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Small Cabin Forum / General Forum / Water heater confusion!
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Hunterda98
Member
# Posted: 13 Oct 2014 10:34
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I have a newly built cottage in northern Ontario and would like to be able to visit in the winter time. I am really confused about what sort of water heater to get. I am on the electric grid but do not have propane service. To save space I don't want a large tank. Tankless is attractive but I worry that electric ones won't heat well since the lake water will be cold even in the summer. And gas ones are expensive and need costly venting. And I'd have to get propane service which I otherwise wouldn't need, though getting it would allow me to get a gas range which I'd like. So maybe a small electric tank in my crawl space. Can anyone guide me out of my confusion?

Just
Member
# Posted: 13 Oct 2014 12:13
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I have a 25 gallon 220 volt electric under counter . it has been plumed to drain in winter by opening 2 taps. Works well , 2 hot showers in a row .

bldginsp
Member
# Posted: 13 Oct 2014 15:51
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For very occasional use an electric like Just's is probably best for you. But if you use it a lot you'll start to feel the electric bill. You don't need propane service if you are willing to haul 20 lb propane bottles. Hot water heaters don't use a lot of propane, its heaters that eat it up. But then you got the flu issue. An exterior propane on demand water heater, which requires no flu, will freeze in the winter at night and be ruined. So it has to be an indoor model, requiring a proper flu. Sounds like more than you are willing to do.

Julie2Oregon
Member
# Posted: 13 Oct 2014 22:11
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What about this?
http://www.amazon.com/EZ-101-Tankless-Water-Heater/dp/B003327HDK/ref=pd_sim_sbs_auto_ 4?ie=UTF8&refRID=181WKMBQZX0VG4CHB6TY

bldginsp
Member
# Posted: 14 Oct 2014 08:24
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Julie- that's an outdoor unit, which means it exhausts straight out the top, with no flu. Cant use it indoors. If you leave it outdoors when there is freezing, the copper heater coils inside it will freeze and break and be ruined.

Some people use outdoor units inside their building, and let the exhaust gasses just go into the house, but that's a risky thing to do and I don't recommend it.

Julie2Oregon
Member
# Posted: 14 Oct 2014 14:22
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Oh, rats. I thought that "outdoor" meant that it was rugged enough for outdoor installation. I've seen optional winterization kits for some of them. I was considering the Aquah 12L outdoor propane water heater myself.

I guess I'll just have to get an indoor one and vent it. I like the fact that they use batteries for ignition and not electricity and you can run them on a simple barbecue-type propane tank with a regulator.

MtnDon
Member
# Posted: 14 Oct 2014 14:39
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A couple of points to remember.
1. rated temperature rise... that is how much water flow in GPM can the unit supply for a given temperature rise in the water. EZ has a chart online that illustrates this.

2. the rate of flow... many of these small tankless heaters do provide much of a flow rate unless the incoming water is not very cold. Many of these will not give a warm shower when the incoming water is from many wells. USA average ground water temperature map

bldginsp
Member
# Posted: 14 Oct 2014 15:34
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More points to remember
-many on demand water heaters require an electrical hookup, some operate off batteries, some have neither.
- some have winterizing kits with an electric heater to prevent freezing. Requires electrical hookup.
- some interior types use a B vent which is cheap, others use stainless steel which is expensive.

There is a lot of variation in theses things, make sure you know what you are getting.

I'm getting a Bosch 330 interior type that requires no electricity and uses a B vent

Julie2Oregon
Member
# Posted: 14 Oct 2014 21:19
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Bldginsp,
I read that there are some Bosch models that don't require electricity but I did a search and couldn't find one. Would you mind providing a link to yours?
Julie

bldginsp
Member
# Posted: 14 Oct 2014 22:14
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Google bosch 330. They have them on Azmazon, I think

Hunterda
Member
# Posted: 15 Oct 2014 08:20
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Thanks everyone for your ideas! What a great resource community is.

Julie, here is the Bosch that Bldginsp has in mind: http://www.amazon.com/Bosch-330-PN-LP-Tankless/dp/B0089U2OTI

Amazon also sells a slightly bigger model by Bosch, the 550. Both are indoor units, needing a vent. It was the one I was considering.

MtnDon: I am wary about buying an expensive unit only to discover it never really heats up the water enough.

Bldginsp: I've heard that during winter when the cabin is empty for weeks at a time the cold air will come down the vent and freeze the unit. Does the Bosch unit have a winterizing kit? Does it need one?

Just: I like the under the counter lowboy electric heater. Probably the way I will go.

bldginsp
Member
# Posted: 15 Oct 2014 09:02
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Hunterda- if you leave any on demand water heater where it will be frozen, inside or out, you must drain all the water out of it before it freezes. They trap water in the heater element, and when it freezes it expands and breaks the element. Some heaters have winterizing heater elements that supposedly keep them warm, but this requires elec, and what happens when the power goes out? The solution is to have compressed air available and blow out the water.

Some units have drain plugs that let you easily drain the heater element.

I don't know if the Bosch line has a winterizing kit, but I rather doubt it since they are made to be used without elec. But I could be wrong.

Here's a thread I started a long time ago with a bunch of info on water heaters, might be helpful;

http://www.small-cabin.com/forum/3_4393_0.html

Julie2Oregon
Member
# Posted: 15 Oct 2014 21:38
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That was a VERY helpful thread, bldginsp!!! Thank you!!! It seems that both of the indoor and outdoor propane water heaters have venting and air circulation needs.

Since I'm going to have a woodstove in a small cabin (320 sq. ft. with vaulted ceiling) -- and being in Oregon, it has to be EPA-certified so it will have to be a regular-sized model and not a mini (the camp-sized aren't certified), I'm wondering about which way to go.

I was already considering adding a sort of "dog house" utility room to the side of my cabin with a small door to access the greywater filtering system/plumbing stuff. There would be vents and insulation. Would it be feasible to make the "dog house" a bit bigger and put an outdoor propane tankless water heater in here? Would that provide enough protection so the components wouldn't freeze in the winter and enough air for it to operate efficiently?

bldginsp
Member
# Posted: 15 Oct 2014 22:18 - Edited by: bldginsp
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Julie- hard to say, but I'd say that if there is not a heat source in the utility room, and it is vented, it will freeze. Insulation won't help much if at all if there is no heat source and a free exchange of air with outside.

I plan to put a Bosch 330 in a sealed closet inside my 300 sq ft cabin (with vaulted ceiling). The sealed closet will have combustion air ducts to the outside for combustion air, but since the closet is inside the heated cabin it should stay well above freezing. At least that's the theory.

I suggest you do the same or similar. On demand heaters have to be protected from freezing, one way or the other. Just an off grid fact of life. Remember that all your plumbing needs to be freeze protected, not just the water heater. Busted pipes are a regular occurrence in freeze country in winter, at least, where people haven't taken adequate precaution

MtnDon
Member
# Posted: 16 Oct 2014 00:12
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I second those thoughts of bldginsp regarding the advisability of using a water heater meant for outdoor use, in an enclosed space. If the space is vented to allow exhaust and fresh intake air to freely pass in and out then it could get cold enough to freeze the water heater. The on-grid solution is that the manufacturers build in small electric heaters to prevent freezing. That won't work well off grid.

IF our cabin was a full time off grid residence I would ideally go with a propane fueled storage tank type water heater. Add extra insulation. Then augment it with a solar collector. We get enough sunshine to make that work so well that in summer propane use would be zero. I know two people who turn the propane off from spring through fall with such a setup. Propane only is needed in winter when the sun is lower in the sky.

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