Slab on grade zoning

Hilly

I have a single 4000' slab on grab project to put together. I'm curious how much you guys like to zone on your systems? All floor covering will be eng. hardwood and/or laminate flooring. There's a third floor covering on tile in the three washrooms, mud room, entry but all 5 areas are all on opposite ends of the blueprint. Will the R-value differences for those areas necessitate a different avg temperature? Could the tiled portion just be it's own loop? Or will the difference in R-Valve from 1/4"thinset & 1/4"tile not be enough to worry about?

It looks like I can do this with aprox 15-17 loops to have comfortable distances. But staring at the print I can probably see this being split to 3 remote manifolds for convenience in piping. The house spans 80'x45' so one manifold in the mech. room would never not work.

I haven't crunched the numbers yet, but I'll be on the agenda tomorrow. But I'm looking close to 50K I think. It looks like electric will be the source of energy.

hot_rod

How is the building divided up? How will it be used?

I keep the two extra bedrooms and one bath in our home at 62- 64F unless we have guests, so the zoning makes sense for me.

You should be able to play with tube spacing to get all the same temperature requirements to simplify mix stations.

One rule of thumb is all zone temperatures within 10% of one another, no need to add additional mixed temperatures.

Hilly

Well HR here's another question. If you had all one temp and didn't requirement separate temperatures.
System is 50K Would you consider using one ALPHA pump and then actuators on your manifolds and just leave it at that for simplicity and zoning could be done a little or a lot by pairing your actuators together? Or even further, if you could divide your zones into separate manifolds would you consider just one ALPHA pump for the whole system and then a zone valve to control each manifold individually?

hot_rod

so simple math, 4000 sq. ft X 1.40 (9" on center" multiplier) would be 5600 feet of tube.

Maybe not all rooms need 9" OC, but I like to add tight spacing to keep supply temperatures as low as possible.

IF 250' loop that would be 22 loops

Most radiant manifolds go up to 12 or 13 loops, so two manifolds with an Alpha on each would be sweet. Leave a spare port per manifold for any add ons, towel bars, etc.

Use low current draw actuators and you could have an actuator per loop.

If one zone has a bunch of loops, put that on a separate circ and you could save a handful of actuators.

A simple system, no mixing, mod con on ODR and ECM delta P circ, sounds like a nice system, if it's doable.

SWEI

As Bob pointed out, design for one temperature if at all possible.

We zone for two reasons: Intermittent occupancies (guest wing, studio, etc.) and external heat gains (solar, woodstove, etc.) Put all the rooms with south facing windows on one zone and the rest of the house on the other.

Design is critical. Pay someone if you have to -- it's worth it.

Hilly

I ran out of highlighter. After I highlight the prospective 'zones' I will see what you guys think. I forgot about people mentioning in the past about keeping south or north separated. Thanks for bringing up again. You can read all you want once, but repetition and use are what help you retain that information. Thanks for chiming in guys.

Harvey Ramer

And of great importance; Each room shall have it's own loop or loops. Do not run individual loops in such a manner that they encompass more than room. By running individual loops per room, you will be able to adjust the flow rate, AKA/heat output, to each room and get by with less zoning.

Sorry, I just saw your name, You already know this but I will leave it up for other readers.

hot_rod

And insist on "as built" loop layout, pics and even a video of the loops before the pour.

No harm in over looping, even if you end up with only a few zones, at least you will have manual balance potential with plenty of loops.

Master bath for sure should be it's own zone.

SWEI

Nobody likes a cold bathroom. We design bathrooms for 4-5°F higher indoor air temps by default. This usually means 6" spacing when other rooms are at 9-12-15-18" and sometimes requires additional tubing in walls or ceilings. Do it right and they'll love you.