PVC windows for the Lithuanian project (new): practical recommendations

Summary

• Key Lithuanian climate and regulatory requirements for new buildings.
• How to choose a profile and glazing for thermal and acoustic performance.
• Recommended opening types and ventilation strategies for residences.
• Importance of correct installation, seals and flashing.
• Measures to prevent condensation and thermal bridges.
• Practical pre-order and handover checklist.

Introduction

When designing a new building in Lithuania, selecting PVC windows affects energy performance, indoor comfort, and compliance with local standards. This guide offers practical recommendations for architects, engineers and clients to choose correct window systems and avoid common mistakes in procurement and installation.

Regulations and climate considerations

Lithuania's climate requires attention to winter thermal performance:

• Aim for window U-values (Uw) around 1.3–1.1 W/m²·K depending on building energy class.
• Airtightness and seal durability under temperature swings are essential.
• Acoustic insulation: Rw 32–40 dB for urban locations depending on noise sources.

Tip: Check local building regulations for passive or near-passive houses where requirements are stricter.

Profile and glazing selection

• Profile: select a reputed multi-chamber profile (5+ chambers) to improve insulation and rigidity.
• Glazing: double or triple glazing with argon fill; Low-E coatings reduce heat loss.
• Target glass Ug: 0.5–0.7 W/m²·K for triple glazing; ~1.0 W/m²·K for double glazing where weight/cost are limited.

Note: Higher insulating glass increases weight — ensure hardware and frame can support it.

Construction, hardware and opening types

• Casement windows provide reliable airtightness.
• Tilt-and-turn windows are practical for ventilation and cleaning.
• Fixed units are useful where ventilation is not required and maximum performance is needed.
• Hardware with micro-ventilation and robust locking increases comfort and security.

Ventilation and condensation control

• Ensure mechanical or controlled natural ventilation: airtight windows increase the need for planned air exchange.
• Proper sill slope, thermal insulation and high-quality seals reduce condensation risk.
• Consider humidity sources inside and ensure proper vapor barriers in wall assemblies.

Installation, sealing and flashings

• Use the “warm installation” method: exterior side vapor-permeable, interior side vapor-tight.
• Install with appropriate foams, compression tapes and manufacturer-recommended sealing strips.
• Flashings and sills must be carefully designed; exterior silicone joints and tapes plus interior vapor barriers are necessary.

Important: Incorrect installation often reduces declared thermal performance by 20–40%.

Practical checklist before ordering and handover

• Confirm required Uw/Ug and acoustic ratings.
• Choose a certified profile and verified test results.
• Decide on opening modes and safety requirements.
• Agree on precise dimensions, tolerances and installation conditions.
• Plan ventilation, accessories (insects screens, blinds, sills).
• Sign a contract detailing warranties and installation responsibilities.

Frequently asked questions

• Which glazing for high urban noise? Use triple glazing with mixed glass thickness and wide air gaps to improve sound attenuation.
• Are trickle vents necessary? Yes, in airtight buildings; mechanical ventilation with heat recovery is preferable.
• How to avoid cold window sills? Use warm installation, insulation under sills and correct interior finishes.

Conclusion

Choosing and installing PVC windows for a new Lithuanian project requires attention to thermal values, correct installation and ventilation planning. Following the recommendations and checklist will help ensure long-lasting performance and indoor comfort.