An instantaneous gas fired water heater produces hot water on demand when it is required. They are ideal for small homeowners with a big demand for hot water. They eliminate the need for a hot water cylinder. All Chaffoteaux & Maury models are at home when it comes to meeting domestic needs, even in low water pressure areas, . And because they only heat the water as it is used, they’re extremely hot on efficiency and saving money too. Hide this answer