The VC did great during the cold weather around here. I started on wood, switched to pea coal, then when it got cold went to nut. I only got around 10 hours between tending times
when I was running nut. If I was pushing the stove I would add new coal about every 8 hours or so. Since Momma died I have kept the house much cooler. With her having cancer and hypothyrodism I had to keep the house in the upper 70's all the time. Now I keep it around 68 or so.
Now that the temps have moderated into the mid to upper 20's at night I have gone back to pea. Kinda like the pea size because I can get an easy 12 hours between tending and It burns right to ash. With the nut I got small clinkers and the bigger pieces of coal that after they where burned they retained their shape. They were burned all the way through but still in the same configuration as when I poured em in. I would have to hit em with a poker and smash em to get them small enough to go through the grates.
The best part of all this is no matter what size I get it's all the same price, $160 a ton, at bulk. At the yard I I can get it by the 5 gallon bucket for $3 a bucket. I go through a bucket a day on nut so during the cold weather ( single digit to upper teens ) I could heat the house on $15 a week plus maybe 10 gallons of oil. I bought it at $1.95 a gallon right after the 4th of July holiday so my total heating bill plus DHW runs about $35-40 a week.
I'll take it all day long.