Today was a sunnier day than the past few days. I decided to try out some reflector on my black hot water bottles. I can't say for sure that it made a huge difference. The water was definitely hotter than it has been the past few days but there was more sun. I'd like to see if I could cover it with a towel or something and conserve the heat.(I'd really like to have a wooden box with a glass lid.) I'll be busy this weekend and might not be home in time for a really hot shower. I'm ok with a warm one though.