Reading through this thread I'm as confused as Sloppy...These two units do seem almost identical. Both companies now have brochures and specs posted for these units.
www.polarfurnace.com and
www.portageandmainboilers.comVisually look at the outer shell similarities, the bends and proportions seem way beyond chance.
Polar G3: 75"Hx42"Wx78"L Firebox 14.0 cu ft Firebox L 27"(wood length)Door 15.5"x22" Weight 2,750lb, Water capacity 250, 200K BTU output, Heats 14,000 sq ft
EGR 250:74"Hx42"Wx68"L Firebox 12.7 cu ft Firebox L28" Door 15.0"x18" Weight 3,200lb, Water capacity 160, 250K BTU output, Heats 4K-6,000 sq ft
Again, look at the outer shell, the bends, chimney location, cut-a-ways and the specs. Seems way beyond coincidence. Sperling mfg plant and Piney mfg plant are only 95 miles apart
Both seem to have horizontal and vertical exchange tubes and the same exchanger cleaning system. The EGR probably gets the extra weight from refractory weight.
Polar G2 and G3 can be found on the February EPA Certified list
www.epa.gov/sites/production/files/2015-08/documents/hhcertifiedwood.pdf, while the EGR is not shown.
Not that it matters, but who is the real owner of this design and who is actually manufacturing these units is intriguing.
Polar G3 200,000 BTU output and heats 14,000 sq ft?
EGR 250 250,000 BTU output and heats 4,000-6,000 sq ft? Where do all these numbers come from? Or rather who makes them up?