Green Mountain 40 review

  • Active since 1995, is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.


New Member
Jul 19, 2020
Troy, NY
Hi Hearth Community,

I'm relatively new to the wood-burning world, so go easy on me.

I'm am in the process of a renovation and looking for a wood stove as the primary heat for our master bed/bath/dining/living/kitchen area, which is approximately 1200 sqft. I recently made a visit to a hearth store in VT and the sales rep was encouraging us toward the Hearthstone line, particularly the Green Mountain 40. He noted the 2020 EPA updates which meant that most of what he was selling he couldn't comment on the long-term (or even short term) reliability of the models in store. He talked up the hybrid tech with the secondary burn and the catalyst combustor needed to reduce the g/hr CO2 output to meet the new EPA standards.

I've seen some folks commenting on the stoves in this line in other threads and there seem to be some concerns about the long-term reliability of the new EPA compliant stoves in general, including the Green Mountain 40. Some of the particular concerns are as follows:

--> It has 2 steel cats which are positioned with their cells oriented vertically below the flue collar. Folks have noted that these will get clogged and or damaged easily. Indeed, the salesman noted that they would need to be cleaned twice a burning season to keep things clear. The manual states they should be inspected (but not removed unless a decreased performance is observed) at least three times per season. This seems like a bit of a pain but is not a deal-breaker in my mind. The cats are only warrentied for 2 year and replacements are between $130 and $160, depending on the year they fail.
--> There is no ashpan

I'm attracted to the following:

--> Low wall offset distance
--> Cast iron build
--> Efficiency and low C02 output
--> long burn time (20 hrs + on low with hardwood)
--> Aesthetics (big glass window, wood handles etc)

So are they any folks out there who've had one of these installed and can comment on it's real-world operability after a full season of burning?

We're located in upstate NY, near Albany.


Staff member
Nov 18, 2005
South Puget Sound, WA
Welcome. With the new EPA 2020 regs now in place there are many new stoves showing up on the market. It's too early to say how they will do over time. We saw a few reviews on the Green Mountain line of stoves last year. So far they are positive. If you want a more established line of cat stoves with good burn times, also look at Woodstock and Blaze King stoves. They have been on the market for years.
Here is a comparision posting that may be helpful.


Feeling the Heat
Feb 2, 2020
Madison, WI
I second taking a look at the Woodstock Soapstone line of stoves. Several of their stoves are the hybrid models just like the Green Mountain 40 but have been around much longer and so are more well known in the wood burning community. I own the Ideal Steel to heat my home and it heats the areas I need heated very well! I easily get 12 hr and longer burns on it using good dry hardwoods, and 8 hr burns on softwoods. The hybrid tech in the Woodstock stoves seems a good deal simpler than the Green Mountain stove (in regards to where the catalyst is located). And all Woodstock models have an ash pan option :)


New Member
Mar 15, 2021
Thanks, folks. Much appreciated.
Any update on what you went with and how it worked for you?
I am looking to possibly buy this stove for my 1,300 sq ft home and wondering how long it actually burns and how the maintenance is as well as anything else you may have learned about this stove or why you chose another. Thanks!


Feeling the Heat
Feb 2, 2021
Southern New England
I own a GM 40 and have had it for a season (about 3 cords burnt so far)

It’s a great stove and I would say buy with confidence! Fit and finish is among the best, in my opinion it’s the best looking stove out there, and it actually heats very well (heats my 1600 sf house through New England winter)

I have needed to clean the cats a few times, they work great until one day you go to engage them and it chokes the fire down.It takes about 8 minutes to clean them. You need to remove the baffle (it’s held in place with gravity) and then lightly brush the ash of the cats with a soft paint brush then bam the problem is cured. I will also sometimes hit them with a vacuum or a lightly with a computer duster to make sure they are completely clear.

you may see reports of smoke coming into the room when reloading, I only experience this if I eagerly swing open the door and even then it’s a tiny puff and you can barely smell it. If I open the door carefully I get zero smoke.

great stove! Let me know if you have any specific questions.


Feeling the Heat
Feb 2, 2021
Southern New England
A little inspiration! I frequently find my self staring into this stove and ignoring the TV