Electric baseboards draw electricity, but produce no heat
If 6 kW of electricity's being drawn, then a little over 20,000 BTUs of heat are being produced somewhere (6000 watts * 3.41 BTUs per watt). If they're not being produced at your baseboard heater, then they're being produced somewhere else between the breaker and the heater. You could have a mis-wired system that is dumping heat into a wall or something, causing a fire hazard. I would turn off the heat and call a licensed electrician if I were you.