HeatMaster G Series Wood Furnaces

HeatMaster G Series Wood Furnace Overview

The HeatMaster G Series is a gasification wood furnace approved for indoor and outdoor installation. The gasification process reduces wood consumption, and its low maintenance design allows easy loading and cleaning. It is available in water capacities of 100, 195 and 250 gallons and a heating capacity of up to 350,000 BTU. The unit is constructed of 409 stainless steel for greater heat transfer and tolerance and features heavy duty multi-layer insulation. An insulated hinged rear door provides easy access to the rear of the furnace, and a dual firebox door latch is designed for safety. The 2016 starting price of the G Series wood furnace is $8,495.00.

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Consumer Reviews of HeatMaster G Series


  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
  • #2 of 4 HeatMaster Wood Furnace
  • 91.89% of customers recommended

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HeatMaster G Series Wood Furnace Reviews

Showing 36-37 of 37 reviews

"Review of G400"

5.0 rating
Very Satisfied

I researched many different brands of stoves over the last two years, 409 stainless was a requirement as my first stove, a homebuilt Central Boiler knockoff was suffering from some serious corrosion problems. I had even started to collect parts to build my own gassifier. After doing an extensive Google search on Heatmaster SS and reading the reviews from other owners I decided to buy a stove from them rather than risk building one out of a material I hadn't had a lot of experience fabricating and welding before. Even though I had plenty of time to buy a conventional before the end of the year I still decided on a G Series as the appeal of burning less wood was very appealing, and burn less it does. I'm heating a 2800 square foot 1800's farm house with a lot of single pane wood frame windows that need changed out, and so far out of the exterior rooms we've remodeled everyone had voids in the walls where the blown-in cellulose didn't reach. The shop is a converted pole/cow barn with not even a vapor barrier under the cement let alone any insulation around the perimeter; it's insulated with the foil-bubble-foil insulation and still needs to be tightened up more. The G400 easily heats the house and with the below zero nights we've had lately I still keep the shop at 40-45 at night, and I can also run my snow melt as well which is 110' of sidewalk. My old stove couldn't do all three no matter how much wood was shoved in through the day and sometimes could barely handle two. Earlier in the year when we had 40-50's for daytime highs and just getting to freezing at night I was having a steel rack of wood (holds half a cord) last 14 days. Now with the highs in the single digits, lows below zero at night and a -20 windchill I still expect to get at least four days out of half a cord and maybe part of a fifth. At most I'm looking at 4 cords a month during the most bitter part of the winter. So far I've had zero problems with bridging or maintaining a coal bed. I'm burning Ash that was cut last winter, split then thrown in a pile. All is burning well even with the excessively wet summer we had here. I've also gone into the woods and cut dead ash, cherry and elm pole trees and have burnt those as well with no problems. Large pieces have been 12-14' diameter, just need to add enough smaller pieces to maintain a coal bed. All of it was under 25%, I've burnt some wetter stuff that was laying on the ground in the woods but works better if it's mixed with equal parts of dry wood. Work the cleaning handle on the side once a day then depending on how much wood has been run through it I clean the bottom every 4-7 days. So far, it takes less than five minutes to do weekly maintenance. The powered draft with the bypass door is an excellent feature. We eat breakfast at our local American Legion every Sunday morning, with my old one I either filled it before we left, then came in and changed clothes or put it off till we got home. With the G Series I can go out in my good clothes, fill the stove before we leave for breakfast and I've yet to have anyone mention that I smell like wood smoke. Overall I've been very satisfied with my purchase, so much so that I decided to also sell Heatmaster SS products.

Martin Lappin

North Liberty, IN

"Gasification furnace."

5.0 rating
Very Satisfied

Hello, New to the forum, I wanted to do a review for the people on the forum and also for readers that are just cruising through looking for good info. I purchased a HeatMaster SS G-200 back in August after doing a lot of research on many different brands that are out there. Looking at all materials used in the different units and how they hold up, I learned that mild steel, boiler plate, 304 stainless steel, cast iron, are not the materials that are the best. They all have problems with heat transfer, cracking, water leaks, rapid corrosion. The 409 stainless steel overcomes all that. After seeing one in operation at the Boonville, New York logging show, I was impressed with the quality and amount of stainless that is used in the units. I purchased one that was at the show and the dealer delivered it on his way home. Thank you Bob. I removed my old Marathon boiler which was way too small for my house and garage that I added. I Installed the G-200, in a few days it was up and running. Always comes up fast to high temperature, which is good for 200 gallons of water. Quick recovery! With dual inlet and outlet ports it was an easy hookup, one set to house one set to garage. Fired it up, pretty easy to do with the blower on. It smoked a little until it started to gasify, then it cleared up and just heat waves out the stack. I burned pine until mid November with no problems and plenty of heat on the cold nights. Switching over to hardwood in November. It has been warmer this winter than last. I have been getting about 20 hour burn time on the wood, just heating the house on 28*F nights. HeatMaster made it easy to clean the heat exchanger tubes with the external handle. And the smoke bypass pulls the smoke away from you while you are loading. Easy ash removal on the bottom, less than a minute to do, maybe twice a month. I am very happy with this unit and the support I have received not only from the dealer and distributor, Slimjim, but at the factory level also. They all will answer the phone and return your calls. Thank you HeatMaster SS for building a quality outside wood furnace. Definitely refer a friend to HeatMaster SS. Best regards, Smokeless in NY

B Earls

Saratoga, NY

Other G Series Reviews

Online comments regarding the G Series seem to be mostly positive. Most responses to a homeowner on outdoorwoodfurnaceinfo.com who was thinking of buying one were very positive and said that it is a great unit, though a couple did mention that gasification units require more care than conventional units.

G Series Warranty

The warranty for the HeatMaster G Series wood furnace is comprised of the following:

  • Lifetime Limited Workmanship and Corrosion Warranty

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