Propane DV stove/fireplace for off-the-grid cottage?

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rsplodge

Member
Apr 28, 2014
28
Ottawa, Ontario, Canada
Hi, I'm researching propane direct vent stoves/fireplaces for additional heat at my off-the-grid cottage for winter use. We live in Ottawa, Canada which has pretty cold winters. We do have a good wood stove at the cottage but it takes too long to heat the cottage up when we arrive on a winter weekend (could be 24hrs). The cottage is partly insulated but is a very open concept with a large double-glazed garage type opening window. So I'd like to add a propane heater/stove/fireplace. We do have a solar system there but I'd rather not have this running and providing AC to the stove while we are away. It could be 3 weeks between visits to the cottage. My questions:
1) Could I use a propane fireplace effectively for this application
2) Can I run some models without AC power, and if so, does it have to have a pilot light running all the time or can it use a piezo electric and run off of batteries?
3) Can I run it off a thermostat and have it set to quite a low temperature while we are away, say 10C (50F) or even lower? Will it just cycle on and off to maintain that temperature? Again without AC power
4) What do the minimum BTU input numbers mean? Is this referring to how low you can turn down the gas/propane whenever it is actually running? Do I care about that number? Presumably if it is on a thermostat it will just cycle on/off to maintain the temperature I set.
5) Are there any units or add-ons that would allow remote turn on by SMS signaling or I guess maybe this is something I'd have to build myself. Not sure my cell service is dependable enough there anyhow for that.
6) Is there any advantage to getting a wall mounted propane heater instead of a propane fireplace
7) How important is a blower? Couldn't I get the same effect with a portable fan next to it, and then I could make sure it is an efficient DC fan not some likely less inefficient blower fan. I know from trying to use a pellet stove before that the fans can be quite a draw on my PV system.
8) Any particular models you would recommend for my application? I really like the look of the Jotul GF 370 as it is nice and skinny and would fit well in the space I'm considering.

Thanks in advance!
 

kobudo

Member
Sep 10, 2008
105
MN
We have a cottage in a somewhat remote area where winter temps often get to -30*F
In the winter we use a thermostat for each of our four units and set them at 50*F when we are gone.
We run two different types of direct vent units. In each bedroom we have a Hearthstone Tudor model.
https://manuals.fire-parts.com/aws-...or-8210-tudor_8120_manual-pdf.pdf?inline=true
They are free standing and take up very little floor space. They are maybe 12 years old. You can have the doors open or shut on them. I believe they are each about 15,000 BTUs. They do not need any type of blower.
In the living and bathroom areas we have a 30,000BTU Empire wall unit and a 15,000BTU Empire wall unit. They also do not need a blower
We do not have electricity at our cottage. We keep the pilots lights on all the time. It helps keep spider webs etc out of them in the summer time and helps keep condensation down so they don't get rusty.
 

ABMax24

Minister of Fire
Sep 18, 2019
1,226
Grande Prairie, Alberta, Canada
Choose your gas fireplace carefully, some are them really aren't very efficient. The government of Canada has or used to have a website listing the efficiencies of a lot of models, the one that came with my house is less than 60% efficient. The cool thing with mine though is it runs a constant pilot light and requires no electricity to operate, but I can run the blower if I so choose.

Propane usage is totally dependent on your cabins heat loss. If your heat requirement was say an average of 10,000BTU/hr you would be looking at 320 liters per month with a 95% efficient appliance, if it's 60% efficient you are looking at 510 liters per month. Note these heat loss numbers are just a guess, you could be lower than this or way higher, but just give an idea. The heat loss in my 2100sqft house averages 23,000btu/hr for January as a reference.
 

rsplodge

Member
Apr 28, 2014
28
Ottawa, Ontario, Canada
Thanks. Yes I understand the usage is totally dependent on the cabin's heat loss but I like getting some typical figures from people so thanks for sharing your numbers. Also I understand that BTU usage is approximately linearly related to the temperature difference too between outside and the indoor set point. I'm sure my heat loss is very high at night with this huge double-glazed garage/patio door, but then I get heat gain during the day from sun through that south facing window. I don't know what the average heat loss is at the moment of the cottage.
So to your math: 10KBTU/hr * 24hr * 30 days = 7200KBTU @ 23.6KBTU/litre = 305 litres @ 95% = 321 litres, @ 60% = 508 litres. Did I do that correctly?
What stove do you have btw?
 

ABMax24

Minister of Fire
Sep 18, 2019
1,226
Grande Prairie, Alberta, Canada
Thanks. Yes I understand the usage is totally dependent on the cabin's heat loss but I like getting some typical figures from people so thanks for sharing your numbers. Also I understand that BTU usage is approximately linearly related to the temperature difference too between outside and the indoor set point. I'm sure my heat loss is very high at night with this huge double-glazed garage/patio door, but then I get heat gain during the day from sun through that south facing window. I don't know what the average heat loss is at the moment of the cottage.
So to your math: 10KBTU/hr * 24hr * 30 days = 7200KBTU @ 23.6KBTU/litre = 305 litres @ 95% = 321 litres, @ 60% = 508 litres. Did I do that correctly?
What stove do you have btw?

Yes that's how I arrived at those numbers.

Mine's a 36" Empire model, American Hearth I believe. I wouldn't buy one of these again though, I've used it about fifty times now and either the gas valve or thermocouple is currently malfunctioning.
 

kobudo

Member
Sep 10, 2008
105
MN
In a 12 month period we typically have the (500) tank filled 3 times.
Each fill usually takes about 400 of propane so maybe 1200 per year.
Costs range from $1.90 at the lowest to $4.50 per gal depending on the year.
April-Oct we go through very, very little. Just pilot lights and using the stove, oven and on demand water heater.
Typically, we get filled in November, January and March/April.
 
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kobudo

Member
Sep 10, 2008
105
MN
In a 12 month period we typically have the (500) tank filled 3 times.
Each fill usually takes about 400 of propane so maybe 1200 per year.
Costs range from $1.90 at the lowest to $4.50 per gal depending on the year.
April-Oct we go through very, very little. Just pilot lights and using the stove, oven and on demand water heater.
Typically, we get filled in November, January and March/April.
SORRY, EACH FILL TAKES ABOUT 325 OF PROPANE SO MAYBE 950-1000 GAL PER YEAR.
 
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