Combination boilers provide hot water based on your demands, not water preheated and stored in a tank.
The water is heated as it flows through the combination boiler rather than a limited sized tank of water being heated as traditional water heaters operate. No matter how large your home is or how many people need hot water, you’ll never run out!

Most combination boilers have a life expectancy of more than 20 years. They also have easily replaceable parts that extend their life by many more years. In contrast, storage water heaters last 10–15 years. Combination boilers can avoid the standby heat losses associated with storage tank water heaters.

The good news is that combination boilers don’t require much maintenance, either. The system should be serviced as a part of the regular preventive maintenance that heating and cooling systems receive. Electric or gas components should be inspected.