A Wood-burning furnace from a Down Easter

Maine is returning to its traditional fuel, wood, in response to the doubling of heating oil prices in the past two years (49 cents per gallon in 1978, 98 cents in 1980). So is much of the rest of northern New England. Fresh supplies of firewood are seen stacked in people's yards, especially in suburbs and rural areas.

Mainers have been adapting fireplaces, buying small wood stoves, and installing wood-burning furnaces. Local firewood is $40 to $60 a cord.

The determination of Mainers to avoid high fuel oil costs prompted Prof. Richard Hill of the University of Maine to develop an exceptionally efficient, virtually pollution-free wood-burning furnace that would be both economical and environmentally acceptable. Professor Hill's furnace burns its fuel at temperatures so high (2,000 F.) that practically all of the wood put in it is consumed. The heat produced is stored in a large water tank and less than 10 percent escapes up the chimney.

A prototype he built in 1978 caught the interest of John Dumont, the enterprising young founder of Dumont Industries in Monmouth, Maine. Mr. Dumont and his father, a master sheet metal mechanic, had set up shop in 1974 to make heat reclaimers for chimneys, solar collectors, and some items on subcontract. John Dumont, an engineer by training, is the driving force in the company. There are two other young engineers on the payroll. Mr. Dumont's father is shop foreman.

The firm was doing reasonably well when Mr. Dumont and Dr. Hill met at the 1978 meeting of the American Society of Mechanical Engineers. Professor Hill was impressed by engineering talent at Dumont Industries. John Dumont liked the concept of the Hill furnace and promptly began experimenting with the prototype. Mr. Dumont and his colleagues made several modifications aimed at improving the efficiency and reducing the cost of the furnace. Mr. Dumont has patented several devices on its version of Professor Hill's basic invention.

Mr. Dumont is producing a furnace suitable for average residential use (130, 000 B.t.u. per hour) that consumes six to eight cords of wood annually. The comparable fuel oil consumption is 1,200 to 1,400 gallons annually. In Maine the yearly saving would amount to be between $900 and $1,000. The installed price of the Dumont furnace is $5,500 to $6,500. Thus the "payback" period may be five to seven years at today's wood and fuel oil prices. A conventional wood-burning furnace of equivalent B.t.u. heat output costs $2,200 to $2,800, installed. An important feature of the Dumont furnace is that it burns 40 percent less wood than one like it of conventional design.

John Dumont dreams of a national market for his furnace. But he is a cautious and conscientious man. "Our biggest concern is to build a good working product that people can have confidence in, not an overnight profit."

His emphasis on quality over quick profits was established at the outset of development of the new furnace. Once he had the product ready for market, he set up a system to monitor the first 25 installations. Modifications were made on these early models, and the next batch of 175 units incorporated these improvements.

Monitoring the 25 test units convinced Mr. Dumont that a quality installation was of utmost importance to marketing success. "So we have chosen dealers with great care and we are constantly checking the units as they are installed," he said in a recent interview. In fact, a Dumont field man appeared at this writer's farm on the second day of a three-day installation job to check on the work and to add the latest modification.

The dealers, scattered across northern New England, are selected from established firms that have a local reputation for reliable heating equipment installations. Mr. Dumont tries to get dealers who will aggressively push his innovative product. Shopping for a wood-burning furnace last summer, this writer visited a nearby dealer and in the discussion of several conventional types I asked who handled "that new Hill furnace." It turned out he had just become a Dumont dealer and harbored some doubts that the furnace would sell at twice the price of the familiar models.

Most wood-burning furnaces pollute the air. not Professor Hill's. As soon as Dumont had its model ready for marketing, it shipped one to the Battelle Institute for air degradation tests under Environmental Protection Agency standards. The results showed no degradation from the unit. The Dumont furnace emits no visible smoke and practically no invisible pollutants. Subsequently the American Society of Mechanical Engineers issued Dumont its unqualified approval is usually required for heating equipment in public facilities.

Dumont, with a roster of 32 employees, is preparing to produce 850 to 1,000 of its furnaces annually, although John Dumont worries that the uncertain condition of the economy and especially high interest rates may block expansio n into a ready market.