Insulated Concrete Masonry Unit (ICMU) vs. Insulated Concrete Form (ICF)

Insulated concrete block or insulated concrete masonry unit (ICMU) has the opposite insulation configuration as an Insulated concrete from (ICF).
APPLES vs. ORANGES Think: Concrete Sandwich vs. Styrofoam sandwich. An insulated concrete block (left) is not the same product as an Insulated Concrete Form (ICF) (right). An insulated concrete block is a concrete masonry unit (CMU) with a middle layer of (EPS) insulation. It may also be called an insulated concrete masonry unit (ICMU). ICMU's are manufactured and installed as masonry units. Insulated concrete blocks can have contiguous (unbroken) insulation that is not necessarily continuous insulation (zero thermal bridges). NRG Block is actually a CICMU, since it has continuous insulation with zero thermal bridges. Since thermal bridging in mass walls represents the greatest opportunity for energy loss, it is crucial to eliminate as many thermal bridges as possible. The Department of Energy and ASHRAE 's Advanced Energy Design Guides recognize continuous insulation external to thermal mass as the most energy efficient insulation configuration for mass walls in all climate zones, An Insulated Concrete Form (ICF) is a stay-in-place EPS (expanded polystyrene) form in the shape of a block assembled at the construction site and filled with concrete. Opposite of an ICMU, and ICF has styrofoam (EPS) on the outside, and poured concrete as a middle layer. Crucial to understand: While an ICF may be manufactured in a block shape and called an “ICF block,” that does not make it an insulated concrete block. PERFORMANCE DIFFERENCE: It's a common misconception that ICF's thermal performance derives from its thermal mass. It does not. Read about why not in this study, whose conclusions, based on a cold weather ICF application, state: "No thermal mass impact or higher effective insulation value was observed." NRG continuously insulated concrete masonry unit's (CICMU's) insulation placement is more energy efficient than an ICF's. Why? When thermal mass is exposed to a building's interior, it moderates the indoor air temperature. NRG's thermal mass does just that. Compare that to an ICF. An ICF places a layer of insulation between the thermal mass and the building interior, which greatly diminishes the effect of the thermal mass. Because the thermal mass effect in an ICF is minimized due its insulation configuration, an ICF requires more insulation to have the same thermal performance as an NRG block. See below for a more in depth explanation. With the adoption of all-electric HVAC systems, NRG's continuously insulated thermal mass, with its high heat capacity and long thermal lag time, enables demand shifting of electric heating and cooling to periods of off peak times and rates.

Here is what scientists say: Thermal Mass - Energy Savings Potential in Residential Buildings

J. Kosny, T. Petrie, D. Gawin, P. Childs, A Desjarlais, and J.Christian Buildings Technology Center, ORNL

ABSTRACT:

"In certain climates, massive building envelopes-such as masonry, concrete, earth, and insulating concrete forms (ICFs)-can be utilized as one of the simplest ways of reducing building heating and cooling loads. Very often such savings can be achieved in the design stage of the building and on a relatively low-cost basis. Such reductions in building envelope heat losses combined with optimized material configuration and the proper amount of thermal insulation in the building envelope help to reduce the building cooling and heating energy demands and building related CO2 emission into the atmosphere. Thermal mass effects occur in buildings containing walls, floors, and ceilings made of logs, heavy masonry, and concrete.

This data shows that the most effective wall assemblies were walls with thermal mass (concrete) being in good contact with the interior of the building (Interior thermal mass and CIC-Concrete Insulation Concrete). Walls where the insulation material is concentrated on the interior side (External mass) were the worst performing wall assemblies. Wall configurations with the concrete wall core and insulation placed on both sides of the wall (ICI- Insulation Concrete Insulation) performed slightly better than Extmass configurations. However, their performance was significantly worse than CIC and Intmass configurations. The ICI configuration can be used for approximate analysis of the very popular Insulated Concrete Forms (ICFs) constructions, since ICF walls consist of the internal concrete core placed between shells made of insulating foam." Please. Look at the science. And then act upon it. Let's talk about your next NRG project. Call or e-mail Marty Walters, General Manager NRG Insulated Block mjww@verizon.net (716)947-9298 9am-5pm EST