The best large space heaters on our list use either an IR Quartz element and a fan to circulate the heated air, a ceramic element and a fan, or an oil-filled radiator, as with the DeLonghi TRD4, our #5 pick. An IR quartz element is good because it doesn’t dry out the air. It also transfers heat more efficiently than ceramics, though it may take a little longer to heat up. Radiator designs are quieter and typically take up less space.