
That worked relatively well, although it was slow. I have since gotten a second maul, as well. When it comes to using the wood to generate heat, problem #2 was that the winter was very wet, with heavy rain December-March. The wood was fairly wet; I wasn't covering it very well initially. Problem #3 is that the chimney, visible in this post, is pretty short. It doesn't necessarily draft that well.
However, manual wood splitting was viable, if slow. I learned that if there were a lot of branches coming off the piece I was splitting, it disrupted the grain and splitting was harder. Also, some types of wood split more easily. I have a friend in the landscaping business who soon supplemented my wood supply with a lot of mixed pieces, but he warned that some was sweetgum, which has a reputation for not splitting well.
Some sweetgum pieces split easily, but others were fibrous and stringy, requiring a lot of effort to separate.
This spring, I had to have an oak tree taken down; it was dying and right next to the garage, and also within falling distance of the power lines and house. The big parts (large branches and main trunk) were left by the loggers. Some of those are as much as three feet in diameter; they'll have to be chainsawed (either cut with the grain or across) before splitting in any fashion.

Cost is a factor. Gas-powered ones are generally $1300+, while electric ones are roughly $250-$850; most are in the $200-$400 range. Ones like the manually-operated splitter mentioned above generally cost around $120-$150 but are frequently on sale for $100 or so.
I decided to give an electric one a try and settled on a 7-ton model.
So far, it seems to be working okay. it's definitely slow compared to a gas model (my one experience with those came a long time ago with a friend whose father used one to split a mountain of cottonwood in an hour). However, the wheelbarrow load shown below took about 10 minutes, which isn't bad.
There are some small-diameter sawed pine pieces at the top right; those came from a dead pine branch that fell into the driveway. The rest is mostly sweetgum with some hickory.
So far I haven't used it on anything bigger than the 10" recommended, but it is handling that size well. I do have some wood to split that is larger. Shown below is more sweetgum. Even though the sweetgum mostly showed the same characteristics described above, the wedge forces enough of a split to make it easy to separate the pieces.
As long as it doesn't break, it'll be very helpful. It's substantially better than my previous approach.