5 ms·Convenient but inefficient.by orra 6y agoConvenient but inefficient.sjg007 6y agoSo water heaters are inefficient? I’m confused, they save time.orra 6y agoI mean the thermal (and hence, electrical) inefficiency of keeping hot water warm all the time. Similarly, even with good insulation, a combi boiler is more efficient than having a hot water tank.