We have a preview of a Hyprotherm boiler which you can watch below.

Most important reasons why we are the
BEST OUTDOOR WOOD FURNACE!

We custom build every best exterior outdoor furnace for you!

BURN TIMES

If your buildings are insulated with good windows and you use a dry seasoned hardwood,
your burn times are usually 12 to 24 hours depending on the temperature setting in your building.

Comes STANDARD with one heating hookup — expandable to FOUR total zones!
Perfect for heating your home AND a shop, garage, greenhouse, apartment, pool, hot tub, and much more.

Every Hyprotherm furnace comes with a high-quality pump that we preset to run continuously. This means you never have to worry about freeze-up, even in the coldest winters.

We use state-of-the-art insulation to hold heat inside the furnace where it belongs:

Firebox insulation: High-temperature Superwool Plus® blanket (by Morgan Thermal Ceramics). It’s binder-free, needled for strength, and rated for continuous temps up to 1832 °F  so it won’t burn out or break down over time.

Side walls & bottom: 3 inches of Knauf ET Blanket plus a ¼-inch Solar Guard reflective layer, for a combined R-23.1 insulation value.

Front & door: Lined with 2 inches of Morgan Superwool Blanket, delivering an impressive R-56.8 rating where most heat tries to escape.

Optional Cold Weather Package: Upgrades the entire furnace to Superwool insulation throughout, boosting total insulation up to R-68.4 and even up to R-88.2 with an extra-thick front/door package.

This advanced insulation design keeps your furnace hotter, your burn times longer, and your wood usage lower, even in the harshest winters.

Hyprotherm furnaces deliver consistently comfortable heat, often with water temperatures in the 160–180°F range — letting you burn less wood while staying warm.

This furnace features a massive, thick-steel rectangular firebox — typically 3/8″ or greater plate steel on the sides, with solid end caps — built to last under heavy, repeated burn cycles.

A forced-air blower feeds oxygen into the fire chamber, controlled by a thermostat that keeps your water temperature steady and efficient.

Inside, Hyprotherm uses round steel grates or rounded end caps to improve combustion airflow and reduce “dead zones” in the corners.

On top of that, the firebox is fully surrounded by water on all sides (top, bottom, front, back, and sides) — which maximizes heat transfer and helps maintain uniform heat.

BURNING COAL!

Great News!

We have a coal series furnace with a shaker grate!.  You can watch the outdoor coal furnace section at the top of this page.
We have had a customer burning coal in his furnace the past 2 winters!
He puts 8-10 shovels in, about to the bottom of the door, heaping in the middle about 9″.
This little bit will last him 12-16 hours he said!
He said that one of the advantages of coal are that it heats up faster.
He can come home late to a dead fire and the water cooled off and can have heat in 20 minutes!
The coal also lasts longer than wood. He often mixes wood, putting it on top of the coal and it works VERY well, he said.
He is heating a 3300 sq. ft house and a 1000 sq ft garage with 12 foot ceilings –
so an equivalent of 1500 sq. ft plus 3300 plus his hot water. 4800 sq. ft total.
The garage stays at 70 degrees even when it’s below 0 outside!
To top it all off, his furnace is 325 feet from his house!! He’s a happy camper…

Questions about Stainless Steel answered

Do you build with stainless steel?

No, we don’t build stainless for several really good reasons.
Our furnaces last longer than stainless with MANY furnaces still in use from day one!!
1. Mild steel transfers heat better than stainless does.
2. Stainless is a great sales feature, but little else, since most companies use cheap stainless, like a car’s exhaust system.
There are many grades of stainless out there.
3. Since stainless is so expensive, the fireboxes are made really thin.
Some are no thicker than the metal in a 55 gallon barrel or the thickness of a trailer fender!!
That’s why you see so many split and broken apart.
4. Stainless is more prone to stress cracks, so why use it?
5. Unless the stainless is retreated after welding, you’ve lost all of it’s properties through the heating of the metal.
And it’s being welded to mild steel anyway, so what’s the use?
Like I said, it’s a great sales feature but our high quality mild steel furnace heats better, doesn’t crack and split – and lasts longer!
If stainless was better, we’d surely be using it.

About us:

Innovative design. Real durability. Proven service.

• Years of Experience & U.S. Made — Hyprotherm Manufacturing LLC has been building outdoor wood & coal boilers and waterless furnaces in the United States since 1972. Every furnace is built in our facility, where we’ve kept evolving the designs, tooling, and steel-fabrication capabilities.

• Heavy Duty Construction — We use thick steel plate: standard fireboxes are 3/8″ thick, with an option for 1/2″ bottoms. The water-jacket bottoms are also built at the same heavy thickness where stress is highest.

• Minimal Welding, Fewer Failure Points — Our fireboxes are formed using a 430-ton press brake to create three of the sides in one piece before attaching the front and back end caps. That means fewer weld seams (where leaks often start) compared to many competitors.

• User-Friendly Features — Removable ash pans, large fuel doors (24″ × 24″ on many models), cast iron grates, off-the-shelf parts, no proprietary electronics where possible.

• Warranty & Customer Focus — Hyprotherm offers a 20-year on-site warranty. That means if something goes wrong, you don’t have to ship the furnace anywhere to get warranty work done. We back our product for real, and believe service is just as important as build quality.