You have an ACTUAL iron radiator inside your base sink cabinet? I am thinking you must be meaning something else? Otherwise, I would die to see a picture with the cabinet doors open! (And I might have an idea or two).

Not a great photo - but here is what it looks like under the sink. I'd love to hear any ideas. We are going to have to turn the heat on one of these days! :)

Oops, here is the photo

There may be some product out there which is designed to solve this problem but I sure haven't come across it.

I see three ways forward.

1.) Use the cabinet as a heat retaining box and then place some ductwork into the floor of the cabinet leading to your toe kick.

1a.) Put a fan into the loop, hooked to thermostat or to a manual switch.

2.) Call a sheet metal shop and have them build an enclosure around the radiator and then connect the ductwork to the enclosure, thus bypassing using your cabinet as a heatsink.

3.) Dig up your floor, lay down some piping, disconnect your radiator and channel the water into the floor piping.

Get a kick space heater.

Is this rad the only heat in your kitchen?

If not, can you please show us the others?

Did you do an addition, or is the square footage the same as before the remodel?

My initial idea would be to replace the sink cabinet doors with doors that had open vent panels in them, in oil rubbed bronze. You could very easily have a second set of doors to use for winter, and switch them out winter and summer.

Thanks for all the feedback. So this is original square footage (not an add on). It is the only radiator in the main kitchen space. There is a radiator in the breakfast area to the right, but I don't think that is going to be enough. We did think about a kick space heater, but it was going to be expensive with the installation and we were worried about how much white noise it would generate. I think some open vent panels in the doors would be neat, but I'm having trouble finding a product or an example of someone who has done it before.

Here is an article from This Old House website showing how to build a radiator cover. I think you can get some doors for the sink area from your cabinet company, but order them as though you would put glass in them (they would just have the frame in them with no center panel). Then add the metal fabric that has the punched holes in it to the door frames.

Here is a link that might be useful: this old house article

Ditto the kick space heater, it blows the heat out into the room. Even with venting, your current radiator is mostly going to be heating the bottom of your sink and the garbage disposal. Here's a picture of one of mine; the cut piece of the the cabinet bottom can be dropped back in so things can be stored there.

Don't know why my picture didn't show up, trying again.

If the room had been enlarged, or the radiator was inaccessible completely then I think the toe kick electric heater might be worth it. It will need a separate electric circuit, and they do use a fair amount of electricity to operate. Like running a hair dryer to heat your space basically.

But, since electric heat is expensive to run, and the radiator is already in place, I would recommend seeing if your heating needs are met with the radiator before adding the expense for supplemental electric heat. If need be, just take off the doors completely for now and see how the temperature is.

We have a kick space radiator that is a hot water radiator. It it is hooked up to our regular hot water heating system. The one in the previous picture looks like ours.

Ours is a Beacon Morris Twin-Flo, I think a K-84

Here is a link that might be useful: toe kick radiator

I would try replacing the door panels with caning first. (If you have cats, Lowe's sells metal decorative caning in the same patterns but you risk rust). The caning can be varnished, stained, dyed, or painted to match. You just need to have your front panels removed (easy job for a router with a flush trim bit) leaving just the frames. Then on the back route a small dado (groove) around the perimeter. The cane is then forced into the grove with spline. Trim the excess and you're all set.

One wouldn't think that you'd get enough heat with the radiator where it is, but I assume it's been in there for a while, so who knows? If the caning doesn't work, next year you'll have to move or replace the radiator. Is your system steam or hot water? If it's hot water Donaleen has a great suggestion if the retrofit isn't too problematic. Hopefully it's not too difficult to get to the existing radiator now that the cabinet has been installed around it.

With pex pipe now in common use, a radiator can be shoe horned in just about anyplace where it would make sense to have one, and a good salvage yard should have an abundance of sizes and shapes to choose from.

I work in the HVAC industry.

Radiators are sized by surface area and are designed to give off a particular amount of heat based on the heat transfer size of the surface area.

That is why I asked if the space had been enlarged or not. If this radiator was sufficient to heat the space before the remodel, then as long as the heat can escape into the space it should still be adequate.

If you change out to a different type of radiator, you should have an HVAC tech verify the heating load to make sure it is the correct size capacity.

Clarion's idea is nice. I am surprised no one has suggested replacing the drawer areas with the panels with decorative holes cut in them. These were common in older kitchens. I think they were to allow the undersink area to dry out or air out.

Some ideas:

Here is another consideration. How old is your house? Juliekcmo is correct that radiators are sized to the room, but they also typically assumed very little insulation (because they are mostly installed in older houses). Ergo, you may not even need it.

My 1929 house had a radiator in the kitchen at one time, but it was long gone by the time we got the house. The kitchen is often the warmest room in the house (if you are cooking).

You could just turn it off (close the valve(s) at the radiator) and see if it is needed.

Since the plumbing is coming up an exterior wall and the radiator is right under the sink I would be hesitant to disconnect the radiator. I bet those pipes are prone to freezing or at least were at one time. Does this happen to be the northern exposure?
It's also possible that some heat tape could solve this problem.