Thermal Resistance

Purpose. Energy-efficient insulating glass units for building envelope glazing — windows, curtain walls, facade and transparent structures where thermal performance is regulated by SP 50.13330.

Construction and properties. Heat retention is achieved by using glass with a low-emissivity coating (soft-coat "I" — GOST 31364-2014, or hard-coat "K" — GOST 30733-2014) and filling the cavity with an inert gas (argon). A single-chamber unit with one low-E pane and argon fill provides an equivalent thermal resistance R0 of approximately 0.55–0.65 m²·°C/W; a double-chamber unit — up to 0.80–0.95 m²·°C/W (indicative values, confirmed by the test report for the specific glazing formula).

Governing standards. GOST 24866-2014 "Sealed insulating glass units. Technical specifications" (complies with Russian national standard, mandatory for the Russian market); test method for thermal resistance — GOST 26602.1. Low-emissivity glass — GOST 31364-2014, GOST 30733-2014.

Points to note. The numerical R0 value is not fixed as a single requirement by GOST 24866-2014 — it is set by the building design and confirmed by the test report for the specific formula (glass thicknesses, cavity width, gas type and coating). The dew-point temperature of the IGU must not exceed −45 °C, or −55 °C for the frost-resistant version.