Batumi winters are mild (January average 7.8°C), but the city gets 140 rainy days a year and persistent maritime humidity (76-89%). The 'warm vs cold' choice isn't really about freezing — both systems keep wind and rain out. It's about whether the balcony becomes a sealed thermal envelope you can heat and live in year-round, or remains an outdoor-adjacent shelter for storage and casual use.
Cold glazing — the technical reality
Single-glazed (typically 4mm tempered), aluminum frame without thermal break, vented horizontal and vertical seams. The system stops wind and rain but doesn't seal hermetically — air exchange continues through micro-gaps. U-value 5-6 W/m²K (essentially no insulation). Inside temperature tracks outdoor temperature with about 2-3°C buffer. Cost: $135-180/m² installed. Lifecycle: 15-20 years on standard hardware, 25+ on anodized.
Warm glazing — the technical reality
Double-glazed (4-16-4mm or thicker) with argon fill, aluminum frame with thermal break (a continuous polyamide insulator separating inside and outside frame surfaces), sealed gaskets, anodized A4 stainless hardware. The balcony becomes a thermally separate room you can heat. U-value 1.4 W/m²K — comparable to a modern apartment window. Cost: $220-320/m² installed. Lifecycle: 30+ years.
What the U-value actually means
U-value measures heat transfer per square meter per degree of temperature difference. A cold-glazed balcony at U=5.6 loses ~5x more heat than a warm-glazed one. In Batumi's climate, that translates to: cold glazing makes the balcony function as an outdoor space; warm glazing makes it indoor. For 12 m² of glazing with a 10°C difference between inside and outside, cold loses ~672 W of heat continuously; warm loses ~168 W. Whether that matters depends on whether you want to heat the balcony.
Sound insulation — a related decision
Standard cold glazing attenuates ~22-25 dB. Standard warm glazing (double-glazed): 32-35 dB. Acoustic laminated warm glass: 40-45 dB. Batumi boulevard street noise reaches 70-75 dB at 5th floor. Cold = boulevard sounds like a busy street through the glass. Warm = boulevard sounds like a distant murmur. Acoustic laminated = boulevard becomes background hum. Sound matters more than thermal in our experience for owners overlooking busy streets.
The Batumi context — when each makes sense
Cold is right when: the balcony serves as storage, drying laundry, occasional summer use; you don't plan to heat it; budget is tight at Standard tier; the apartment already has good thermal envelope and balcony temperature isn't critical. Warm is right when: you want a real living room — coffee corner, reading nook, occasional workspace; you want the balcony to count as living square meters; you have sea view and want year-round access; you're STR/Booking renting and the balcony shows in listing photos. There's no middle option — semi-warm hybrid systems exist but compromise on both fronts.
Lifecycle and maintenance
Cold glazing maintenance: track cleaning every 6 months, gasket replacement every 5-7 years (~$30-50/m²). Lifecycle 15-20 years before profile fatigue or hardware failure on coastal exposure. Warm glazing: minimal maintenance — wipe-down monthly, gasket inspection annually (we include this on Premium). Sealed double-glazed units last 25-30 years before efficiency drops. The lifecycle gap is wider than the price gap suggests over 20 years.