Those are rather unusual, and at only 450 watts, it wouldn't be able to heat much more than a small bathroom.
We live in Washington state where electric rates are reasonable, and we heat our entire house with electric wall heaters. We used the "Pic-a-Watt" heaters made by King Electric:
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We got ours at the local Lowes stores.
They're quiet, don't take up much space, heat our house nicely, and we can set the temperature in each room individually. I highly recommend them.
Anthony