I am looking for help selecting a heat source for a infloor heat system. The system is in a recent addition to my existing house. Currently the system consist of two loops, one in a walkout basement, 250' of pex in the concrete, the second in an entryway, 75' of pex, also in concrete. The house also has a forced air furnace, as primary.

Last year was the first year I used this system, and installed an electric hot water heater as the heat source. I planned to run this off peak, but the slab would not retain enough heat, to hold throughout the day. Running the electric hot water heater on peak as much as needed, proved to be costly. I have natural gas as an option, and would like to switch.

The walk out basement loop tends to cool quickly, therefore, I would like a heat source that can run almost continuously inputting only a little heat as needed. I also would like the flexibility to add additional zones to the original house in the future, possibly using warmboard or something similar.

I was looking at a Quietside, dual purpose unit with tankless water heat, available at the local Menards. However, I have second thoughts after reading some of the post, discussing the tankless heaters.

Looking for my most efficient, best option, any suggestions???????????? Thank You

Bradford White Combi 1.

I try to tell people the "off-peak" is on peak more often.

Thanks for the feedback, any reason for the recommendation. This model appears to be a dual purpose tank water heater. Wouldn't this be inefficient because of heating ~70 gallons a water, when a radiant heat system is only using a small portion?

From what I have researched, I have 3 options. Tankless water heater, a tank water heated, and a boiler. In each case these should be modulating so the proper exit temperature can be achieved. Pros or cons of any of these system?

Thanks again,
Jon

82% efficient and dual-purpose saving space and installation cost.

Made for the purpose unlike the tankless "water heater" that should not be used for space heating.

ModCon boilers rule (I specify and install them every day) but even a ModCon zealot can see that such small loads are best served by simpler and less demanding heat sources.

But hey, if you've done the research...

I must agree with Morgan. After all its not alot to heat with anything.

Don't forget its not like you need a 70 gal tank or high water temps to heat the space.

I'm floor warming 350 sqft. with an electric Ariston 5 gal water heater.


Gordy
Gordy

Thank you for all the feedback, it sounds like these tank water heaters designed for space heating are the way to go. A smaller tank, is a good point, heating less should require less fuel. Do you know if anyone makes a smaller, natural gas tank water heater, that is designed for infloor heating? I do not necessarily need a dual purpose, since my domestic water is running on a separate system.

On a separate note, I talked to a couple local HVAC guys, and surprisingly both are recommending wall hung units. Both are Quietside, and one happens to be dual purpose, with a separate heat exchanger for space heating, mfg claiming 90% efficiency. This is the unit I had looked at originally. I noticed the lowest hydronic setting on this unit is 122 degrees, which seems hot for infloor. I wonder why would these guys would be recommending the wall hung units?

Lots of options, and it is starting to get cold, I need to make a decision.

Thanks again,
Jon

122°F would be hot for many HRFs. You may consider one of the 7 ModCon wall-hung boilers that boast 95%+ AFUE.