Current external temp is 23F with freezing fog. Mitsubishi heat pump is keeping the house at 70F without any trouble. Obviously it's not as efficient as it would be at 40F external temp, and is probably having to stop and run a defrost cycle here and there, but it's doing so and working fine. The new heat pumps really are awesome.
Redundancy with heating
- Thread starter TJOPT
- Start date
RV10flyer
Solar Wizard
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- Mar 8, 2021
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My Fujitsu 33SEER 9K was putting out 110°F supply air temperature at 11°F outside air temperature. It was 70°F inside. Running full speed, total amps: 8.4@240VAC.
eXodus
Solar Addict
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If it's really only a backup heat solution I would consider one of the Cheap Chinese Diesel Heaters.
You can get them in 5kw and 8KW and 12KW. They draw external air for combustion and vent back outside. Diesel Fuel stores long term pretty easy. The electric draw is minimal.
Ducting through the house might be a bit difficult since it's a single point heat source.
Otherwise - we are doing fine with the portal Radiator style heaters. They are not super efficient, but we have two of them and move them to the room we are in.
Yes and open floorplan sucks for energy efficiency, noise etc. My next house will have lots of walls and doors. Just heat or cool the space you are in.
You can get them in 5kw and 8KW and 12KW. They draw external air for combustion and vent back outside. Diesel Fuel stores long term pretty easy. The electric draw is minimal.
Ducting through the house might be a bit difficult since it's a single point heat source.
Otherwise - we are doing fine with the portal Radiator style heaters. They are not super efficient, but we have two of them and move them to the room we are in.
Yes and open floorplan sucks for energy efficiency, noise etc. My next house will have lots of walls and doors. Just heat or cool the space you are in.
12VoltInstalls
life passes by too quickly to not live in freedom
- I have a friend that had a heating service business for 20+ years.
- This discussion here stimulated my mind
- My propane RV furnace works fine (32k btu I think) and uses ~650Wh/day
A propane RV furnace though ‘inexpensive’ for electricity usage is maybe ~65% fuel efficient and has fan noise that generally doesn’t bother me but I’d prefer no noise.
The RV furnace as mentioned is 65% efficient whereas Matt mentioned the tankless water heaters are 95%+. So tankless is a gain/cost reduction of ~1/3 right there.
By sloughing excess solar my hot water would be “free” 8 months of the year; probably 6 months of the year I could just leave “on” the battery system with no concern.
There are low-amp 12VDC circulators that are about the same watts as the RV furnace or a tad less and they are much quieter. I would put radiant in the floors and one run of hydronic baseboard in the ‘living area’ and a short one in the bath and that ‘should’ provide the least costly propane BTUs possible.
While the BTU’s of living space input is a concern (because hydronic is less “quick” in distributing heat being convective; i calculated maybe 30%), the RV furnace duty cycle is <20% on average days (often 5-10 seconds/minute) whereas hydronic is constant input. So I believe the BTUs/hour exceed the RV furnace if comparing duty cycles.
If it’s ultra cold I can always fire up the forced-air RV furnace (which did fine during the -31*F night we had last winter and the -29*F low of the previous winter).
Longer term I’m going to have some form of wood-fired heating with hydronic because the shop I’ll do this summer will be ~1000SF with tubing in the concrete floor and 2000 gallons of super insulated hot water storage.
This discussion has been very inspiring imho
You have 31 acres of woods in Southern IL? I'll make you a deal, let me hunt there a couple days per year, and I will come and split or bring wood in exchange. I'm only 700 miles from you....... Not kidding.
65NW
New Member
+1 for wood stove.
The peace of mind it provides when its cold out is second to none. Even if its just a tertiary heat source I think its important to have.
Kuma makes a oil drip stove that uses no power and would work for this as well.
For secondary
Pellet stoves, I've seen some that draw a fair amount of power. Certainly during startup, the igniter is quite a load. I would set it to constant burn priority if you have a control for that (let's it overshoot temp more).
I get that pellets are cheap and continuous feed is nice, I just dont know how they make them so cheap. The embodied energy to chip and then compress them seems like it is quite high.
Here in Alaska they ship containers of pellets up from Oregon and Washington and thats cheaper than our local pellet mill from local birch. I dont know how, unless someone is getting a subsidy.
Toyotomi heaters (toyo stoves) are all over up here. They consume 400w on startup for about 3 minutes and then draw 30w to run on high. They also make hydronic hearers for domestic hot water as well as heating. Very reliable and in the mid 90s efficiency. No.1 oil stores for years at atmospheric pressure and is easy to handle and transport vs propane which is always trying to get out of expensive containers and has a lower specific energy.
The peace of mind it provides when its cold out is second to none. Even if its just a tertiary heat source I think its important to have.
Kuma makes a oil drip stove that uses no power and would work for this as well.
For secondary
Pellet stoves, I've seen some that draw a fair amount of power. Certainly during startup, the igniter is quite a load. I would set it to constant burn priority if you have a control for that (let's it overshoot temp more).
I get that pellets are cheap and continuous feed is nice, I just dont know how they make them so cheap. The embodied energy to chip and then compress them seems like it is quite high.
Here in Alaska they ship containers of pellets up from Oregon and Washington and thats cheaper than our local pellet mill from local birch. I dont know how, unless someone is getting a subsidy.
Toyotomi heaters (toyo stoves) are all over up here. They consume 400w on startup for about 3 minutes and then draw 30w to run on high. They also make hydronic hearers for domestic hot water as well as heating. Very reliable and in the mid 90s efficiency. No.1 oil stores for years at atmospheric pressure and is easy to handle and transport vs propane which is always trying to get out of expensive containers and has a lower specific energy.
65NW
New Member
I
I used one as primary heat in my cabin when my stove was in for maintenance and besides being loud and running through more fuel, it did the job.
For the price, I would get two and put them on a common fuel supply and battery.
As far as I know there is just a small and a large. The kW outputs are kind of meaningless. But they are cheap and they do work!
I used one as primary heat in my cabin when my stove was in for maintenance and besides being loud and running through more fuel, it did the job.
For the price, I would get two and put them on a common fuel supply and battery.
65NW
New Member
One thing I forgot to mention is I have a wood stove and a small Honda 2000iu I keep so I can do black start no mater what the temperature is.
Cold black start procedure (have done once at -25f)
1. Make fire, start warming up cabin. Put snow on stove so you'll have water for tea later.
2. Get Honda, remove cover and place by stove. (Its full of gas so keep watch on it.)
3. Start Honda, let warm up.
4. Take Honda and use 110v 12v victron charger to start charging 12v (aux) system.
5. Start diesel heater (powered by aux sys battery), wait for it to warm up main battery pack.
6. Use Honda to warm up main gen set.
7. When main batteries are warm and can take a charge, start main generator and restore power.
Cold black start procedure (have done once at -25f)
1. Make fire, start warming up cabin. Put snow on stove so you'll have water for tea later.
2. Get Honda, remove cover and place by stove. (Its full of gas so keep watch on it.)
3. Start Honda, let warm up.
4. Take Honda and use 110v 12v victron charger to start charging 12v (aux) system.
5. Start diesel heater (powered by aux sys battery), wait for it to warm up main battery pack.
6. Use Honda to warm up main gen set.
7. When main batteries are warm and can take a charge, start main generator and restore power.
