How Heating Systems Heat A Room

Wall Radiators

(similar to baseboard heaters)

Forced Air

(Typical Furnace)


(Floor Heat)

* Radiant Slabs are all about thermal mass; Consider the 1/3 loss of thermal mass under hardwood flooring?

Radiant Slab Floor – Prepared For Installing Hardwood Floors

(Gypcrete – Lightweight Concrete)

Photo Example For Hardwood Flooring Location

What it takes to install Radiant Slab Heat

Prep-Work & Material not required when using a Warmboard

Additional Engineering

(This cost should remain the same unless you add the slab after engineering.)

Stronger, more expensive floor joist and support beams $???

(This cost could be substantial pending the final engineering.)

Add Blocking – Between studs (Every gap between studs) $???

(Additional 2 X 4’s needed,Additional Labor to install blocking.)

Build curbs at stair openings $???

(Additional 2 X 4’s needed, Additional Labor to install curbs.)

Build curbs at elevator shafts $???

(Additional 2 X 4’s needed, Additional Labor to install curbs.)

Install 2 X 4’s in areas where Hardwood Flooring is installed $???

(Additional 2 X 4’s needed, Additional Labor to install curbs.)

Seal all penetrations $???

(Gypcrete or lightweight concrete slurry will leak through any penetration into the level below.)

Slabs are never exactly level and/or consistent

Requires a much hotter water to provide heat.

(Staple up heating tube water temperature range 160˚ – 180˚ Gypcrete water temperature range 140˚-160˚)

Wood is an Insulator. (R-1 per/inch)

In the photo above, for every 32 square feet of sub-floor – 11.66 square feet or 1/3 of the thermal mass is lost. $???


Gypcrete or Lightweight Concrete

(Slab Heat)

Operating Water Temperature
140˚ – 160˚
Operating Water Temperature
10% -20% Comparitive Savings
Staple Up

(Underfloor heat tubing)

Operating Water Temperature 160˚ – 180˚


Warmboard -vs- Slab Floor