Last year was my first year burning in my Jotul 600 Firelight. I burn 24/7 and many times the fire wil need to go 10-12 hrs before a new fuel load can be added. For the first couple of months I tried my hardest to fill the firebox and not have the wood touching the (glass). The coal bed was very limited after 10-12hrs. If I fill the firebox plum full (some wood touching the glass) I have an excellent coal bed when I come home. I burnt most of the winter like this and had no problems with cracked glass. When you load your stoves do you make it a point to keep the wood away from the glass? This particular stove you can load from the front or the side. I always load from the side to keep the mess to a minimum. Once a week I clean the glass, I noticed a slight white haze that developed over the burning season, I could not remove the haze regardless of the cleaner. Just curious if that's common?