Help define high mass

Brad White_198

Radiant or not, has nothing to do with high mass, low mass or Latin Mass for that matter.

Mass is a function, depending on the components or system side of these terms as I see them:

1. Construction Mass, the weight and specific heat of the building surface or component into which the radiant tubing is embedded. Concrete, LW concrete, Gypcrete, fall into this category, in relative descent.

Conversely, the staple-up systems, subfloor systems (Viega Climate Panel or Uponor Quick-Track being two nearly identical systems), are decidedly low mass.

Your described system would fall into the low-mass category by my estimation. Normal wood construction, no concrete and low water content being evident to me.

Warmboard engineered sub-floor is somewhere in-between.

2. System Mass, the weight or volume in water or thermal storage of the heating system itself. Radiant or not, the terms "high mass" and "low mass" must be qualified. They may take the form of, for high mass: Cast iron boilers, cast iron radiation, larger water volumes such as old gravity systems.

The low-mass side of these systems might include copper-fin boilers, most condensing boilers with low water content, lighter-weight radiation such as copper-aluminum fin-tube and convectors, home-run systems using PEX products, panel radiators, etc.

The hallmark of high mass is slower but usually steadier response over time due to stored energy. Low mass tends to be defined by faster response time but sometimes more volatile control issues (short cycling being one, requiring minimum flow rates being another).

My $0.02 anyway.

Brad

[Deleted User]

Help define high mass system

Are radiant floors considered high mass systems? Though I thought they were, I was recently told they weren't. Or is it applciation dependent? I have 2000 sqft of floor, 2 runs of pex per joist bay. thanks, jd