I am remodeling my kitchen and I currently have and 8ft hot water baseboard heater in the room. I need to put a cabinet where the baseboard heater is now. I want to use a kickspace hydronic heater under the kitchen sink in lieu of baseboard. There are several models of kickspace heaters and I can find BTU information on all of them, but I am not sure of the current baseboard heater output. I want to make sure I size the kickspace heater correctly. I may need to install two units.

Is there a rule of thumb to BTU's for fin tube base board heaters?

Any other input on the replacement of baseboard fin tube radiators with kickspace hydronic heater would be greatly appreciated.

Thanks for the help