wondering about the energy used in heating hot water. I have heard it is bout 20% of my utilities. I have also heard that by insulating it with 6 inch fiberglass will help to improve efficiency. What do you think?
Answer:

Ugh, I wrote a really long article in response and tumblr seems to have eaten it. 

I’ll try again after I get over the annoyance of losing this great post!

For now, start with the article on water heaters I wrote for my website.

Here’s part one of my answer as a full post.