Our off grid house has limited solar in the winter. I would rather not run a generator to run a furnace. We have a wood stove that will carry a lot of the bulk of the heating demand but I am older now and weary of feeding the beast 24/7. I have been thinking of a non-electric VENTED propane heater of some kind. Williams has some wall furnaces, Jotul and a number of other companies make some nice looking "gas stoves". At my folks camp they have a floor heater that has always kicked ass. Yet all of the non electric options look pretty inefficient compared to electric operated heaters like rinnai's and such. I doubt running a generator to get the extra efficiency on propane really makes sense. Anyone out there comment on what they are using and cost considerations for heaters not requiring power input?
Heat without electricity recommendations.
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Risky Rob
Solar Enthusiast
Running a generator to get extra efficiency on propane?
Can you run the electric component (ignition, blower motor) for propane heat from your solar inverter? There are catalytic propane heaters that use no electricity.
Can you run the electric component (ignition, blower motor) for propane heat from your solar inverter? There are catalytic propane heaters that use no electricity.
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When it comes to electric heating “watt is watts” it doesn’t matter what kind of element that is used. What may make some apparent difference is a good built in fan that distributes that heat better than say a radiator type just heating the corner. Probably your best best is a propane vented forced air heater(aka furnace). I have a Buddy heater that I used on a drafty 43’ houseboat. My biggest complaint with that thing was the low setting wasn’t long enough and a fan to move it around Lol.
You’re going want the most efficient propane one you can find. A small Diesel heater is also very efficient but a bit noisy.
You’re going want the most efficient propane one you can find. A small Diesel heater is also very efficient but a bit noisy.
Nevadablue
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YMMV…
I’ve used unvented wall mounted propane fired heaters for LOTS of years. I’m 75 and still alive. Absolutely no issues with the heaters except keeping them running. The thermocouples tend to fail. Other than that, NO issues.
YMMV…
I am currently using a wood stove and fireplace as our backup heat. I got several tons of coal from Utah and this stuff is wonderful. A mix of coal and wood burns nicely. I do use a grate for the coal, it works better that way, plus getting the ashes out is easier when using a grate.
I’ve used unvented wall mounted propane fired heaters for LOTS of years. I’m 75 and still alive. Absolutely no issues with the heaters except keeping them running. The thermocouples tend to fail. Other than that, NO issues.
YMMV…
I am currently using a wood stove and fireplace as our backup heat. I got several tons of coal from Utah and this stuff is wonderful. A mix of coal and wood burns nicely. I do use a grate for the coal, it works better that way, plus getting the ashes out is easier when using a grate.
In terms of LP heaters, in my current house we have a number of Rinnai wall furnaces. They run at supposedly around 80% efficiency. The thing is the larger unit draws about 115 watts. So it runs a fan and a vent fan and the electronics in it. Something like a williams non electric wall furnace works off simple convection like a wood stove. But they are only about 65% efficient... but use no electric. I notice the Rinnai, which is a nice unit, seems to rarely just shut off. It is always using juice adjusting the heat level all the time so it might be running on low, but still always running. Well if it is really running 24 hours a day in January that is 2700 watts. Assuming I do not have that available in the battery bank I would have to run the generator over an hour to replenish that. Now this is all hypothetical because I don't know how much propane I am going to use. Lets say it is $200 a month with the 65% efficient heater. So technically I should save about $30 a month going with the Rinnai in that scenario. Which is great but if I have to run the generator to supplement the electric that number goes south pretty quickly.......so back to the original question. Does anyone have knowledge of efficient vented heaters or furnaces that require no electric?
Kinda makes me think of thermal electric. One side hot other side cold when power is supplied, but they can also generate power if the sides have temperature differential. That power could drive a fan. A Stirling engine can harness the heat much more efficiently to move air. Funny that I can’t find such a vented forced air heater. You’d figure there’s a need for it for off grid.
OzSolar
Whatever you did, that's what you planned.
Of course one would be wise to make sure that every building envelope improvement that could be made was already made. If you are really feeding it 24/7 then you probably have some room for improvement because you'll gobble up a lot of propane (or wood or ?) with whatever solution you come up with.
Have you considered a mini-split? My "run of the mill low end" 1.5 ton mini split provides a lot heat for around 400-1200 watts of electricity depending on how cold it is outside.
I know you say don't have much sun but what about adding a few KW of PV? If you have the room it might be the better investment. Propane isn't getting any cheaper.
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LazyDragon
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Check around on Facebook or craigslist for some older propane heat stoves. You can get a nice looking enamel unit that is pleasant to look at for $500 or so. Make sure it is direct vent, as you already said. Preferably get one that includes vent pipe. That stuff is shockingly expensive nowdays. Most units will run without power (except for the blower fan). As someone already posted, the AC powered blower fans are a big problem. They are easily 100 watts and also loud. Instead, use a DC fan mounted behind or above the stove. On amazon, search for "Airblaze". They make units that are thermostat controlled for convenience, they are super quiet and only use 7 watts. I have two, one for my woodstove and one for propane. They make a huge difference in distributing the heat without sucking a lot of power.
The airblaze units are also great for summertime. Put them in the window and they move a lot of air for just a few watts. For awhile I used some Ryobi fans. They make a battery powered DC fan that also works on 120V AC. 5 watts. They're convenient, but the don't last as long as they should. I've had them die in just a few months of intermittent use. And they aren't cheap. The airblaze units are much better built.
Example, here's a nice unit for sale near me. $450. People are renovating and going with something else. This will look a lot nicer in your home, versus some utilitarian wall unit. Or go for the wall unit if space is a premium.
The airblaze units are also great for summertime. Put them in the window and they move a lot of air for just a few watts. For awhile I used some Ryobi fans. They make a battery powered DC fan that also works on 120V AC. 5 watts. They're convenient, but the don't last as long as they should. I've had them die in just a few months of intermittent use. And they aren't cheap. The airblaze units are much better built.
Example, here's a nice unit for sale near me. $450. People are renovating and going with something else. This will look a lot nicer in your home, versus some utilitarian wall unit. Or go for the wall unit if space is a premium.
Probably the best bet is that wood stove and a couple of some “heat powered fans” like they sell on Amazon to move the air.
Rednecktek
Solar Wizard
I'm a huge fan of the diesel "Parking Heaters" at my cabin. Ducting gets the heat to where I want, they heat up the place quick, sip diesel, and run on 12v which makes them solar friendly. I have 3 so far, 2 installed and 1 spare in a box that I can rotate out if it gets sooted up from running low loads for long periods.
I’ve eyeballed these things and wished I knew about the small ones years ago ( probably not as good as the current crop). I had a buddy heater in my boat and it worked but the odor when you came back in was nasty even though you had adequate ventilation. A yacht near me had a marine version and there’s no way you could sleep if you were tied up next to that huffer. I’m imagining these small units are quieter. Yes they use electricity but it couldn’t be much. I’d put it in a small fire proof weather enclosure just outside for safety and perhaps a stainless steel heat exchanger in the exhaust to heat water. The water would drain back out when not circulating to a tank in a basement.
LeoThomson
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Have you thought of using an electric blanket? I have one draped over back and the seat of my chair, it uses about 120W on high, 40W on low and even the low setting is enough to lower the thermostat by 5 degrees Celsius to what I would otherwise need.
The issue with high efficiency gas combustion is the need for the extra combustion blower to force the flue through the additional radiator.
Also of note is the higher efficiency collects condensation to be dealt with. Hydrocarbons produce an astonishing amount of water when operating.
Rednecktek
Solar Wizard
If you can handle the VERY Scottish voice, I recommend David McLuckie's YT channel. He plays around with those a lot and has done a couple different versions of water heating on it, plus some pretty cool experiments. They run about 40w once they're running but there is an initial 9-10a draw while it fires up for the glow plug. Really the noisiest part you have to deal with is the fuel pump clicking.
As a reference, last Feb it was -15F outside and 68F inside with just 1 unit running after we got the floor insulated. It ran full bore for a couple hours then just ramped itself down and basically idled all week. Between the two heaters I think we used about 10 gallons of diesel for the week.
Having the intake and exhaust piped outside you really don't need much more than a cheap metal tool box and some ductwork to mount it outside and get the house toasty warm.
BentleyJ
Solar Wizard
Note, they claim the gutter pipe is steel… I am not aware of any gutters made of steel… all are copper, or aluminum. Or plastic, of course…
Nevadablue
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Steel guttering is as common as aluminum or plastic.
Amerimax Home Products 2 in. x 3 in. x 10 ft. White Galvanized Steel Downspout 3201400120 - The Home Depot
The Amerimax Downspout features a galvanized-steel construction and baked-on white enamel finish for years of maintenance-free protection for walls and foundations. This downspout is compatible with 2
www.homedepot.com
This is a big annoyance I have that a lot of heating appliances like "high efficiency furnaces" only take into account the efficiency of burning the fuel and not deducting that "efficiency" with the electricity required to produce that high efficiency burn. Biggest offender of this I think is outdoor wood boilers.
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