The Viessmann Vitodens 100-W Heat Only Boiler is a light and compact boiler with an Energy Related Product A rating. It boasts an Energy Related Product efficiency of 92%, making it economical to run and saving you money on energy costs. This boiler is also hydrogen-ready, incorporating renewable energy for efficient operation. It features the Viessmann Matrix Plus Burner, which reduces fuel consumption and regulates heat production, and an Inox Radial Heat Exchanger made of durable stainless steel. These components ensure efficient and reliable performance for your boiler and heating system.