You have heard one good post,now it is time for the bad. I had a BL 4044 for one season,was so elated to see that thing go down the road to the next sucker I can't even describe in words.
Started out with an Empyre 450, rated at 8000 square feet,did the job but liked it's wood,not a real specific measure,but took 2 wheelbarrow loads at 10:00 at night to last until 6:00 a.m when it was real cold.
P&M BL 4044, took 3 wheelbarrow loads at 10:00 at night,furnace would be down to 140 and screaming for more wood by 5:00 a.m.
Now Heatmaster MF 20000 E, 2 wheelbarrow loads at 8:00 at night,didn't have to worry about more wood before 10:00 or 11:00 next morning,even now into drier wood 1 wheelbarrow load of wood for a 12-14 hour burn.
In summary,first furnace did the job,just really hard on wood,second furnace,took even more wood,p.i.t.a to get ashes to go through the firebrick,had to makeshift a poker out of threaded rod,to which I would be breathing in ash dust from trying to clear the brick. Rory at the company told me I was burning the wrong type of wood ( imagine that,dry elm) ,loading too often,but what do you do when you need more heat?,must have too big a heat load on the furnace,yet the smaller rated Empyre did the job,and placing the wood in wrong,how do you figure that?
Now with my Heatmaster,doesn't matter what type of wood I toss in,how I toss it in,and the ashes are a fine powder that drops through the grates,about a 5 gallon pail full weekly,less than half the amount of the previous two furnaces.
It has been a cold winter,getting down in wood,but even my wife remarked if we still had the P@M we would have been out in the cold a long time ago