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Radiant Floor Heating/radiant heat new house soapstone and Prodex


Morgan I have a two part question. We are in the planning  stage.
1) We are considering purchasing a large Tulikivi soapstone fire-
  place to augment a in floor radiant heating system. In your
  opinion, does this sound reasonable on its merits. Also have
  you had any experience with Prodex as insulation between the
  floor joist?
2) My wife wants warm floors in the master bath year round. Is
  it possible to put an and electric heating element on top of
  the hydronic system  to use when you don't want to fire up
  the entire zone ?

Badger Radiant Designs never do this
Badger Radiant Designs  
Let's start with the snake oil i.e. Prodex. If the numerous misspelled words in their brochure are not enough to cause alarm you will want to avail yourself of the numerous source describing the lawsuits by States Attorney General against all sorts of Bubble Foil manufacturers concerning outrageous claims for R-Value and whatnot.

Whereas it may help reflect radiant heat if properly installed in a sunny climate, there are better ways and means to accomplish this. Goal. For cold climate and particularly when misapplied as a sub-slab insulation, bubble foil is worse than worthless.

See the attached picture of one of my own early experiments with bubble wrap. I'm ashamed.

Your wife wants what I have. In all but the warmest weather my bathroom floor is on. This is accomplished in various ways depending on the heat load of the bathroom, appliances therein, climate and ventilation strategy. A year-round radiant floor will usually constitute a micro-zone, meaning any heat source may be called on for relatively short, low-load cycling. The possible short-cycling of some heat sources can make such zones expensive to operate and hard on the equipment serving them,

Careful design is required. We often use sub-systems drawn from a domestic hot water heater to serve such zones, but first a comprehensive heating and cooling Manual 'J'.

Finally, to the soapstone stove with radiant floor heating.

My grandfather was a stonemason and I was privileged to work with him on a few jobs. He was, among other things a master fireplace builder. From him I learned to appreciate the feel of warm stone. Nothing like it really. In Europe the idea goes back as far as writing and many old solid fuel stone cooking and heating appliance are still in use.

Integrating soapstone or any massive fireplace or heat source to any modern home is tricky. First, combustion air should come from without since fresh inside (potential combustion) air will be sparse.

Second, the location of the wood burner has to be carefully chosen since you may not feel like burning wood in your favorite room every night. And if the high-mass, slow-output of the stove satisfies your radiant thermostat the floor may have a hard time catching up the other 20 hours a day you may not be around. This is not to say it can't be done or even that it shouldn't but rather that informed decisions have to be made as it concerns size, placement, operation and control.

All questions for your hydronics based HVAC designer.  

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Morgan M. Audetat


Radiant panel heating design, including floors and ceilings, European wall panels and snow melting for residential and light commercial buildings..............................................................-Master of Steam and Hot Water,City of Minneapolis....................................................--- Master Plumber, State of Minnesota...........


30 years..... Charter Board Member - Radiant Panel Association, former manufacturer of condensing boilers, former national distributor of radiant floor products, son and apprentice of mechanical & plumbing contractor. Current mechanical/plumbing contractor specializing in hydronic based, integrated HVAC systems. Radiant floor heating/cooling. Snow Melting. Condensing Boilers. Indirect water heaters. System design, consulting and technical training world-wide. Licensed contractor, designer, installer and consultant.

B.S. University WI 1981 CONTINUING EDUCATION: Viessmann Condensing boiler and Solar water heating certification 2010, N.D.S.U. Lead Worker RRP certification 2010, Knight condensing boiler certification 2009, Wrightsoft Manual J CAD certification 2009, RPA Designer & Installer Certification 2008, Nate Hydronic/Forced Air Certification 2008, Uponor/Wirsbo advanced design school certification 2007, Buderus Wall-hung certification 2007, Power Limited License (low voltage controls) 40 CE credits 2005, Basic Hydronic Certification IPEX & Northern Alberta Institute of Technology 1998, Charter Board Member - Radiant Panel Association 1994, Residential Off-Electric to Hydronic Conversion Heating School Canadian Hydronics Council 1994, B&G Little Red School House 1993, Rood Utilities (now Auburn Technical Institute) Oil Burner School 1993 ,Tekmar Controls residential and commercial 1993, Division Manager and Advanced Hydronic Seminar Instructor for the first Exclusively Hydronic Radiant Floor Distributor in the USA 1990, Hydronic Radiant Heating Association Workshop participant with Richard c. Bourne, PE spring 1988, Master Plumbing, Hydronic, Solar Course Red Rocks Community College 1987.

Awards and Honors
2009 System Showcase Award - Radiant Panel Association

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