Do you have a heavy-ish dining room chair you could place in front of it? Or two?

Also, does the heater really get too hot to the touch so that a person would get burned? If not, then I wouldn't worry too much about it.

Unfortunately it does become hot and he uses our dining room chairs as walkers, so they are not heavy enough to use to block it.

but does it really become hot enough to the touch that he could be burned? unless it's hot enough to cause a burn instantly (like a curling iron would be, for example), then you probably don't need to barricade it. if it would just feel hot, but not actually cause damage, then teach baby to not touch. you reach out your hand as if to touch it, then quickly withdraw your hand, saying "ouch! hot! it hurts. don't touch."

Yes, it becomes really hot.

What about mounting something like a milk crate to the wall around the heater?

We had a floor radiant system with our crawler ( hot metal all along the lower walls...everywhere) so we alternated between total supervision and blocking the heaters with the expanded version of this
http://www.amazon.com/North-States-Superyard-Gate-Play/dp/B00020L78M

eventually we had to move out.

Good luck!

Maybe if you bought a medicine cabinet; since they usually have those junky, thin wood backs and removable shelves, you should be able to get rid of those pieces and place it over the heater. As long as its heat resistant, it should work.

Can you buy some moulding from a hardware store and cut to size, making a 3-4 inch deep frame then staple a window screen to it? You could paint the moulding first, and perhaps mount it so that the deeper side is between the screen and wall. Fabric might be prettier, but would deflect more and provide more of a barrier to the heat flow.

How about a DIY radiator cover? This was the first hit on my search but it looks like there's no shortage of plans and options.

It would be helpful if I actually included the link.

http://www.thisoldhouse.com/toh/how-to/intro/0,,1582598,00.html

Thanks to everyone for the suggestions. I like the milk crate and moulding ideas. I actually had already checked out the "this old house" link previously and really liked it, but I'm sure my son would rip down anything that isn't affixed to the wall. Please keep them coming!

Maybe if you bought a medicine cabinet; since they usually have those junky, thin wood backs and removable shelves, you should be able to get rid of those pieces and place it over the heater. As long as its heat resistant, it should work.

Abercrombie And Fitch

Baby’s skin is far more sensitive than ours! Don’t rely on your skin as a gauge. If you do, use the wrist or underside of upper arms. If you have not found a solution yet, or if you want a better one. Check out fireplace screens. You can attach permanently and find at Home depot.
http://www.babyproofernewyork.com/

Baby Proofer NY

We also used a fireplace screen to keep our toddler away from a nasty old wall heater circa 1968 - which did indeed get very hot to the touch. It worked great and looked okay too.