Miljöbyggnad — solar heat load
Legal status
Voluntary label. Miljöbyggnad is the Swedish building certification run by the Sweden Green Building Council (SGBC).
In Miljöbyggnad 4.1 (the current Nybyggnad/new-construction manual), the separate daylight (dagsljus) indicator from earlier versions (e.g. MB 3.x's Indikator 11) has been removed as a standalone indicator — daylight compliance is otherwise handled through the building code (BFS 2024:8). Daylight has not disappeared entirely, though: it resurfaces as a fallback condition inside the solar heat load indicator (see below), which is why SGBC's own documentation still refers to "i förekommande fall Dagsljus" ("daylight, where applicable"). This page covers the solar heat load (solvärmelast) indicator. For the indicator itself — definition, unit, how it is calculated — see Solar heat load (solvärmelast).
Requirement
Solar heat load is Indicator 2, under the Energi och klimat (Energy and climate) category, in Miljöbyggnad 4.1 Nybyggnad.
| Item | Value |
|---|---|
| Indicator | Solar heat load (solvärmelast), SVL |
| Definition | The instantaneous solar heat gain through windows for the worst-case room during the summer half-year, divided by the room floor area |
| Unit | W/m² |
| Assessment level | The least-favourable room in the building |
| Certification levels | Brons / Silver / Guld |
| Level | Bostäder (residential) | Lokaler (non-residential) |
|---|---|---|
| Brons | ≤ 38 W/m² | ≤ 40 W/m² |
| Silver | ≤ 29 W/m² | ≤ 32 W/m² |
| Guld | ≤ 18 W/m² | ≤ 22 W/m² |
Silver has an added glazing condition: the windows of the vistelserum concerned must have light transmittance LT ≥ 0.60. If a window falls short of that, the affected rooms must instead be shown — by a daylight calculation following the MB 3.2 instructions — to reach at least the Brons daylight level. So a daylight calculation is not required systematically to certify a building against MB 4.1; it only becomes a compliance route when LT < 0.60 for Silver.
This fallback threshold is not the same figure as BFS 2024:8's DF ≥ 1.0 % / ≥ 50 % — it's the daylight-factor criterion inherited from MB 3.2's own retired dagsljus indicator (Indikator 11), which sets its own three levels:
| MB 3.2 dagsljus level | Daylight factor |
|---|---|
| Brons | DF ≥ 0.8 % |
| Silver | DF ≥ 1.0 % |
| Guld | DF ≥ 1.3 % |
Similar order of magnitude to the building code, but a different threshold from a different source — don't conflate the two when checking compliance.
Calculation conditions (climate file, reference date and hour, shading assumptions): ??
Calculation setup
Not a daylight calculation — no reference plane, grid or sky model. The input is window geometry, orientation, glazing g-value and any fixed external shading, evaluated against a design-day solar load for the summer half-year.
How LUX handles it
Status: 🔜 Planned, not yet supported in LUX Live v0.3.0.
LUX computes daylight, not thermal load, so the solvärmelast figure itself is out of scope for now. The one place LUX-relevant daylight enters MB 4.1 is the Silver LT < 0.60 fallback above, where a daylight calculation must reach at least Brons — the calculation conditions for that fallback (per MB 3.2) still need confirming against LUX's own DF setup before it could be mapped directly onto LUX output.
Sources
- Miljöbyggnad — SGBC — Sweden Green Building Council (manual available to members / for purchase)
- Miljöbyggnad manual, indicator Solvärmelast — SGBC (paid / member document)