Hearthstone Green Mountain 40
#18 in Wood stovesFull review
For a small to mid size home that wants long, clean catalytic burns and soapstone’s gentle heat in a compact stove.
Leisure Time $3,349 Lehman's $3,499$3,349
The Hearthstone Green Mountain 40 is the better stove overall, rated 3.3 to 2.6. The Hearthstone Green Mountain 40 leads on efficiency, warranty and emissions. The True North TN10 costs $1,744 less ($1,605 vs $3,349).
True North TN10
#35 in Wood stovesFull review
For a small room, cabin or shop that needs simple, clean wood heat on a tight budget.
The Torch Guys $1,605 Flame Authority $1,985.50$1,605
Prices were last checked October 31, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Hearthstone Green Mountain 40 for efficiency (79% EPA tested efficiency (HHV) vs 72.6% EPA tested efficiency (HHV)), warranty (limited lifetime warranty vs 3-year warranty) and emissions (1.1 g/h of smoke particles (EPA) vs 1.4 g/h of smoke particles (EPA)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every wood stoves stove; a clear win is highlighted. How we rank explains each one.
| Factor weight | Hearthstone Green Mountain 40 | True North TN10 |
|---|---|---|
| Overall rating | 3.3/5 | 2.6/5 |
| Efficiency 30% | 95 79% EPA tested efficiency (HHV) | 63 72.6% EPA tested efficiency (HHV) |
| Value 30% | 0 $139.54 per 1,000 BTU of EPA tested output ($3,349, 24,000 BTU) | 0 $91.19 per 1,000 BTU of EPA tested output ($1,605, 17,600 BTU) |
| Emissions 15% | 58 1.1 g/h of smoke particles (EPA) | 43 1.4 g/h of smoke particles (EPA) |
| Warranty 10% | 100 limited lifetime warranty | 22 3-year warranty |
| Convenience 15% | 35 takes 16 in logs, blower optional | 20 takes 14 in logs, blower optional |
Specifications
| Hearthstone Green Mountain 40 | True North TN10 | |
|---|---|---|
| EPA certification | ||
| EPA certified | Yes (2020 standard) | Yes (2020 standard) |
| Efficiency (HHV) | 79% | 72.6% |
| Emissions | 1.1 g/h | 1.4 g/h |
| Tested heat output | 14,000 to 24,000 BTU | 13,100 to 17,600 BTU |
| Heating | ||
| Fuel | Cord wood | Cord wood |
| Type | Freestanding | Freestanding |
| Advertised output | 40,000 BTU | 30,000 BTU |
| Heats up to | 1,400 sq ft | - |
| Catalytic | Yes | No |
| Blower | Optional | Optional |
| Thermostat | No | No |
| App control | No | No |
| Fuel | ||
| Firebox | 1.3 cu ft | 0.8 cu ft |
| Longest log | 16 in | 14 in |
| Power needed | None | None |
| Installation | ||
| Flue size | 6 in | 6 in |
| Mobile home approved | Yes | Yes |
| Safety listing | PFS | Intertek |
| Dimensions | 23.25 x 19.375 x 30.375 in (W x D x H) | 21.375 x 18.5 x 27.75 in (W x D x H) |
| Weight | 350 lb | - |
| Warranty | Limited lifetime | 3 years |