Hydronic Radiant Water Temp

rockasawrus

I'm building a house in upstate NY, doing my design in LoopCAD.

1st Fl is slab on grade, with 1/2" pex on 9" centers (6" on perimeter) - installed and concrete poured.

I later decided I wanted to do underfloor heat-transfer plates for the 2nd floor apartment which will have engineered bamboo flooring - truss joists are 16" OC for the most part. However, I'm coming up with different water temps for each floor - 109F for 1st floor, and 129F for 2nd floor.

These seem high to me, but probably fine for concrete floor I assume. For the second floor, this seems like it will be too hot for the flooring.

Also, the second floor bathroom (top right), is under heated, not sure how I can fix this…

Any advice is appreciated!

hot_rod

your room loads seem high fir new construction? That high btu/ sq ft load is what drives the supply temperatures

I see would expect loads in the 20’s even the teens per sq ft?

A friend built this home above Utica NY , a few years back with average loads around 23 btu/ ft

Panel l radiators and an A2whp

Kaos

You need to get a better handle on your actual heat load, for that you need a proper Man J. Anything code min (2x6 construction with sub 3ACH@50PA) will be well under 20btu/sqft.

Once this is sorted, what you end up finding in new construction, the loads are low enough that the floor will never be warm, never mind hot, if you have 100% coverage. Getting a handle on the load will let you reduce the piping a fair bit.

I live with bamboo click over heated floor and has been nothing but trouble. The issue is it is dimensionally unstable and start pulling the floor apart in the winter time. Mine is solid, engineered would be better, but I would still watch unless the manufacturer specifically allows for heated floor.

hot_rod

For wood floor , low temperatures but also humidity control will keep the movement to a minimum

Engineered wood flooring works best with radiant . I used a brand that has all hardwood plys. The cheap brands with particle board or softwoods core tends to dent or damage easily.