In my home we use propane for our furnace. Eventually our plan is to buy/install a propane-run generator. Then we'll be self-sufficient heat-wise. The propane will provide the electricity to run the propane-burning furnace.

Of course that will only last as long as the tank (pretty big) or as long as we can get deliveries. Where I live the propane will probably last longer than burning wood would. (no wood to speak of on my small acrage "gentleman's" horse property.

Maybe you could get install a small propane furnace in-line with your current furnace - whatever it is (electric or natural gas), though I'm not sure how cost effective that would be.

Ken K.

I'm wondering if water might be a better medium in some cases than rocks or bricks. By weight, water has five times the heat capacity of granite, for instance. However, you are limited to boiling as an upper limit. If you used 70F as your lower limit at which the heat was no longer useful, you'd have to heat a pound of rock to almost 800 F to store the same energy as a pound of boiling water.

It does seem clear that a nalgene bottle filled with boiled water would make a better foot warmer for your sleeping bag than an 800 degree rock.

Actually, I do have a small wood stove, but I was wondering if I could make it do double-duty by having the normal fire going with rocks or bricks in it, then remove the bricks with fire tongs to a large SS pot (2 or 3 gallons), and moving the bucket to the other end of the house for warmth there.

But mainly it seemed like a good way for people who have the means to build a fire outdoors but not indoors to have some heat when the power goes off. My neighbors have a small baby and a pellet stove. Had our power gone off (we were lucky in the last WA outages), they could have used this method.

But a related question on safety: So I've got my pot of hot rocks or bricks... if I set three 2-hole concrete bricks in a triangle, with a regular oven rack setting on them on a vinyl floor, would that be safe enough, or would there still be a combustion issue below? (I know not to leave anything nearby.) How about carpeting below?

Sue

Hi
I read the same thing about 12 years ago and immediately had to try it out. It's amazing how well this works !
For people weary of exploding rocks, rest assured that ordinary red brick is safe to use. Because it is so porous any water present in the brick is free to check out any time it wants without building up any pressure during the heating process. Though it is not impossible a brick may crack after repeated use, it will not explode !
Ever heard of brick walls detonating in a housefire ? <img src="/images/graemlins/crazy.gif" alt="" />
I once used this trick in an emergency when there was a blackout at around 10.15 PM and it was freezing outside. As the temp inside started to drop I remembered this and fired up the bbq and grilled 8 red bricks, 4 at a time for a little over an hour (75 min. I think it was).
Hauled them inside in wire baskets and although it didn't heat up like a sauna and despite the fact that my home is not that well insulated it did keep the inside temp at a comfortable 18 degrees Celcius (64.4F) during the night till power was restored at around 05:30 AM.
Since I used a charcoal fire for this it may have been hotter than your regular wood fire but I'm not sure.... However I think I got excellent milage from the hotbrick-trick
Regards,
Pharaoh.

> fired up the bbq
Now that solves my fire in the neighborhood problem. Of course, my BBQ is propane-powered, but that just means I have to have a few hours' worth of fuel and some bricks! No bricks in my neighborhood.

Susan,
If you're speaking of large "cinder-blocks" (8"x8"x16" nominal), which will give you 8" of clearance, I would think that would be plenty of room to protect whatever flooring was beneath it, even carpeting. Espcially if you left a little space between the corners of the blocks where they met in your triangle formation. Vinyl flooring is pretty tuff and usually won;t mar even if you set a scorching-hot pan directly on it for a few seconds, so I would think it could handle quite a bit of radiant heat.

I'm thinking the biggest problem would be having one of the hot rocks roll off the rack and onto the flooring and, before you could pick it up, it might scorch something. Of course, you were probably planning to use a bucket of rocks on top of the grill, so that would solve that. Ok, I scrolled up and re-read.... you have a bucket of rocks.