Home Improvement

Any experience with open direct hydronic in floor heating?

By June 5, 2019 2 Comments

I’m building a 330 sq ft tiny home and considering in slab hydronic heating. I love the idea of on an on demand water heater (mounted outside means no sq. Ft. taken up) serving the dual purpose of domestic hot water and heating the home.

I am currently dealing with Radiantec as I like there DIY kits.

Anybody have experience with open direct systems and/or Radiantec??

I am a noob and first time home builder.


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  • ronocnikral says:

    You’ll need a “side arm” to heat the potable water in the house. The water being circulated to heat your 330 sq ft house, should, IMO, have some type of glycol in case of system failure and preventing further damage if there is a freeze. If you don’t think this is a risk (which is different than it actually being a risk), you can run just continually circulate hot water through the system and then have your fixtures take the hot water off the radiant heat system. I would also suggest that you’ll have large temp swing in such a small area if you take long hot showers.

  • fahrvergnuugen says:

    I diy’d my radiant. https://i.imgur.com/fCVnTOu.jpg

    I did not do the “open direct” approach Radiantec has – instead I bought a combi boiler: http://www.usa.ibcboiler.com/ibc-products/dc-series/

    Using a regular DHW heater for radiant could work in certain situations, but I think for my case it just made more sense to use a combination boiler that had a dedicated DHW circuit.

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