All three solutions produce heat in the same non energy efficient way. I don't buy the business about the position of the baseboard relative to the direction the cold air is coming in. I would stay with the baseboard as the cheapest solution since you already have the wiring there and apply the savings to fixing the door.

Thank you both for your advice.

Sina, as a quick follow-up: one of the reasons we've been hesitant to change the door is that we've been told that all doors and windows almost always act as a source of heat loss/cold ingress in a room. Our logic was that even if this door is old, it can't be that much worse than a modern door--any door is going to be the main heat-loss culprit and we'd still have to address the issue in the same location Does that make sense or are we overlooking something?

I think whoever told you that any door, regardless of age and quality, will be a significant source of heat loss. Sure, it will be (somewhat) less efficient than a properly insulated wall, but keep in mind that doors come in different types and quality. I had mine replaced two years ago, in the Montreal suburbs (Beloeil). I went with the highest quality I could afford, it cost me around $2,400 and even at -20C, the door itself barely feels less warm than the surrounding walls, and there is no draft, no matter how hard the wind blows. Standing right at the door, you don't feel less warm than in the rest of the house.

I would have a few door companies over for quotes. I am confident after changing the door, you won't need the heater at all.

"as a quick follow-up: one of the reasons we've been hesitant to change the door is that we've been told that all doors and windows almost always act as a source of heat loss/cold ingress in a room."

No, a modern door or window can be as efficient -- and even more efficient -- than the surrounding walls. I replaced my windows two years ago and when I place my hand over the window, if feels no colder than when I put my hand over the wall. It's not just that an efficient door can be costly; it can make the entire room less comfortable by generating air movement.

I replaced my entry door with a Provia Heritage fiberglass door which cost about $1500. You may want to get a quote for a replacement door before considering another heater.

Thank you everyone. This is totally new information to me. I could not have imagined that a wood and glass door would be as efficient or more efficient than the walls. Would have thought that the insulation in the walls alone would be almost impossible for a door to match in terms of heat retention. But I hear what you're saying and will look into a better door.

Thanks very much.

--AB

Play offense first.
If you can’t afford a new door then take the door trim off to check insulation around your current door. Spray foam is better than your traditional insulation so I would replace it while you have the trim off. I’d use non expanding spray foam so it doesn’t cause your door jams to bow like the expanding foam can do. Put plastic down to keep your floor clean or on any other area you want to protect when spraying foam in gap between door jam and stud frame.

Replace the door for crying out loud it is the source of the problem and no amount of extra heating will help that.

Thank you everyone. I really do appreciate--and take to heart--the advice to just replace the door. It's clearly wise counsel and I'm currently looking for doors.

But I also think the heart of the original question is being lost in the door-replacing zeal. Even if I do replace the door, I still need to find a way to heat that part of the kitchen. That door is on the kitchen's exposed wall, so whatever form of heat I ultimately place in the kitchen ought to be near that door and that wall. Right now I am just trying to find the most energy-efficient form of electric heat for the kitchen in that spot.

So, all things being equal (and assuming I get a nice new heat-tight door), what's the most thermodynamically efficient approach for that spot--toe kick, floor insert convection fan, or caddy-corner baseboard?

Thank you very much.

A B, all of the heaters are identical in efficiency. They all produce heat by passing electricity through a wire that heats up like a toaster.

However, if you are talking about a kickspace heater that is connected to your hot water heat, that would be the most efficient.