Quooker offers two different types of tanks. The PRO-VAQ series, available in two sizes, gives instant boiling water. The three litres PRO3-VAQ will suit the majority of households, but very large families or semi-professional cooks may want the seven litres PRO7-VAQ. The COMBI tank is a single tank which handles all your kitchen hot water needs as well as providing boiling water. If your kitchen tap is more than six metres away from your boiler, a COMBI tank under your kitchen sink could offer you significant savings in both water and energy usage.