The study focuses on a life cycle assessment of a wood-based residential building and evaluates the magnitude of individual construction components—foundations, flooring, peripheral wall, inner walls, ceiling, roof, windows, and doors—in terms of climate change; acidification; eutrophication; photochemical oxidation; depletion of abiotic elements and fossil fuels; and water scarcity categories within the system boundaries of the Product stage of the life cycle. The assessment was done using the SimaPro software and the ecoinvent database. The results pointed at the advantages of mass timber as a construction material and highlighted the significance in the type of insulation used. Foundations were found to bear the highest share of impact on photochemical oxidation reaching nearly 30% and depletion of fossil fuels accounting for about 25% of that impact. Peripheral wall was ranked the worst in terms of impact on acidification and eutrophication (more than 25% of both), depletion of elements (responsible for 50% of that impact), and had about 60% impact on water scarcity. After adding up carbon emissions and removals, the embodied impact of the whole construction on climate change was detected to be 8185.19 kg CO₂ eq emissions which corresponded with 57.08 kg CO₂ eq/m² of gross internal area. A negative carbon composition of the construction was also set.

The construction industry is facing an increased demand to adopt sustainable green building materials to minimize the carbon footprint. Hemp concrete is a green building material not only because of its low embodied carbon but also because of its ability to regulate heat and relative humidity. Its thermal characteristics are often viewed as favorable for reducing the energy used to heat or cool indoor buildings. The current research is focused on the properties of hemp concrete from Slovak manufacturers which can be effectively used in construction as a replacement for conventional building materials and can also be effectively applied in building renovations. The basic thermal properties of hemp concrete, i.e., specific heat capacity, thermal conductivity, effusivity, thermal diffusivity, and lag time, were determined. The determination of all properties is dependent on the knowledge of heat fluxes at the surface and the density of samples. The insulation ability was expressed with a thermal conductivity of 0.099 W·m⁻¹·K⁻¹. The accumulation was expressed with a specific heat of 1540 J·kg⁻¹·K⁻¹ and density of 322 kg·m⁻³ in the air environment temperature of 22 °C and relative humidity of 50%. To assess moisture properties, the moisture content and the speed of molecules during diffusion and lag time, based on the thickness of the hemp concrete samples, were measured. The speed of water molecules during diffusion in hemp concrete was 8.6 × 10⁻⁷ m·s⁻¹. The study shows that hemp concrete has interesting hydrothermal properties for use as an insulation layer in envelope structures. Thus, this material can be used effectively in the construction field in order to meet the requirements of the current standards, which aim to reduce energy and environmental impacts.

Renovating existing buildings is a key strategy for achieving the EU’s climate targets, as over 75% of the current building stock is energy inefficient. This study evaluates the environmental impacts of three façade renovation scenarios for an office building at the Technical University in Zvolen (Slovakia) using a life cycle assessment (LCA) approach. The aim is to quantify and compare these impacts based on material selection and its influence on sustainable construction. The analysis focuses on key environmental indicators, including global warming potential (GWP), abiotic depletion (ADE, ADF), ozone depletion (ODP), toxicity, acidification (AP), eutrophication potential (EP), and primary energy use (PERT, PENRT). The scenarios vary in the use of insulation materials (glass wool, wood fibre, mineral wool), façade finishes (cladding vs. render), and window types (aluminium vs. wood–aluminium). Uncertainty analysis identified GWP, AP, and ODP as robust decision-making categories, while toxicity-related results showed lower reliability. To support integrated and transparent comparison, a composite environmental index (CEI) was developed, aggregating characterisation, normalisation, and mass-based results into a single score. Scenario C–2, featuring an ETICS system with mineral wool insulation and wood–aluminium windows, achieved the lowest environmental impact across all categories. In contrast, scenarios with traditional cladding and aluminium windows showed significantly higher impacts, particularly in fossil fuel use and ecotoxicity. The findings underscore the decisive role of material selection in sustainable renovation and the need for a multi-criteria, context-sensitive approach aligned with architectural, functional, and regional priorities.

This paper presents an experimental evaluation of the thermal performance of a wood–aluminum window installed in a timber building exposed to real climatic conditions. The assessment is based on long-term in situ measurements of heat flux and temperature variations. The aim of the research was to determine the thermal transmittance of individual parts of the window assembly, analyze their dynamic thermal behavior, and identify critical areas in terms of heat losses. The results revealed a spatially heterogeneous distribution of heat fluxes through the window structure. The center of the glazing achieved values close to the declared U_g parameter, whereas the edge regions of the glazing and the window frame exhibited a significant increase compared with the declared values. The time-dependent analysis confirmed a distinct diurnal cycle of heat flux and a phase shift between the glazing and frame components. Furthermore, it was demonstrated that the accuracy of local U-value determination is significantly affected by the magnitude of the temperature difference, with the stability and repeatability of the calculated U-values improved at higher ΔT values, particularly above approximately 10–15 K. The findings highlight the need for detailed, spatially resolved assessment of window structures and emphasize the importance of experimental verification of their thermal performance under real conditions.