Could be a safety thing. Many people die from carbon monoxide poisoning because of badly installed gas heaters.
Having them outside stops any build up of dangerous gasses
I had a house with the hot water heater in the garage. I came home one day to find a huge puddle of water in the garage when it failed. I was glad that water hadn’t damaged the interior of the house.
I have a tankless water heater and it’s mounted on the outside of the house.
I do not want to own a house with the hot water heater in the house. I have owned our house for 44 years. 2 times I determined that I needed a new water heater when there was water on the outside of the heater. No damage except I had a little clean up. If the heater was in the house there would have been damage.
A faulty hot water heater can do a lot more damage than leak water. This one killed seven people. And if you haven’t seen the famous Mythbusters test of a water heater with a deliberately disabled T&P valve, it’s worth watching. (Spoiler: the water heater blasted through the roof like a rocket and sailed over 500 feet straight up.)
Just out of curiousity: have people posting in this thread ever encountered a cold water heater?
I assume they also put toast in the toaster.
Here in Phoenix, it heats cold water in the winter, but it heats hot water in the summer.
But they don’t put make toast in the toast machine toaster.
It happened like that in adjacent suburb when I was living in an older part of town. The tank landed in the next block – pressure vessels are designed to preferentially blow out the bottom.
Outside water heaters are quite common in Hawaii. Not in our place, but I see them all the time.
I mentioned the same thing above. Here’s an apartment complex in Hawaii. https://ibb.co/LNd5F1k
Yep. That looks about right.
Outdoor exposed water and sewer pipes are also common because of weather. Single wall or bare brick walls are common as there’s generally no need for insulation.