At first glance, Tom Howard's house doesn't look like an energy saver.

It's too big (6,300 square feet of living space) and too exposed, a glass and wood structure sitting high on a ridge above the Middletown Valley, open to the prevailing winds.

But in fact Tom Howard's utility bills so far are about the same as they were in the 1,500-square-foot house he moved out of last spring... about the same as they are in the three-bedroom garden apartments The Artery Organization builds. Howard is senior vice president of the construction company.

"Everyone was saying the only way to cope with the energy crisis is to build smaller houses in the future," Howard said. "I wanted to show it wasn't the only way."

So what he did was design an elaborate system of energy-saving devices into the plan drawn for him by Jack Kerxton of CHK Architects/Planners of Silver spring -- a system that "to me was so simple, yet I couldn't explain it to mechanical engineers who did it every day."

The idea was to create a house that would run efficiently either on electricity, if he chose to use it, or on the wood-burning and solar devices he located throughout. At the end of November he hadn't yet turned on the electric heat, and he was estimating that utility bills for his family of five (including three daughters, ages 6 to 11) would run about $85 a month on an annual basis.

The idea was to create a house that would run efficiently either on electricity if he chose to use it, or on the wood burning and solar devices he located throughout. He didn't turn on the electric heat until Christmas and still isn't using it full time. Based on bills received so far utilities for his family of five (including three daughters ages 6 to 11) should run about $85 a month on an annual basis.

Aside from the highly visible pool, Howard's most obvious energy-saving innovation is the windmill that sits on a 40-foot tower outside the house. The $5,000 unit generates electricity at windspeeds of more than eight miles per hour.Any power not needed in the house feeds back into Potomac Edison Co.'s grid and the utility pays him for it. So far he hasn't made a fortune. Windspeeds are low during the summer and in his best months to date -- October and November -- the mill has produced about $20 worth of electricity. In December, icing created problems.

Essentially, the house works like this. To hold the temperature, the walls are insulated to R-30 and the ceilings to R-38. To collect heat, the upper and middle levels have soaring cathedral ceilings that culminate in a high point, from which heat is circulated by a decorative fan or, in summer, exhausted through a working skylight. To store excess heat and warm the lower level, water-filled tubes run beneath the slab in the basement.

Into this basic setup, Howard situated a number of energy-saving devices, many of which work together.