Electrical engineer and Olney resident Vernon Tice obtained a patent a year ago for a chimney furnace heating system designed to send fireplace generated warm air throughout a house.

Now Tice, who is president of Advanced Heating Systems Inc. is waiting for the public to beat a path to the firm's Gaithersburg office.

"We've got the one system that's tied to a home's central heating system," he said. "Our fireplace home heating systems is used in conjunction with any forced hot air furnace as an auxiliary source of heat."

Tice made the first installation of his system in his own house and he said that showed him that the system is meant to be installed only in new houses.

"It really has to be installed with the original system for efficiency," he added. So far, the system has been installed in seven houses here; and eighth is in the construction stage.

One of the installations is in the new Goshem Estates home of Bruce Lewis, a fellow engineer who is vice president of ABS and full time marketing the system. Tice said that the average fireplace in a new house is built for $1,500 to $1,800. His system can be added for $1,200 more, he said, with an estimated payback period of two to seven years.

"It will depend on the size of the house, the amount of time the fireplace is used and the cost of the firewood," Tice said. He said the results are especially worthwhile if the homeowner has a good supply of free firewood or can find hardwood priced at $68 for 2 1/2 cords rather than the usual $65 a cord.

In the Lewis house, which has about 3,000 square feet, Tice said the system is capable of fully heating the dwelling until the outside temperature goes below 20 degrees.