Recommendation for DHW

jsavage

I currently have an 80-gallon electric hot water heater in a house I just purchased. I want to replace it because it’s very expensive to run here in New England and it’s 10 years old.

My previous house had a triangle tube 110 solo with a 35 or 40 gallon indirect HWH from Weil McLain. I never ran out of hot water, even when I used the 3/4” hot water taps on the outside of the house for extended periods of time.

My new house has a 4-year-old US Boiler/Burnham Independence IN12 steam boiler, which is a 300k BTU behemoth. It has dedicated tappings for hot water.

So my big question is if I should go with another indirect setup or if I should get an efficient tankless setup like the Takagi T-H3-DV-N?

I’m probably leaning toward indirect and was thinking of going with the Amtrol 42 Gallon tank based on reviews and performance statistics. Is that a good choice? Should I have a heat exchanger with two circulators or just add that when/if I ever add a hot water heating zone?

Any thoughts/recommendations on how I should proceed would be much appreciated.

Thanks!

John Ruhnke

I like the heat exchanger idea. You would need two circs. The water at the bottom of the boiler is a bit sludgy so you need something designed to handle that. If you could run potable water through the other end of the heat exchanger than you could run that to a separate storage tank. That would be a bit cheaper than an indirect. Though I think a good tankless water heater would save you some energy and fuel bills during the off season.

HVACNUT

If the boiler has a tankless coil, then an Aquabooster is a good alternative with a steam boiler IMO. It costs less. It's not nearly as invasive. And maintenance is minimal compared to an indirect with steam. Even with a wye strainer, it will periodically clog the plate HX and kill a circ or two.

gennady

If boiler has dhw coil then install mixing valve or storage tank, depending on your DHW load and money you want to spend. If no DHW coil is present, then go for indirect DHW water heater. I would not recommend separate gas fired water heater, it involves gas piping work, additional gas load and possible new gas meter, that’s a lot of activities with questionable ROI compared to DHW from boiler .

jsavage

Thank you all for your input. The boiler does not have a tankless coil, so I would need to heat the water with a heat exchanger at a minimum if I was using a storage tank.

This is the Amtrol indirect I was considering. It’s heat exchanger coil is removable for cleaning... I’m not sure what added advantage a separate heat exchanger gives over this setup, considering that the heat exchanger in the indirect is accessible.

HVACNUT

That's a fine tank. And the Independence water taps are about the steam return so that's a plus. You won't need a separate HX. Just pipe it according to Burnham specs.
P.S. Have fun removing the plugs from the boiler. You might need a torch and a breaker bar.

mattmia2

There are indirect tanks that can be heated with steam as well. That i think opens up some issues like keeping steam production and consumption matched.

I think if you heat it with the water in the jacket of the boiler through a hot water loop though the indirect you could control it to be more efficient when you are not making steam for heating, assuming you could keep it from condensing.

Conventional gas water heaters are really inefficient because of the need to have a hole up the middle of the tank. My conventional water heater would run every time you ran some water to wash your hands or rinse something of in the kitchen, my Superstore indirect runs 2-3 times a day.

Larry Weingarten

Hi, If you have a basement or other place that doesn’t get too cold, a heat pump water heater might be worth looking into. They do make some noise, so away from living areas is best.
Yours, Larry

jsavage

@HVACNUT Thank you for the tip about the plugs. Not that it will make it any easier, but it helps to know what I’m getting into.

@Larry Weingarten considering I have access to natural gas and electric in my area is particularly expensive, I think it’s neat to

@mattmia2 I agree. The difference in energy required for hot water vs steam is substantial. Going with a steam solution would exacerbate the off-season energy usage. The boiler requires about 20 mins to generate steam from dead stop, and once it generates steam, all of the radiators heat up!

My biggest priority is efficiency. On one hand, there will be a lot of times throughout the year where the boiler has hot water that’s not being used, on the other hand, the summer is not one of those times.

I think I’m going to go the indirect route and look at the energy usage. If it gets too high in the summer, I might add an on-demand heater as a secondary heat source.

Thank you all for your help!