ᐅ Price Differences Between Insulation Underlayment and Moisture Barrier?

Hello everyone,

I am currently looking for a suitable underlay with integrated moisture barrier for laminate flooring (0.8 cm (0.3 inches)). Since a total build-up height of 1 cm (0.4 inches) has been agreed upon with the screed installer, the thickness of the underlay/moisture barrier can only be about 0.2 cm (0.08 inches). During my research, I noticed significant price differences. Are there reasons for this? As an example, I checked "Bauhaus.Info". They have, for instance:

Underlay Aqua Stop Smart Limited (2mm)
15m² (161 ft²)
€26.85
Thermal resistance (R-value) = 0.057 m²·K/W
Water vapor permeability = 100
Impact sound reduction = 20

Underlay Pro Acoustic (2mm)
5m² (54 ft²)
€29.95
Thermal resistance = 0.01 m²·K/W
Water vapor permeability = 75
Impact sound reduction = 18

Underlay Expert Aquastop (2mm)
10m² (108 ft²)
€4.49
Thermal resistance = 0.038 m²·K/W
Water vapor permeability = 75
Impact sound reduction = 19

Underlay XPS Light (1.6mm) + Vapor Barrier Film (0.18mm)
20m² (215 ft²) and 10m² (108 ft²)
€0.99 + €1.29 = €2.28
Thermal resistance = 0.05 m²·K/W
Water vapor permeability = 150
Impact sound reduction = 18

If you buy the underlay and vapor barrier separately, you save the most, but both need to be installed by yourself. A combined package at €4.49 is still quite affordable. Other combined packages are significantly more expensive.

Is this price difference justified?

Impact sound insulation refers specifically to the insulation for the room below you. In an apartment, this is usually irrelevant. For the room itself, airborne sound is more important.

Now, the question is why use Aquastop or vapor barrier foil?

In my opinion, go with the most affordable option. They all basically do the same job.