When you need hot water, you need it fast and it have to be there. Thats where a propane tankless water heater come in. Unlike old-fashioned ones that keep big tank of water hot all time, even you not using it, propane tankless heat water only when faucet turn on. This mean you get endless hot water, and dont waste energy keeping warm. Like magic fawcet that give hot water as long you want. Really good for busy homes where lots people shower or do laundry same time. Plus units usually smaller and mount on wall, that save space. Vangood make these kind smart water heaters, they built to last and give reliable hot water, also save money on energy bills. Modern way for everyday need, work by using propane gas to heat water as it flow thru the unit. Much more efficent than old tank heaters. For a great example, consider the 6L Outdoor Camping Gas Water Heater Portable Instant Propane Water Heater for Camping Hiking RV Travel Shower.