What Windows Should You Choose for an nZEB House in Romania? Complete Guide 2026

What is the nZEB Standard in Romania and Why Are Windows Critical?

nZEB (Nearly Zero Energy Building) is the mandatory standard imposed by Directive 2010/31/EU on the energy performance of buildings (EPBD) and transposed into Romanian law through Law 372/2005 as amended and HG 765/2016.

What nZEB specifically requires:

• Primary energy consumption: ≤ 100 kWh/m²/year
• Minimum requirement from renewable sources: ≥ 10% of total consumption
• Applicability: all new constructions in Romania since 2021

Why windows are critical:

In a house with walls insulated to 20 cm (U = 0.20 W/m²K) and roof at 30 cm (U = 0.15 W/m²K), windows represent the main source of heat losses. Even with Uw of 0.72 W/(m²K), a window loses 3-4 times more heat per m² than the wall. In a house with 15% of the envelope glazed, windows can represent 40-50% of total losses.

Section 1 — Minimum Technical Values for nZEB Windows

Uw Coefficient — Mandatory Thresholds

According to NP 048/2000 updated and SR EN ISO 10077:

Practical recommendation for nZEB: Uw ≤ 0.85 W/(m²K) for Zone II (Bucharest) — with a 15% margin against the legal limit of 1.0 W/(m²K).

Complete Technical Parameters for nZEB Windows

Energy Consumption Calculation

Heat transfer formula:

Q = U × A × ΔT × t

Applied to a 120 m² house in Bucharest (Zone II):

• Total glazed area: 18 m² (15% of envelope)
• Average ΔT cold season: 20°C (22°C indoor − 2°C average)
• Cold season hours: 3,500 hours

*Energy price €0.12/kWh (2026)

Section 2 — Recommended Profile Types for nZEB

Premium PVC — The nZEB Standard Solution

Salamander bluEvolution 92 (recommended by Neofort BIZ):

• 6 chambers, 92 mm depth
• Uf = 0.95 W/(m²K) — best in class
• Ca-Zn stabilisers (lead-free, cadmium-free) — REACH compliant
• 3 EPDM gaskets
• Uw with 44 mm triple glazing + Warm Edge: 0.72 W/(m²K)
• Uw with 52 mm triple glazing + Warm Edge: 0.66 W/(m²K)
• Certification: IFT Rosenheim, EN 12608 Class A
• Warranty: 40 years profile

Salamander bluEvolution 82 (economic nZEB solution):

• 6 chambers, 82 mm depth
• Uf = 1.0 W/(m²K)
• Uw with 44 mm triple glazing: 0.80-0.88 W/(m²K) — marginal nZEB

Aluminium with Thermal Break — nZEB with Premium Design

Alumil S77 Supreme:

• 77 mm depth, 34 mm polyamide thermal break
• Uf = 1.3 W/(m²K)
• Uw with 44 mm triple glazing: 1.0-1.15 W/(m²K) — at Zone II nZEB limit

Important limitation: Standard aluminium cannot achieve Uw ≤ 0.85 W/(m²K) — the recommended margin for nZEB.

Wood-Aluminium (Hybrid) — Premium nZEB

• Uf = 0.70-0.90 W/(m²K) — excellent
• Uw with 44 mm triple glazing: 0.65-0.75 W/(m²K)
• Cost: +50-80% compared to premium PVC
• Limitation: limited availability in Romania, long lead times

Section 3 — Optimal Glazing Configuration for nZEB

Recommended Glazing Pack (Neofort BIZ standard)

Triple 44 mm Saint-Gobain SGG:

4 mm Float / 16 mm Argon 90% / 4 mm Float Low-E / 16 mm Argon 90% / 4 mm Float

• Ug = 0.5 W/(m²K)
• Solar factor g = 0.32 (Low-E on position 2 facing middle chamber)
• Light transmittance TL = 70%
• Acoustic attenuation Rw = 34-36 dB

Warm Edge spacer — mandatory for nZEB:

• Conductivity λ = 0.15-0.2 W/(mK) vs λ = 160 W/(mK) for aluminium
• Reduces marginal thermal bridge from Ψg = 0.1 to Ψg = 0.03 W/(mK)
• Eliminates condensation on inner glass edge

Low-E variants by orientation:

• N/E facade: Low-E with g = 0.55-0.62 — maximises useful solar gain
• S/W facade: Low-E with g = 0.28-0.35 — limits summer overheating
• E/W facade: Balanced Low-E g = 0.40-0.50

Section 4 — Correct nZEB Installation

The most performant profile with the best glazing loses 30-50% of efficiency if installation is incorrect. The RAL standard defines 3 mandatory zones:

Exterior Zone — Water and Wind Sealing

Pre-compressed butyl band (Illbruck TP600, blaugelb TrioSDL):

• Withstands ≥ 600 Pa water pressure — tested per EN 1027
• Withstands ≥ 50 m/s wind — tested per EN 12211
• Durability: 20-25 years vs 3-5 years for classic silicone
• Applied to the window profile BEFORE installation

Middle Zone — Thermal and Acoustic Insulation

Semi-open cell polyurethane foam:

• Fills the space between frame and masonry
• Additional thermal insulation + acoustic attenuation
• Injected AFTER fixing the frame with metal anchors

Interior Zone — Vapour Barrier

PE film or butyl tape:

• Prevents vapour migration from interior to the joint → condensation → mould
• Applied continuously on the inner perimeter of the frame

Blaugelb Triotherm+ Preframes — for Complete nZEB

Preframes are available as a separate option and recommended for projects needing to achieve effective Uw ≤ 0.80 W/(m²K) overall, eliminating the thermal bridge at the sill:

• Composite material λ = 0.035 W/(mK) — comparable to mineral wool
• Reduces perimeter ψ from 0.08 to 0.01 W/(mK)
• PassivHaus Institut (PHI) certification
• Installed BEFORE the window, in the thermal insulation plane

Window Positioning in the Insulated Wall

Common mistake: Window installed in the middle of the wall thickness leaves the frame thermally exposed on both faces.

Correct for nZEB: Window installed in the outer third of the wall thickness (or on a preframe, in the insulation plane) eliminates the perimeter thermal bridge.

Section 5 — Real 2026 Costs

Indicative nZEB Window Prices (including installation)

*VAT excluded, standard installation (without preframes)

Additional Optional Costs

Amortisation Calculation for a 120 m² House

Complete FAQ — nZEB Windows Romania

What Uw is required for nZEB?

Romanian standards: Uw ≤ 1.0 W/(m²K) for Climate Zone II (Bucharest, Ilfov). Neofort BIZ recommendation: Uw ≤ 0.85 W/(m²K) with safety margin.

Is triple glazing mandatory for nZEB?

There is no explicit legal obligation for triple glazing. Mandatory is achieving Uw ≤ 1.0 W/(m²K). In practice, Uw ≤ 1.0 is achievable with modern double (Ug=1.0) + good PVC profile, but only marginally. Triple glazing (Ug=0.5) provides safety margin and superior performance.

What profiles are best for nZEB in Romania?

Salamander bluEvolution 92 (Uf=0.95 W/m²K) is the leading PVC performance available in Romania. Together with 44 mm Saint-Gobain triple + Warm Edge achieves Uw=0.72 — 28% below the legal limit.

Does installation matter?

Enormously. A bluEvolution 92 profile installed without pre-compressed bands and with thermal bridge at the sill can reach an effective Uw of 1.2-1.4 W/(m²K) due to infiltration and interstitial condensation — double the technical specification. RAL installation with 3 sealing zones is essential.

Aluminium or PVC for nZEB?

PVC for maximum Uw and cost-efficiency. Aluminium for large glazed areas (>150 cm width), large sliding doors and premium architectural design. Mix for villas: PVC for windows, aluminium for sliding doors.

What certifications must nZEB windows have?

• Declaration of Performance (DoP) per Construction Products Regulation (CPR) 305/2011
• Mandatory CE marking
• EN 14351-1 test for windows and external doors
• Profile certification: IFT Rosenheim or TÜV for declared Uf

What are the most efficient windows on the Romanian market 2026?

Salamander bluEvolution 92 + 52 mm Saint-Gobain triple + Warm Edge spacer + Blaugelb preframes: Uw = 0.66 W/(m²K) — the best commercially available system in Romania for residential.

Conclusion

Choosing windows for an nZEB house in Romania is not complicated if you follow this priority order:

• First the glazing: triple with argon + Low-E + Warm Edge → Ug = 0.5 W/(m²K)
• Then the profile: Salamander bluEvolution 92 → Uf = 0.95 W/(m²K)
• Installation: pre-compressed bands + 3 sealing zones → eliminate 30-50% losses through infiltration
• Preframes (optional but recommended): Blaugelb Triotherm+ → eliminate thermal bridge at sill
• Verification: Calculated Uw = 0.72 W/(m²K) → 28% below legal limit

Result: nZEB house with consumption ≤ 100 kWh/m²/year, energy bills reduced 40-60% vs standard construction, thermal comfort guaranteed for 40+ years.

Related articles:

• PVC or Aluminium for nZEB Homes in 2026?
• Triple vs Double Glazing: Real Savings on Heating
• Complete nZEB System: Salamander + Blaugelb + Triple Glazing

Neofort BIZ — nZEB window specialist in Bucharest and Ilfov. Request free technical consultation for your nZEB project.