Hot water heater

I currently have an indirect HW heater. It seems very inefficient. Takes a lot of work for my gas furnace to maintain the HW. And it often runs out for long showers and baths. I was wondering if I should go electric or HW on demand. I hear that the HWOD is very efficient. Is this True? What are the cost difference on the units. I have a plumber in the family so I am not worried about the labor. Also if HWOD is the way to go, can you recommend some units? Where can one shop for these? What size would I need. I have 1 kitchen, 2 full Baths and 1 laundry rm.

Thanks
CT

How efficient is your boiler? The newest ones are over 90%. The best tankless system is less than that. Depending on the tank you have, you would be hard to beat an indirect. Now, not all indirects nor tankless systems are created equal. Adding a tankless would likely require an upgrade of your gas service - new line, meter, and various piping. The output would vary based on the volume of use and the incoming water temperature...in the winter some places, the incoming water approaches freezing and any heater has to work harder.

What size is the current indirect?

One way to get more out of your current heater is to set the temperature higher, and then, to protect yourself from getting scalded, put a tempering valve on the output to limit what comes out of the tap.

You may just need a larger indirect.

heater

If you are referring to an electric HWOD then forget about it. They are very demanding on electric power and you may not have the main panel adequate for it, and will definitely not have the necessary wire sizes.