My brother has just moved out by himself for the first time. In the deluge of “new home-user” advice he’s received, he heard a recommendation that he wrap his water heater in a blanket, so that he loses less heat into the air. He’s concerned that said blanket could ignite, so he asked me to ask you guys what he should do. It’s a natural-gas heater.
I would not just wrap any old blanket around a water heater. I’d get one specifically made for the purpose.
I thought about wrapping my water heater, but it’s a high-efficiency one and I cannot feel any heat escaping from the sides. I suppose I could wrap the pipes, but I don’t know if it would be worth it. Since my water heater is in an odd place (inside the smallest bedroom) I built an enclosure around it. Since the heater is inside of the house and the enclosure is pretty snug, I figured that would hold in the little waste heat there is well enough.
EDIT:
Mine’s electric.
Yes, get one specifically designed for the purpose.
I am going to be doing this in my house soon, I think. My heater’s sitting in the middle of my cold basement.
As long as you get one made for this purpose - designed to not catch on fire - it can’t hurt, right?
I’ve been told by contractors from two different heating places that I should not wrap a contemporary water heater with anything because it causes condensation between the insulation and the tank and that this can shorten the life of the heater. I can’t evaluate the truth of these claims.
While I’m hesitant to doubt them, especially when they would have every reason to want to sell someone a blanket, I nonetheless have some trouble envisioning how this would happen, nor have I ever encountered it. The DoE still recommends very highly using thermal blankets designed for the purpose to wrap water heaters.
Another thing to do - buy the thick pipe insulation and insulate the hot water pipes wherever you possibly can. Be careful with the pipes where they are near to the flue (if it’s a gas heater), as I thought I was careful, and nonetheless melted some pipe insulation. It could be a fire risk if you get insulation too close to the flue.
Water heater insulation can be a huge money savings over time. I’ve read test reports of savings of $2-$15 per month, and given that the insulation costs so little, you could have a payback period of well under a year.
IANAContractor, but it seems highly unlikely to me that the gap between the insulation and tank would be below the dew point of the room. Unless the water heater is turned off and the water inside is allowed to cool down to room temperature.
I moved my mechanical room and built a utility/laundry room. I have two hot water heaters in there. One for heating the in floor heat in the room, and one for our domestic hot water.
:shrug: Any heat that comes off of the hot water heater(s) is coming right into my house.
It really depends on where the heater is IMHO.
True (a similar argument is made with incandescent lighting), but in summer time it would increase your cooling load. Unless you don’t use air conditioning there in Colorado, which is certainly possible?
My water heater is in the garage, if that helps.
Well, if we think about why condensation occurs - it occurs because the dew point of the air is such that the water in it can condense - in effect, the air is at saturation with respect to how much water it can hold. As the temperature increases, more water can be held in the air before it will start to condense back out.
Now, just based on IME with water heaters, I would say that the outer skin of an average water heater would be about 100-110F, possibly much more. At that temperature, quite a bit of water could be held in the air before it would start to condense out. While a garage would be exposed to higher humidity air than in a house, I still have difficulty imagining air at 100-110F condensing out much in the way of moisture. For that to happen, the outside air would have to be something like 120-130F and have quite a bit of humidity in it. I mean, in effect, the ambient air would have to be given a reason to condense, and the most common reason is that the temperature is reduced below the saturation point.
Because water heaters are generally hotter than anything around them, I’ve never seen condensation be an issue with them. The only possible thing I could think of is that there may be condensation on the cold-water line coming into the heater (and typically, via conduction these lines are somewhat warm anyhow) and water condenses on that line, then drips onto the tank and pools there, or runs down the side. That seems a stretch to me…
**^^^**In Captain Dummy Speak:
Water condenses on the outside of cold things, like a glass of iced tea, not hot things like a steaming coffee mug.
Anecdotes follow:
I can only report that the outside of my water heater is cool to the touch. The temperature in the garage today is 64F, and the water heater certainly is no warmer than that, though it is set to heat water to 120-130F, which it does.
While the water heater in my parents’ house was often warm to the touch, mine never have been. They have been newer, and I presume double-walled or internally insulated in some way. When we bought the house the water heater was wrapped in a fiberglass blanket intended for the purpose. there was a certain amount of mold underneath when we removed it.
Well, if the outer skin is cool to the touch, then most likely you have insulation that is already good enough, and adding a blanket may indeed cause condensation. If your water heater was older, or poorly insulated, and was very warm to the touch, then it might do some good. But overall, it sounds like your heater is doing quite well.
One might nonetheless consider adding hot water pipe insulation, if not already installed.
That, I’ve done!
Something I’ve heard that helps is to install a heat trap. It’s a section of pipe on the outlet side, near the unit that goes down and back up (or up and back down). Without it, the heater will heat the water in the pipe all the way up to the highest point, the pipe effectivly becomes part of the tank. Since the pipe isn’t insulated, or at least not as well as the heater, it’ll shed that heat rather quickly and have the heater calling for heat more often. The trap lowers the highest point to much closer to the unit.
Does that make sense? Lesse if I can fine a cite…
Here’s a differnt type of trap, the the idea is the same.
I can’t find a picture of the one I was trying to explain, but it looks like an S trap from a drain (except it would flow in reverse).