Insulation or heat-pump installer did bad work — what do I do?
BW 7:750 + 7:759 (works contract): right to repair or replacement. Building Code + ISDE minimum requirements as leverage. €19 letter.
On defective insulation/heat-pump installation your rights sit under BW title 7:12 (works contract): (1) right to repair by the same contractor (BW 7:759), at no cost; (2) on refusal: right to substitute performance by a third party + cost recovery from contractor; (3) on gross fault: contract termination + damages. Plan: (a) photos + measure performance loss (heat meter, thermography); (b) written demand within 2 weeks of discovery; (c) ISDE application: minimum requirements not met = ISDE entitlement at stake → leverage; (d) on refusal: VLOK building disputes committee or civil court. For heat pumps: STEK/Solis-certified installer = 2-5 year connection guarantee.