Quote:
Originally Posted by Drake
Please bare with me on what I have been seeing as the best tube size/spacing recommended in the 20+ yrs I have been following hydronic radiant flooring which I planned hopefully to use in my last major retirement home project. 3/4" pex on 12"cc was very popular, and even 7/8" is out there for in slab. I see and understand that there is great variability in details of maximizing performance in how radiant floor is being applied now. I understand also a contractors desire to stick with what they know and is proven for them, some innovate more readily than others, but almost all believe the knowledge they are working with is sound. So am I understanding that the present direction of maximizing the evenness and efficiency of the floor loops is minimizing the tube spacing? Like with insulation generally more is better. Is the tube dia. a major factor or disadvantage beyond the minimum bending ability of it? In other words in my case could I use 5/8 ID pex as if it was 1/2 in a 8-9" spacing if I can work out the return bends(which I can do as I have room to mushroom out 180's to 12" if needed) in a goal to do low temp heating in a high mass slab(which will be very well insulated)?
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Drake,
You are asking important and complex questions regarding maximization of efficiency, that involve multiple variables.
I don't believe that anyone on this forum, including people who have been in the trade for decades, can precisely answer these multiple-variant questions.
Why don't you use a radiant floor design computer modeling program? They are written expressly for the purpose of optimizing over multiple variables.
You can get a program that will give you exactly the information you seek.
I recommend a free program called
Radiant Works.
All you have to do is download it, spend an evening or two with it, and familiarizing yourself with it.
Then you can try all the variables you want, vary the slab thickness, vary the tubing diameter, vary the spacing, vary the house insulation, vary the window R-value, vary the water temperature, vary the water flow rate, vary the floor coverings, etc.
There is nothing you can imagine that it can not handle.
Why don't you just do that?
It is made for optimizing radiant installations while juggling exactly the variables you are agonizing over.
You should do this.
-AC