NZEB Decision Guide

Find the right glazing for your nearly zero-energy building.

Answer five short questions about your building. We apply the EThCE framework — Energy, Thermal comfort, Cost-effectiveness, Environmental impact — to rank 10 glazing technologies for your specific situation.

40%

EU energy from buildings; glazing drives 20–60% of envelope heat loss.

glazing technologies assessed — from double to BIPV & vacuum.

EThCE criteria weighted: Energy, Comfort, Cost, Environment.

1 Profile Climate, type, WWR, orientation
2 Energy Performance by climate & strategy
3 Comfort Thermal comfort for occupants
4 Cost Upfront cost & payback range
5 Result Ranked shortlist with rationale

Step 1 of 5

Your building profile

Climate zone

Where is the building located?

Cold — Nordic / Baltic

HDD >3000 — long heating season, low solar angles. Finland, Sweden, Norway, Estonia.

Mixed — Central Europe

Balanced heating and cooling loads. Germany, Poland, Austria, Switzerland, UK.

Hot — Mediterranean

Dominant cooling load, high solar radiation. Spain, Italy, Greece, Portugal.

Building type

Primary use of the building.

Residential

Single-family, apartment, or multi-family housing.

Office / Commercial

Office, retail, or mixed-use commercial space.

Window-to-wall ratio (WWR)

Approximate glazed area as share of facade.

Low — under 20%

Modest windows, well-insulated opaque facade.

Medium — 20–40%

Standard proportion, typical of most new construction.

High — over 40%

Large glazed areas, curtain-wall or floor-to-ceiling glass.

Dominant facade orientation

Which direction does the main glazed facade face?

South-dominant

Main facade faces south — high solar gain potential.

North-dominant

Main facade faces north — low direct solar gain.

Mixed / Unknown

Multiple orientations or orientation not yet determined.

Source: Moghaddam et al. (2023), "Comprehensive Review and Analysis of Glazing Systems towards Nearly Zero-Energy Buildings", License: CC BY 4.0 Interactive tool ©Innopedia.

Step 2 of 5 — Energy Performance

How each glazing type performs for your profile

Energy scores reflect U-value and g-value performance under your climate zone and orientation. Higher is better. Source: Table 1, Moghaddam et al. (2023).

Energy Performance Scores (1–5 scale)

Glazing technology	Energy score	Key finding

Step 3 of 5 — Thermal Comfort

Occupant comfort implications

Comfort scores reflect risk of radiant asymmetry, cold-surface discomfort, and overheating — key factors for NZEB occupant wellbeing. High WWR amplifies these effects.

Thermal Comfort Scores (1–5 scale)

Glazing technology	Energy	Comfort	Comfort note

Step 4 of 5 — Cost & Payback

Cost-effectiveness across your options

Payback periods are indicative ranges based on published literature. Advanced solutions carry higher upfront costs but may be justified over lifecycle, especially with energy generation (BIPV).

Budget sensitivity

How important is upfront cost vs. long-term performance?

Cost-first

Prefer lower upfront investment; longer payback is a concern.

Balanced

Weigh performance and cost equally across the lifecycle.

Performance-first

Prioritise best outcomes; willing to invest for long-term gain.

Building size

Larger buildings benefit from economies of scale on advanced systems.

Small — under 200 m²

Single-family home or small commercial unit.

Medium — 200–1000 m²

Apartment building, small office.

Large — over 1000 m²

Commercial, multi-story or public building.

Indicative Payback Ranges

Glazing technology	Upfront cost	Payback range	Cost score

Step 5 of 5 — EThCE Recommendation

Your glazing shortlist

Scored across Energy (35%), Thermal comfort (30%), Cost-effectiveness (20%), and Environmental impact (15%) — weighted per the EThCE framework.

Top Recommendations

Full Ranking

Rank	Glazing technology	Energy	Comfort	Cost	Env	Final score

Scores are indicative and based on published research ranges. Engage a building energy consultant to validate glazing selection for your specific project. Source: Moghaddam et al. (2023): "Comprehensive Review and Analysis of Glazing Systems towards Nearly Zero-Energy Buildings."