Heatmaster SS GS Series

Easy for You

  • Less wood cutting – These high efficiency furnaces use up to 50% less wood than conventional furnaces, saving you time cutting and loading wood and cleaning ash.
  • Easy access hinged rear door – The insulated rear door is built with a unique hinge design which allows for easy access to the rear of the furnace and quick and easy removal of the door if required without the use of tools or hardware.
  • Safe easy-to-use dual firebox door latch – Our carefully designed latch catches the door so it doesn’t swing completely open and expose you to excessive heat.
  • Water Level Gauge –  That’s easy to read so you never have to worry about the status of the water
  • High Efficiency Heat Exchange Tubes – Our vertical heat exchange tubes keep ash and creosote from blocking the tube are also easy to clean.

An Outdoor Wood Furnace that’s Built to Last

  • 409 Stainless Steel – Titanium enhanced and corrosion resistant, it is the only product that can provide the right blend of longevity, heat transfer and other critical traits that meet the HeatMasterSS standard of excellence.
  • Heatmasterss warranty – We back each furnace with our best-in-industry Lifetime Limited Warranty which is twice as long as the leading mild steel competitor. It confirms our confidence in our products.
  • Rounded firebox – The rounded design gives the firebox more strength with fewer welds.
  • Draft Induction Fan – Draws air through the furnace to keep the airways clean.
  • ISO 9001 Certified – HeatMasterSS furnaces are built to the very highest manufacturing standards, employing top notch design and engineering.
  • Heavy duty multi-layer insulation – We feature a foil-backed insulation that won’t trap moisture, gives you high R values and has no seams for heat to escape.
  • Combustion Chamber – Our high efficiency chamber has a horseshoe refractory design to help create the cleanest, hottest burn.

G100S – Contact Don For Pricing

The new GS series continues the Heatmasterss tradition of rugged, easy to use outdoor wood furnaces. The GS is our basic model offering great features and a new low introductory price.

But, if you’re looking for a furnace that may be used indoors or out, and one that has even more features visit the G Series page.


Firebox (W” x L” x H”)19 x 20 x 30
Firebox Door (W” x H”)16 x 16
Water Capacity (US Gallons)90
Approximate BTUs120,000
Dimensions (W” x L” x H”)37.5 x 57 x 77
8 hour burn rate47,772 BTU/hr
8 hour efficiency (Lower heating value)81.50%
8 hour efficiency (Higher heating value)75.80%
Annual efficiency (Higher heating value)68%

G200S – Contact Don For Pricing

This is our  most popular size of furnace. The G200s is a workhorse capable of supplying heat to a home and small shop or one large building. As always, our furnaces can also heat domestic water, swimming pools, hot tubs, garages, and more. The GS series gives you basic features at a low introductory price but if your’e looking for more, visit the G series page for more information. 


Firebox (W” x L” x H”)28 x 30 x 36
Firebox Door (W” x H”)20 x 20
Water Capacity (US Gallons)195
Approximate BTUs232,000
Dimensions (W” x L” x H”)51.5 x 70 x 87.5
8 hour burn rate111,315 BTU/hr
8 hour efficiency (Lower heating value)85.0%
8 hour efficiency (Higher heating value)79.0%
Annual efficiency (Higher heating value)75%

G400S – Contact Don For Pricing

One of the largest furnaces available, the capacity of this unit makes it suitable for many large load applications. It’s capable of heating up to four applications at the same time, a home and large shop or a commercial sized shop. And because it’s a GS model it offers the basic features you need for a low introductory price.


Firebox (W” x L” x H”)30 x 42 x 40
Firebox Door (W” x H”)20 x 20
Water Capacity (US Gallons)260
Approximate BTUs340,000
Dimensions (W” x L” x H”)51 x 82 x 90
8 hour burn rate180,409 BTU/hr
8 hour efficiency (Lower heating value)80.50%
8 hour efficiency (Higher heating value)74.8%
Annual efficiency (Higher heating value)74.4%