The orphanage relied on electrical heaters, which probably had been turned up during a cold snap on Saturday, he said.

Heating can be performed using sunlight combined with electrical heaters.

Flames, sparks from electrical heaters, hot wires can all cause pet.

There were no smoke detectors in the house, which was heated by oil as well as at least the one electrical heater, officials said.

The process temperature is regulated by adjusting the power of the electrical heater.

Clothes, an electrical heater and a tea pot lined the one room that had signs of life.

The passive system made use of multilayer insulation blankets combined with electrical heaters.

The police said they did not know the cause of the blaze, but said it could have been started by an electrical heater.

"Either the electricity shorted out or the electrical heater was too close to something combustible."

"They came to me two nights ago and took my electrical heater; it was so cold in that basement it was terrible," he said.