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Razer

Why are water heaters white? not black?

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Why are all the water heaters painted white Instead of black? In the US it wouldn't matter so much because many are in dark places, but my water heater is hit by sunlight all day long. If it was black instead of white, it would cost less to run. It is an electric water heater, but where it is, even on cold days that part of the flat is warm from all the sunlight. I'm just renting so I won't take a can of black spray paint to it, but I wish I could.

Edited by Razer

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Why are all the water heaters painted white Instead of black? In the US it wouldn't matter so much because many are in dark places, but my water heater is hit by sunlight all day long. If it was black instead of white, it would cost less to run. It is an electric water heater, but where it is, even on cold days that part of the flat is warm from all the sunlight. I'm just renting so I won't take a can of black spray paint to it, but I wish I could.

They're not all white. My aunt has an 80 Gallon one that is tan in color.

I think most if not all newer water heaters are insulated so I don't know that painting it black would do much. If it did, there would be black water heaters on the market.

I wouldn't worry too much about it......

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They're not all white. My aunt has an 80 Gallon one that is tan in color.

I think most if not all newer water heaters are insulated so I don't know that painting it black would do much. If it did, there would be black water heaters on the market.

I wouldn't worry too much about it......

The one I have is about the size of stuffed backpack, I don't think there is much if any insulation.

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Since its (i assume) metal, the sunlight hitting it probably does a little bit to help it along anyways, the color i cant imagine would help all that much.

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Since its (i assume) metal, the sunlight hitting it probably does a little bit to help it along anyways, the color i cant imagine would help all that much.

You would be surprised, I almost always wear a black t-shirt. It can be really cold outside, but that sun is non stop, I have to take the black t-shirt off or close the blinds, even though it is really cold outside.

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I guess its possible.

My point is though that the metal of the heater is going to conduct heat pretty well if there's no insultation,

could try wrapping some black paper or put one of your older shirts on it, see if that does anything.

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My water heater is sort of a blue/grey. I never thought much about the color of such things...perhaps it doesn't really matter all that much?

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My water heater is sort of a blue/grey. I never thought much about the color of such things...perhaps it doesn't really matter all that much?

Pretty much diddly squat. The energy savings would be negligible. Most people's water heaters don't see daylight.

All outdoor solar water heaters are, of course, black (which is where this train of thought is coming from I think) but, no. The savings might be in the penny range.

Edited by Likely Guy

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My old water heater was grey.white paint is cheaper

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Why are all the water heaters painted white Instead of black?

Problems with the tank are more visible against the white color.

Water leaks above or around the tank may lead to a rusty staining color over time, which is harder to notice if the tank is black.

I've seen tanks with the open flame burners under them, which due to draft problems, lead to the flame coming a bit up the side of the tank, which leaves a black sooty residue, which is much more noticeable on a white tank.

Also a white tank is easier to find by service personnel, whereas a black tank might be harder to find in a dark basement in the shadows.

Those are some of the reasons I could come up with, there are probably more. :)

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Edit: nevermind. :)

Edited by Likely Guy

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1. I don't think you'll find ANY 'non-instant' water heaters that don't use a very efficient layer of insulation. As it is very hard to make insulation *not* work both ways - which is what would be needed for your idea, designing the water heater to take in energy via it's surface is probably not possible with current materials.

2. If you have a tiny water heater, it probably does not store hot water, rather only heating on demand. In which case again, there would be little point. Thermodynamics engineers do this sort of work all the time - if making it black was significantly useful, they would have.

If you are still convinced it would be worthwhile, why not do an experiment and find out. You'll need to do your controls first, though, and unless it was on an isolated and monitored circuit, it would be hard to eliminate other variables... I'd be happy to help go through what you would need to do.

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Thanks for all the feedback, I'll probably mess around with a few ideas. Seems a shame not to try something, since it receives direct sunlight for almost the entire day, during winter, inside what is basically a solarium.

Edited by Razer

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2. If you have a tiny water heater, it probably does not store hot water, rather only heating on demand. In which case again, there would be little point. Thermodynamics engineers do this sort of work all the time - if making it black was significantly useful, they would have.

This is what I was going to say. :tu: From the simple description, I think the OP has an "instant" water heater, which does not store water, so I agree that adding heat to the device would not help. Maybe it might add a tiny, tiny bit, like a hundredth of a percentage points worth, which obviously is a worthless addition.

What would be better would pre-heating the water before it gets to the heater. That would save a lot of energy. This could be done with a solar system, or with coils that absorb heat from the room/house and add it to the incoming water.

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I remember seeing an outdoor solar water heater painted black, with a box surrounding it covered with aluminum foil to reflect the heat.

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get a can of spray paint, paint your heater, and tell us if it really works,.

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