: Look for sealed combustion condensing boilers . These are safer because they draw air from outside (reducing carbon monoxide risk) and are significantly more energy-efficient.
: Most modern boilers run on natural gas , but oil-fueled or electric options are available depending on your area's infrastructure. how to buy a boiler
: These provide both heating and hot water directly from the unit without a storage tank, making them ideal for smaller homes. : Look for sealed combustion condensing boilers