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To the real estate editor: Costly errors are more difficult to prevent in a heated house than in an unheated one. Last winter I left my house heated, but the fuel tank went dry and I had a freeze-up. Cost: $1,500. The insurance company refused to honor my homeowners policy, saying I did not exercise "due diligence."

A few weeks later the house froze up again. The person who was supposed to observe a warning red light in my window which denoted a falling inside temperature had failed to see it. This time there was plenty of fuel oil but sediment in the tank, as a result of the earlier cutoff, had shut down the burner again. cost: $800.

I didn't even submit a claim to my insurance company.

Still later, a third freeze-up was narrowly averted when pipes in the coldest (northwest) corner of the house were superchilled, perhaps by someone leaving a garage door partly open even though the house was unoccupied.

So there are three reasons for leaving the heat off all winter from one man's experience in one winter. The location? New hampshire. A reader