Should I recommend an indirect water heater (not an electric heater) to my friend with an old boiler w/underwhelming tankless coil?

[JamieRI]

A friend down the street has an old oil boiler with tankless water coil. She complains of poor hot water for showers.

She asked her plumber to replace her water heater, and "so far an electrician came and installed a circuit" which sounds like she is about to have an electric water heater installed. She took this photo for me:


(my friend's old system that works fine, but the tankless coil now delivers a poor shower experience)

Given what this energy calculator says, operating an electric vs oil fired indirect is double the cost, ie an extra $400 / year (in Maine anyway!)
https://www.efficiencymaine.com/at-home/water-heating-cost-comparison/

A few years ago I switched to natural gas, and my setup now looks like this:


(above is my newer system with indirect water holding tank)

She knows the boiler is old, but can't afford to replace it right now.

Electric rates are jumping in Rhode Island...
Would it be a good recommendation to have her plumber add another zone to drive a holding tank, vs install an electric heater?

thanks
Jamie

 

[Arctic trouble]

Hard to tell in the photo but appears to me if that blue handled valve to the right of the switch is open that could be part of the problem. It may be there and open to help temper the dhw, if so a thermostatic mixing valve should be installed instead. A couple more pictures would be helpful, that aquastat is hiding the important stuff. In my area electric is over .20 per kw for my family of 4 that was roughly $120 monthly just for the dhw. Swapped to a toyo oil fired on demand and consumption is between 5-8 gallons month.

 

[JamieRI]

Hard to tell in the photo but appears to me if that blue handled valve to the right of the switch is open that could be part of the problem. It may be there and open to help temper the dhw, if so a thermostatic mixing valve should be installed instead. A couple more pictures would be helpful, that aquastat is hiding the important stuff. In my area electric is over .20 per kw for my family of 4 that was roughly $120 monthly just for the dhw. Swapped to a toyo oil fired on demand and consumption is between 5-8 gallons month.

Thermostatic mixing valve should be required with tankless! It was a boiler guy who described how the coils scale up over a few decades and just don't transfer heat well, and how the acid-wash de-scaling is a big risk to the old copper tubing. This boiler is 50 years old, and replacing the coil is not what anyone seems interested in doing.
So, I just want to know if I am on good standing to push for something besides an electric heater. An oil fired heater would have to share a chimney with the boiler, and at my house, a natural gas water heater was out because the flue pipe diameter was insufficient.

 

[Arctic trouble]

You said money is tight and that she already has the electrical work done for an electric heater. I believe the least expensive indirect will be no less than $2000 installed. Seems to me a simple electric tank is the cheapest to install at this point and it can be improved upon down the road and turned into a sidearm off the boiler as the budget allows.