Well, a week went by and I have to say that the Blackstone brand do produce more heat than the Northern American Pellets i tried the week before. Yes, the window darkened much faster, but it was able to keep the room warmer than NAP. If I had to choose between the two, i would stay with Blackstone. Interesting observation was that at low setting (stall 1) the firepot seemed more lively with Blackstone than with NAP. I assume is due to the higher heat produced by the pellets. This week I'm giving Lignetics a try. Sorry no pics of the build up in the firepot this time, but it was not as huge as with NAP, but definitely some hole were plugged.