Compare F 500 V3 Oslo vs Green Mountain 60
Jøtul Oslo vs Green Mountain 60 Cast iron or a soapstone lining
Both use a catalyst alongside secondary air and both test at 78% to 79% HHV. The Oslo has the bigger firebox (2.41 against 2.03 cu ft) and more tested output, 38,804 against 33,576 BTU/hr at the top.
Where to buy: no retailer links on this page yet. Prices below are the makers' own figures on the date shown.
Short answer: Choose the Oslo for more tested output and 24-inch logs. Choose the Green Mountain 60 for a gentler, slower heat from its soapstone lining in a space that needs less peak output. Both are dealer-priced; we haven’t verified current prices.
EPA Certification Side by Side
| F 500 V3 Oslo | Green Mountain 60 | |
|---|---|---|
| Type | Hybrid wood stove | Hybrid wood stove |
| Tested output (BTU/hr) | 14,001–38,804 EPAchecked 2026-10-21 | 12,608–33,576 EPAchecked 2026-10-21 |
| Efficiency (HHV) | 78% | 79% |
| Particulate | 0.5 g/hr | 0.6 g/hr |
| Carbon monoxide | 0.5 g/min | 0.49 g/min |
| Firebox | 2.41 cu ft | 2.03 cu ft |
| Test fuel | Crib Wood | Crib Wood |
Maker Claims Side by Side
| F 500 V3 Oslo | Green Mountain 60 | |
|---|---|---|
| Advertised heat output | 70,000 BTU/hr maximum; 13,200–37,000 BTU/hr tested range sourcechecked 2026-10-21 | Up to 60,000 BTU (product page); "60,000 BTUs per hour of cordwood" (manual) sourcechecked 2026-10-21 |
| Heating area | Up to 2,300 sq ft sourcechecked 2026-10-21 | Up to 2,000 sq ft sourcechecked 2026-10-21 |
| Efficiency | HHV 78.40%, LHV 84.73% sourcechecked 2026-10-21 | 79% sourcechecked 2026-10-21 |
| Burn time | Up to 12 hours (manual); up to 10 hours (product page) sourcechecked 2026-10-21 | "HeatLife" 24 hours of heat sourcechecked 2026-10-21 |
| Log length | Up to 24 in sourcechecked 2026-10-21 | 18 in maximum sourcechecked 2026-10-21 |
| Flue | 6 in, top or rear sourcechecked 2026-10-21 | 6 in, top sourcechecked 2026-10-21 |
| Weight | 445 lb sourcechecked 2026-10-21 | 405 lb sourcechecked 2026-10-21 |
| Advertised ÷ tested max | 1.80× | 1.79× |
| Tested BTU/hr per advertised sq ft | 16.9 | 16.8 |
Where They Differ
Output and firebox. The Oslo’s 2.41 cu ft firebox tests at 14,001 to 38,804 BTU/hr; the Green Mountain 60’s 2.03 cu ft firebox tests at 12,608 to 33,576 BTU/hr. The Green Mountain turns down a little lower, the Oslo reaches about 5,000 BTU/hr higher.
Efficiency and emissions. Close enough to call even: 78% vs 79% HHV, 0.5 vs 0.6 g/hr, and 0.5 vs 0.49 g/min of carbon monoxide.
Build. The Oslo is cast iron at 445 lb. The Green Mountain 60 is a cast-iron stove lined with soapstone blocks, at 405 lb. HearthStone markets the stone for its slow, radiant heat after the fire dies down.
Logs. The Oslo takes logs up to 24 inches, the longest in our database. The Green Mountain 60 takes 18 inches.
Area claims. Jøtul says up to 2,300 sq ft; HearthStone says up to 2,000. Both work out to about 17 BTU/hr of tested output per square foot, so neither claim is more conservative than the other.
Version check. EPA also lists a Green Mountain 60-1 (model 8661) at 14,533 to 35,571 BTU/hr and 81% HHV. HearthStone’s product page shows model 8660; check the label on any stove you’re quoted.
Who Each One Suits
The Oslo suits a main living area in a mid-size house where you want a bit more top-end heat and you cut your own long wood. The Green Mountain 60 suits a smaller or better-insulated space, or anyone who prefers the even, radiant warmth of soapstone and doesn’t need the extra 5,000 BTU/hr.
Common Questions
Which one holds heat longer after the fire dies down?
HearthStone says the soapstone lining gives 24 hours of “HeatLife,” the time the stone keeps radiating, not a 24-hour burn. Jøtul doesn’t publish a comparable figure. Neither number comes from the EPA test.
Why do they both advertise 60,000 to 70,000 BTU?
Both are cordwood maximums. Jøtul’s manual says its 70,000 BTU/hr figure assumes “a more frequent re-fueling cycle than specified in the EPA High Heat Output test.” HearthStone’s manual calls its figure “60,000 BTUs per hour of cordwood.” The EPA maximums are 38,804 and 33,576 BTU/hr.
Does the Oslo have a bypass damper?
No. Jøtul’s Fusion design runs the catalyst without a bypass, so there’s no lever to open on reloading.
See the full stove table, the heating and fuel calculator or other comparisons.