Building a Rumford Fireplace!

Are you thinking of a fireplace in your home, or maybe have one and it simply does not provide heat!

Ever consider the Rumford?  Ever hear of a Rumford?

A Rumford is an old designed – designed to heat the home rather than the outside.  But the Rumford with the tall openings creates a beautiful and efficient fire that you and your family will love – and the shape of the opening will ensure you get the most heat from the fire as it burns.  Your friends and family will love. The unique shape ensures that you will get the most heat out of the wood you burn.

You see Count Rumford understood that the only really useful heat generated by any fireplace was the radiant heat. Any air that was heated by the fire simply went up the chimney, he therefore worked to design a fireplace with a large opening – which was fairly shallow – to reflect as much heat as possible back into the room.

The problem with the design is that a tall, wide shallow fireplace by design will tend to smoke, making the room uncomfortable. However, keep in mind that Rumford was a physicist and understood fluid dynamics – in fact he was way ahead of his time – in his design he essentially created a venture or nozzle which essentially will pull the smoke up through the throat into the receiving smoke chamber.  Because of this in the Rumford design the smoke is effectively pulled out the chimney instead of lingering and entering the room – an added benefit for those new to lighting a fireplace.

The problem is that is not the way masons were trained and many masons today, who are trained to build modern fireplace will have trouble believing a Rumford will draw – that is until they see it work.  You see the rules and Building Codes are different – in a modern fireplace the fireback is usually sloped forward pushing the gases from combustion toward the front, the incoming air from the room flows over the steel lintel and mixes with the heated gases, causing a turbulent smoky mixture.  Most masons, who while good at their job, do not understand fluid-dynamics and will tell you that you need to “cross over” or drop the lintel about 200 mm or so below the damper which will create a pocket for this turbulent smoke – or else there will be smoke coming out of the fireplace opening.

Because of the design, the opening into the chimney is only half as large, it takes more room for this turbulent air to get out.  It is a more efficient design, invented by a physicist.   The Rumford is more efficient, radiates more heat and wastes less heat to the outdoors.  Frankly, other than for aesthetic benefits one wonders why the modern fireplace design ever came into existence – it really was because an architect liked the looks – did not care about efficiency and designed around looks over performance.  It is rather unfortunate as our whole system now has grown accustomed to this design and feels there is no other that will work!  And a poor design it is – built on looks versus function – and with a Rumford you can actually have both!  Yes the Rumford – although not today considered traditional can be a beautiful and a functional fireplace which can heat the home efficiently.

 

 

 

Author: Chimney Sweep

WETT Certified Advanced Chimney Sweep - Loving It Every Day