746-492-7512 contactus@ecofirebox.org
Plymouth, Massachusetts(MA)

Absorb Store and Release

Two fundamental design differences between a traditional open-air fireplace and the eco firebox fireplace:

Combustion Efficiency

The Measurement of how well the fireplace burns the gasses created when burning wood and how well the fireplace burns the solid (the wood)

Heat Transfer Efficiency

The Measurement of how well the fireplace transfers the heat to the room and or house vs up the chimney

The Traditional Fireplace

Combustion Efficiency

The traditional fireplace cannot generate enough heat to burn the wood gasses emitted while burning the wood. It quickly sends the unburned gasses (carbon monoxide CO and hydrogen H) along with the majority of the heat right up the chimney. 

Heat Transfer Efficiency

What little heat is released back into the room is from “reflection” of the heated firebrick at the rear of the firebox.  Most, if not all, heat in the room ceases to exist once the fire extinguishes because the damper and chimney remain open for some time after the fire, allowing CO to escape, but pulling much of the house’s heat up the chimney with it.

At absolute best, a traditional fireplace’s efficiency is only 20%, most are in the single digits.

Above, a typical fireplace design, showing air and heat flow from the firebox, throat, smoke shelf, and chimney.

As a point of interest, perhaps the most efficient open fireplace designs are the Rumford and Rosin, both developed in the 18th century. The shape of their fireboxes are designed to reflect more heat back into the room. Though a significant improvement over the traditional fireplace, they’re still very inefficient (combustion and heat transfer) compared to a masonry heater like the eco firebox.

The Eco Firebox

Combustion Efficiency

The airtight eco firebox easily generates enough heat to burn the wood as well as the gasses emitted, resulting in a 97% combustion efficiency rating. 

Heat Transfer Efficiency

Once 97% of all gasses and solids are incinerated, the eco firebox sends the heat through a series of masonry baffles to absorb and store heat in its masonry walls before releasing residual heat and gasses to the chimney. The eco firebox continues to radiate this stored heat for 12 to 24 hours at 150 to 170 degrees Fahrenheit to your home after the fire is out, keeping temperatures within the home at even, comfortable temperatures.

Heating masonry material and using it as a heat store to radiate over a period of time is not a new concept, there’s evidence of similar designs as far back as 25 BC. The concept of the eco firebox heat store can be exemplified by the Roman hypocaust, which was used as an early form of central heat. The Romans sent hot flue-gasses through a maze of masonry walls and floors, absorbing and storing its heat before exhausting up a chimney.