Tankless Water Heaters for Domestic Hot Water

I'm interested in installling one of the new "Tankless" hot water heaters in my sunnyvale Eichler for domestic hot water, NOT FOR RADIANT HEAT. (I installed a new Teledyne-Laars boiler for radiant heat a few years ago which is working perfectly).

If anyone has any specific experience with one of these units in an Eichler, or can make a recommendation for an installer knowledgeable about both Eichlers and the tankless units, I'd appreciate a reply.

Thanks,
Andrew