OTTAWA — The Ottawa Fire Department said now that the days are cold, you should be careful things don’t get too hot at your house. Fire Chief Jeff Carner said that nation-wide this new year, there have several fatal fires because of portable and electric heaters. Such heaters should never be left unattended and you should be careful to make sure the heaters aren’t too close to combustibles, he said. The U.S. Fire Administration said you should make sure portable heaters are clean and in good working order. The fire administration also says to be careful in using fireplaces and other open-flame sources and to ensure you install and check carbon monoxide detectors.