How to choose a window profile for old Lithuanian project apartments

Introduction

Replacing windows in an old Lithuanian project apartment requires attention to specific constraints: narrow reveals, thin walls, standardized openings and limited mounting depth. This guide will help you choose a PVC profile, glazing unit and mounting strategy to get warmth, noise reduction, and long service life without overspending.

Quick summary

• Measure the opening depth and wall thickness before selecting a profile.
• Aim for a profile with 70 mm or more mounting depth and 3–5 chambers.
• Reinforcement (steel profiles) is important for larger sashes.
• Choose glazing balancing thermal performance and weight.
• Provide ventilation and micro-ventilation to avoid condensation.
• Proper installation and reveals fix most heat-loss issues.

Why old Lithuanian project apartments are special

Typical Lithuanian project buildings (Soviet-era panel houses) often feature:

• relatively thin external walls and limited mounting depth;
• standardized openings with little excess space around the frame;
• balcony blocks and uniform window sizes.

These features affect the choice of profile and installation method.

Key profile parameters

Mounting depth

• Look for a profile with at least 70 mm mounting depth. Narrow 60 mm systems are cheaper but may lack sufficient anchoring in thin walls.

Number of chambers

• 3-chamber systems are a minimum for panel-apartment replacements.
• 4–5 chambers provide better thermal and acoustic insulation, at the cost of increased frame width and weight.

Reinforcement

• Metal reinforcement inside the profile is essential for larger sashes or when the frame must carry heavier glazing.

Seals and hardware

• Dual-seal systems are preferred in Baltic climates.
• Hardware with micro-ventilation and opening limiters is useful for balconies and small rooms.

Choosing glazing

• A double-glazed unit with low-e coating and inert gas is the most cost-effective option for most façades.
• Triple glazing improves insulation and soundproofing but increases weight and may require stronger profiles and reinforcement.

Installation and insulation

• In old buildings, installation matters as much as the profile: warm installation using vapor-control and waterproofing tapes reduces thermal bridges significantly.
• Finish reveals carefully to prevent gaps between the frame and the wall.

Practical tips

• Measure openings in three places for height and width; many old openings are out-of-square.
• Consider external or internal extension elements if mounting depth is insufficient.
• Don’t skimp on sealing tapes and proper installation—an excellent profile can underperform if installed poorly.

Common mistakes

• Buying the cheapest, narrow profile without regard to the wall thickness.
• Overlooking the weight of the glazing and the need for reinforcement.
• Installing without vapor and waterproofing, causing condensation and heat loss.

Conclusion

Choosing a window profile for an old Lithuanian project apartment is a balance between opening geometry, insulation needs, and budget. Prioritize accurate measurement, a 3–5 chamber profile with a mounting depth of at least 70 mm, proper reinforcement where needed, and professional warm installation.

FAQ

Should I replace the windowsill with the window?

Yes. Replacing the windowsill during window replacement helps ensure proper moisture management and eliminate thermal bridges. Old sills can be a source of cold spots.

Is a 3-chamber profile enough or should I go for 5?

For most panel apartments, 3–4 chamber systems are sufficient. Choose 5 chambers if the opening faces a cold or noisy side and the wall depth allows it.

How important is hardware?

Very important. Hardware determines airtightness, ease of use and micro-ventilation features. Cheap hardware often fails within a few years.

What if there is limited mounting depth?

Consider expansion profiles or mounting inserts. In some cases a slight alteration of the reveal or the use of extensions is more cost-effective than changing the wall structure.

Will a new profile eliminate window condensation?

Partly. Modern profiles and glazing reduce cold surfaces, but condensation is largely caused by indoor humidity and poor ventilation. Address both insulation and ventilation.

Is warm installation expensive?

Costs vary with complexity, but warm installation typically adds 10–20% to standard installation prices. It's a worthwhile investment for energy efficiency.

Our specialists can perform an on-site measurement and recommend the optimal profile and glazing for your specific opening.