Where to begin?

Hello all you permies!

I have a few questions and I hope you don't mind me dropping by to ask

The price per kilowatt hour here is 17.9 which is too high for my budget!
If it were just my wife & I, I could and would go without heat which isn't too much of an ordeal living in NC.

But since we have a newborn, we need to keep it nice and toasty. The only problem is the electric bill coming in at $4-500 dollars.

The floor of the room is hardwood and the walls are drywall.. it is fairly large and connects to a joint room.
I am wanting to build a Rocket mass bench heater in my home on the second floor and was wondering where I should begin?

Will the weight of the materials of the heater be too much of a load?
What sort of foundation is used?

Also,
What is the difference between an 8-inch and a 6-inch mass heater?

Any information or advice would be SUPER-appreciated!

The mass in "thermal mass" is heavy and dense to work. You would have to have significant shoring up of the structure to hold the mass. That said, I have seen a few people post pics of mass less systems. The downside is no long term heat storage. Have you considered a ground level stove and using floor vents to get the heat into the upper floors? This is how we are handling the situation in the home we are heating. We are putting multiple stoves in our basement on the south side of the house. Large vents in the floor above the stoves for heat to rise up through. on the north side of the house we are putting vents in the floor for cooler air to fall back down into the basement. This creates a convection loop. I have also seen it done were the stove is in the center of the home, with a large vent putting the heat into the center of the upper floors, with all of the down vents out at the perimeter on all sides of the home. As the air cools along the outer walls it falls back into the basement. These convection loops are a great way to structure air flow. They do have some downsides, they link rooms above and below and sound privacy can be an issue. It is easy to offset the vents so you can't see through them, but the sound passes through. They also tend to make cold and warm zones, sometimes in the same room. To many factors to predict exactly how a system will work with this kind of convection, but if done right, you can get heat through the whole house.

Unless you are living in very special circumstances, you'll need to comply with building codes. Some codes are irritating but most of them exist because of common errors that resulted in damage to the building due to water or FIRE. Seriously though, check it out early in the process.

Brandon, you could also do a bell, it holds heat for less time, but it's lighter. Tho, depending on the insulative properties of the bell material, you can regulate the speed at which the heat is released and the heat accumulation.

For example, cob will release heat slower than concrete, and concrete slower than metal. You can also do single bell, or double bell. (the barrel is somewhat a bell in certain conditions)

IIRC concrete will hold more heat than cob for the same thickness.

You could also check the half barrel system. http://donkey32.proboards.com/index.cgi?board=experiment&action=display&thread=560 It's another type of horizontal bell. Onto which you can put some mass.

The advantage of the bell is that heated gasses stay trapped on top. And the exhaust of the bell is on the bottom. Ok, they get diluted if you don't block the feed tube, but if you do, via movements of convection, the top stays hotter.

Besides that, i don't know about the states, but in France, where i live, a wooden floor has to resist to 300kg per square meter permanently. That provides with a bit or leaway for mass. Tho, not huge ammounts.