Indirect versus tankless for DHW?

Gyro-Gearloose

I've had both and there is no comparison. The indirect is the way to go. On my tankless, I had to run the boiler very hot to have enough hot water capacity during a long shower, and that was with a 5 GPM coil. The indirect has a 41 gal tank and will sit there and make hot water all day long. You can take a 60 minute shower and the water will still be hot!! I love it. Because I no longer have the tankless, my boiler no longer maintains temperature and my oil consumption has gone down. More hot water and it costs less.

Tom S._3

Indirect vs tankless for domestic hot water?

I'm finding that a comparison between a tankless gas WH and an indirect WH off a gas boiler is difficult, even if you know the boiler! I'm leaning towards indirect based on the following: I've got a new Utica UBH 90/100 boiler, 90% afue. Venting a tankless would be difficult in my home, to say the least. Space is not a concern, either. Thoughts/opinions? Please chime in!

ALH_4

a few random thoughts

I like the indirect because it gives you a reserve of hot water. It also means the hot water is there immediately when you need it. If you want to draw 8 gpm for a short period, you can do it and get the temperature you want. It also keeps just one fuel-burning appliance in the home. Indirects are far less susceptible to water quality issues. Maintenance is almost non-existent with an indirect. Gas piping can be sized for the boiler only, and no additional venting is required.

Instantaneous water heaters have their place, but I am not sure single-family homes are a good application.

Mitch_4

I'd

> I'm finding that a comparison between a tankless

> gas WH and an indirect WH off a gas boiler is

> difficult, even if you know the boiler! I'm

> leaning towards indirect based on the following:

> I've got a new Utica UBH 90/100 boiler, 90% afue.

> Venting a tankless would be difficult in my home,

> to say the least. Space is not a concern, either.

> Thoughts/opinions? Please chime in!



go with the indirect and a timed priority control. The timed priority allows the heating to catch up after 30 minutes of DHW call so the house temp stays good, but will direct 100% of the boiler output to DHW.

Add an outdoor reset because the Utica is condensing, but not modulating. OR will vary the water temp, you can target 180 for DHW and really maximize savings.


Utica is part of ECR, so is ARGO which makes controls so the pairing should be good.

Mitch_4

I'd

go with the indirect and a timed priority control. The timed priority allows the heating to catch up after 30 minutes of DHW call so the house temp stays good, but will direct 100% of the boiler output to DHW.

Add an outdoor reset because the Utica is condensing, but not modulating. OR will vary the water temp, you can target 180 for DHW and really maximize savings.


Utica is part of ECR, so is ARGO which makes controls so the pairing should be good.

Brad White

Indirect

You betcha. Everyone I know that installed a tankless had some issue with it, from waiting for flow to inconsistent control (temperature fluctuations). To be fair, many of these were due to installing the tankless too far away from the points of use, but in the end the solution was to add storage. This of course defeated the purported advantage but gave abundant hot water at consistent temperature.

Had they installed an indirect in the first place they could have saved themselves a lot of aggravation.

Tom S._3

Thanks for everyone's input. I think my heater of choice right now is Amtrol's WHS-60 commercial Boilermate. It loses a whopping .4 degrees an hour, which won't cause me to lose any sleep. The idea of not needing additional (code compliant) venting is certainly appealing. Also, it's been about a year since I did my gravity system retrofit and I'm still recovering...