The size of the hopper is the biggest indicator of how long your stove will burn on a single hopper full of pellets. However, we found that with the exception of the Enviro, the manufacturers of the stoves we tested exaggerated their hopper size. Hoppers are measured in how many pounds of pellets they can hold, and there are slight variations in the density and dimensions of pellets that could account for small differences in measurements. We found the lid to the Enviro to be very narrow, making it difficult to load the pellets. The height of the two Italian stoves could make it harder to fill than the lower stoves, particularly for an elderly person.
An optimal hopper size should be at least 50-55 lbs. The reasoning behind this is this, if your hopper is 40 lbs and a bag of pellets is 40 lbs, you can only add a full bag of pellets when the stove is completely empty. Additionally, if you get a batch of low density pellets (pellets that occupy more volume by weight) having that extra 15 or so pounds to work with allows the entire contents of a bag and then some to be added when refueling is needed.
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Figure 15. Englander hopper registering as out of pellets and
turns off during full hopper test, with 13oz still remaining.
Hoppers are measured by the amount or weight of pellets able to be loaded into the stove at one time. Many of the stoves would register that there were no pellets in the hopper but still had a small amount of pellets that hadn’t made it to the auger (i.e. pellets stuck on the sides or in crevices).
The Ravelli and the Piazzetta hoppers were measured when filled up to the metal screen inside their hoppers, as directed by the owner’s manuals. The other 4 stoves did not have screens inside their hoppers. The other stoves were filled the maximum amount of pellets able to fit that would still allow the hoppers to close.
Claimed hopper size was higher than actual hopper size for all of the stoves, with the exception of the Enviro, which claimed the exact hopper size that was measured (60lbs.). The largest difference in hopper sized was observed with the Harman, having a claimed size of 64.5 lbs. but an actual size of 56 lbs., based on the pellets that we had. Our pellets were average density, measured at 43 pounds per cubic foot.
Hopper size can be very important to consumers and hoppers that can fit at least 50 pounds allow you can refill them with an entire 40-pound bag before the stove goes out. Some consumers may think that a 40-pound hopper would be the ideal for 40-pound bags. But aside from manufacturers exaggerating hopper size, the stove would have to run out of pellets each time for a 40-pound hopper to be useful.