energy performance at near-passive scale

In SIP homes, thermal bridges are inherently fewer — no mortar joints, no reinforced-concrete-wall junctions. The remaining ones (slab-wall, window-frame) are controllable through careful design and weekly site supervision. That weekly review is therefore not optional; it is mandated.

heat pumps: a sensitivity to efficiency

An air-source heat pump's COP (Coefficient of Performance) tells you how many kWh of heat it produces per kWh of electricity. The market average is 3.5; with the heat load of a good SIP home and properly designed low-temperature underfloor heating, 4.0–4.5 is achievable. The impact is direct: 4.5 COP cuts the electricity bill by 28% versus 3.5 for the same indoor temperature.

solar: not always the win

An 8–10 kWp solar array can produce 90–110% of an average family home's annual electricity demand. Annually — but in winter (November to February) production drops to 20–30% of capacity, exactly when heating demand peaks. Gross annual balance is not the same as monthly bill balance. Battery storage (10–15 kWh) improves the situation but is expensive; Hungary's state-supported net-metering scheme (VHR) is currently the most common answer.

airtightness: the invisible exam

Hungary's n50 ≤ 1.0 1/h airtightness threshold underpins the stricter energy classes. It means that under 50 Pa pressure differential, the home's air volume exchanges at most 1.0 times per hour. Typical measured values on our SIP homes: 0.4–0.6 — twice better than the requirement; on traditional brick: typically 1.5–2.5.

We measure airtightness with a Blower Door test — on every SIP home, twice: at the end of construction (before finishes), and before handover. If the value worsens between the two readings, we localise the leak and fix it before handover.

summary

Energy performance isn't won by one choice but by coordinating five layers. The SIP structure gives an advantage — low U, few thermal bridges, good airtightness — but the openings, ventilation, heat pump, and solar each can boost or break the total. We commit to the target (class BB+ or passive-house) in writing at the first consultation, and we measure it before handover.