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UNHEAT®
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Minimal thickness.
Advanced thermal
insulation.

UNHEAT® is a coating for interior walls that helps reduce heat transfer and the energy needed to heat or cool your spaces.

See how it works

Helps slow heat transfer.
In both directions.

Its cured water-based acrylic dispersion film adds resistance to heat flow: λ = 0.0456 W/(m·K), measured under ASTM C518.

It helps reduce the heat coming in.

When it’s warmer outside than inside, heat tends to flow in.

01Outdoor heat
02Insulating coating
03Lower heating and cooling demand

Helps reduce the energy needed to cool the space.

In heat: transfer from outside to inside. The same vertical section of the material, with UNHEAT applied on the inner face. The amber arrows indicate the direction of heat. They do not represent a quantity or a measurement.
OUTSIDEWARM
INTERIOR
UNHEAT®Interior layer
Arrows show the direction of heat flow. Conceptual section, not to scale.

The white layer is UNHEAT®. Applied to the interior wall, it dries to form the insulating coating.

Explore thickness

Every millimetre
counts.

Adding thickness to a wall takes up floor space. A thin layer helps preserve it.

From 1 mm dry thickness

Greater thickness. Greater thermal resistance.

A dry thickness of 1 mm is the starting point. The required thickness depends on the wall and climate.

A house with UNHEAT in two climates: snow and desert outside, a comfortable environment inside

Compare the space taken up
by two thicknesses

A room measuring 4 × 3 m 12 m² before coating · applied to all four walls
1UNHEAT® dry thickness
2Reference thickness for comparison
50 mm
Adjust this example from 10 to 100 mm. Choose the total thickness you want to compare.
With UNHEAT®1 mm
4 m
3 m
Interior floor area 11,986 m²
UNHEAT® layer · 1 mm
Reference solution50 mm
4 m
3 m
Interior floor area 11,310 m²
Total thickness · 50 mm
Floor area taken up by the layer
With UNHEAT®
0,014 m²
Reference solution
0,690 m²
Enlarged detail of the UNHEAT® layer. Both floor plans use the same scale. At this scale, the layer is barely visible.
0,68 m²of floor space preserved
in this example.
Difference in floor space occupied by the selected thicknesses.
This compares space occupied, not equivalent insulation performance. The thickness of each solution must be specified for the project.
How it is calculated
We start from 12 m² of interior floor area.For a thickness e in metres, the remaining area is (4 − 2e) × (3 − 2e®The difference from 12 m² is the area taken up by the layer.The result compares the two occupied areas.The example shows UNHEAT at 1 mm against a 50 mm reference solution.

Thermal insulation
that’s easy to apply.

UNHEAT® is applied directly onto the prepared wall, like a paint, and leaves a smooth matte finish. It adds thermal insulation in new construction or when renovating an existing space.

UNHEAT being applied to an interior wall
Interior application · Illustrative visualization
New construction

Part of your new build.

Apply the coating to your interior walls at the thickness specified for your project.

Renovation

On the walls you already have.

Assess the existing surface and prepare it for the coating.

Beyond
insulation.

Insulates. Lets water vapor pass.

Water vapor can pass through UNHEAT®, allowing the wall to “breathe.”

Water vapour passes through the UNHEAT layer. Conceptual section of a wall with a white coating on its inner face. Three blue paths indicate vapour moving through the coating; they do not represent visible pores or air circulation.
Water vapor
UNHEAT®Interior layer
Illustrative section · The white layer is UNHEAT®.
What “breathable” means
It means it lets water vapour pass through.It is not the same as ventilating a room: indoor air is renewed by ventilation.

Class A fire performance.

Low smoke development in the coating’s reaction-to-fire test.

A wall with UNHEAT exposed to fire: the flame does not spread across the coating
FIRE PERFORMANCEClass A
Flame spread
and smoke developmentASTM E84
UNHEAT®Interior layer
Classification published in technical data sheet v4.0 · April 2026.
View test data
Flame spread FSI (Flame Spread Index)25Smoke generation SDI (Smoke Developed Index)0ASTM E84-23a · QAI Laboratories, United States · December 2024, as reported in technical data sheet v4.0.The smoke index does not measure toxicity.

Technical data

Specifications and guidance to plan your UNHEAT® application.

Minimum dry thickness1 mm · 1,000 µm
Thermal conductivity · 25 °C0.0456 W/(m·K) · ASTM C518
Thermal conductivity · 50 °C0.0508 W/(m·K) · ASTM C518
Coating typeWater-based acrylic dispersion
FinishMatte white
Infrared emissivity0.30 · ASTM E408
Dry to the touch30 min · at 25 °C / 50% RH
Full cure48 hours
Solids by volume70% ± 5%
PackagingPail · 11 kg

The v4.0 data sheet specifies a functional thickness of 1 to 3 mm. Values are typical; performance depends on application and project conditions.

Documentation for your project

Technical data sheet Original PDF

Safety data sheetIN PREPARATION

The Spanish safety data sheet is in preparation. Write to us at ventas@glasst.co and we will send it to you.

Before you apply.

01What does the dry finish look like?

UNHEAT cures white and matte. The data sheet declares it valid as a final interior finish with no additional layers; the result depends on substrate preparation and on the application.

02Is it applied like paint?

The data sheet authorises brush, roller or airless spray. Insulation, however, requires a uniform dry thickness: with a roller several coats may be needed. Follow the preparation and dilution instructions in the technical data sheet.

03How many degrees can it reduce?

Results depend on climate, surface, building system and applied thickness. These conditions must be assessed with the technical team to estimate performance for your project.

04Does it work in both hot and cold weather?

Yes. By helping reduce heat transfer, it can help limit heat entering in warm climates and heat escaping in cold climates.

Let’s define the
thickness for your
project.

Tell us where your project is and which wall you want to insulate. We’ll help you determine the thickness and application requirements.

View technical data sheet
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