Issue: 10/02 Zurn/Qest manufactures the quiet Qest Hydronics radiant heating systems. These systems use cross-linked polyethylene (PEX) tubing and are commonly installed under floors in new construction. They may also be installed in walls or ceilings. The systems may also be installed as hydronic fin tube baseboard, using QestPEX cross-linked PEX tubing and Qest brass male and female copper sweat 1/2" and 3/4" baseboard fittings. The systems can also be used in snow and ice melting applications. QestPEX SIMS (snow and ice melt systems) can be installed underneath asphalt or concrete pavers or in concrete slab. Zurn/Qest.