602 Series Apartment — How Much Heat Are You Losing?
April 2, 2026 · 6 min read
The 602 series is one of the most common residential building types in Latvia. Built from the mid-1970s to early 1980s, these 9-story panel buildings can be found in Purvciems, Mežciems, Imanta, Pļavnieki, Ziepniekkalns, Vecmīlgrāvis, and Iļģuciems.
The load-bearing structures are made of claydite concrete (keramzītbetona) wall panels with reinforced concrete floor slabs. While the apartment layouts are considered comfortable, the thermal performance of these buildings is far below modern standards.
Sources: cityreal.lv, nopo.lv
Thermal performance of a typical 602 apartment
Let's estimate the thermal characteristics of a typical 2-room apartment (~50 m²) in a 602 series building, using the calculation method from EN ISO 6946:
| Element | Material | Thickness | Estimated U [W/(m²·K)] | LBN 002-19 max U |
|---|---|---|---|---|
| External walls | Claydite concrete | ~250 mm | ~1.8 | 0.23 |
| Floor slab | Reinforced concrete | ~220 mm | ~3.0 | 0.20 |
| Windows | Old double glass | — | ~2.8 | 1.10 |
Note: U-values are estimated using R = d/λ + surface resistances (EN ISO 6946). Claydite concrete λ ≈ 0.55 W/(m·K) per BS EN 12524. Actual values depend on panel condition and moisture content.
How does this compare to the standard?
Every element of a typical 602 series building exceeds the maximum permitted U-value set by LBN 002-19:
- Walls: ~1.8 vs 0.23 required — ~8× worse than the standard
- Floor: ~3.0 vs 0.20 required — ~15× worse
- Windows: ~2.8 vs 1.10 required — ~2.5× worse
What are the known problems?
According to research on Soviet-era apartment buildings in Latvia, common issues with 602 series buildings include:
- Freezing through external walls, particularly at end (gable) walls
- Degraded joint waterproofing between panels, causing moisture ingress
- Microscopic cracks in panels allowing air infiltration
- Limited renovation options due to structural panel design
Source: “Technical Condition of Soviet-Era Apartment Buildings in Latvia” (2023)
What can be done?
While individual apartment owners have limited options (you can replace windows), building-wide renovation is the most effective approach:
- External wall insulation (ETICS system) — ~150mm mineral wool or EPS can bring walls close to the LBN 002-19 standard
- Window replacement — modern triple-glazed windows (U ≈ 0.8) exceed the standard requirement
- Roof insulation — if the building has a flat roof, adding insulation on top is often the most cost-effective improvement
Estimate your apartment's heat loss
Calculate heat loss for your 602 series apartment
Select “Panel apartment (602 series)” preset for pre-filled values.
Open Heat Loss CalculatorData in this article is based on publicly available information about 602 series buildings from cityreal.lv and nopo.lv, research publications, and calculations using EN ISO 6946 methodology. Material thermal conductivity values are from BS EN 12524. All values are estimates — actual thermal performance depends on building condition, moisture content, and renovation history. This article is for informational purposes only.