Murkka Premium is a twin frame inward pivoting openable quadruple glazed wood-aluminium window with the external sash and frame having aluminium cladding. Fenestra Premium has very high sound insulation and heat retention.
Heat retention:
U-value = 0.57 (VTT estimated, measurements1230x1480)
G-value = 0.29 (VTT estimated, measurements 1230×1480)
Assumed sound insulation:
Rw = 44, Rw+C42, Rw+Ctr39 standard