high efficient boilers

Boilers vs. Water Heaters

The terms Boiler and Water Heater are sometimes used interchangeably. In the UK boiler is the equivalent to Water Heater in North America. See: Water Heaters Basics.

On the other hand, in USA the term boiler is mostly used in a strict sense: as a large device producing hot water or steam to space heating (though some models also provide hot water for domestic uses). We will use the term boiler in this sense: high-capacity appliances for space heating (and eventually to domestic water heating).

Types of boilers

There are two main categories of boilers: hot water and steam boilers.

The steam boiler distribution system comprises pipes and steam radiators; hot water boilers involve baseboard radiators or radiant floor systems, or coil systems to heat the air. Most steam boilers are used in commercial and industrial applications (restaurants, hotels, schools and institutional facilities).

We can also distinguish between the regular boilers (traditional models) and condensing boilers. Condensing boilers are much more efficient.

Types of fuel

New energy-efficient boilers can be gas-fired, oil-fired, combination oil/gas-fired, electric-fired or pellet-fired... Natural gas boilers are the most common choice.

High efficiency gas condensing boiler and pellet wood boilers can provide energy cuts up to a third in heating bills, when compared do regular old boilers.

See: Gas, Electric, Oil... Boilers

Efficiency and ratings

The overall performance of a boiler is given by its Annual Fuel Utilization Efficiency (AFUE). Many states demand minimum AFUEs  (80%, in U.S.), which is significantly higher than those of most old boilers (typically in the 55-65% range) but still below the most efficient units (95% and more).

Note: AFUE isn’t all; electric boilers have efficiencies around 100%, but that doesn't mean much.

When buying a boiler prefer a qualified one. For that, consider Energy Star rating, or certifications by UL, ASME and similar organizations.

Replacing an old boiler: sizing the boiler

Oversizing a boiler system will cause higher energy bills. Contractors, installers and manufacturers can help you decide about the size of your boiler.

Before you buy an high efficiency boiler (or implement any another heating solution) make sure your home is properly insulated. A well insulated home will demand a smaller heating system, which will save you energy and money.

For detailed information on insulation, see: Home insulation basics.
See also: Water Heaters Sizing

Alternatives to boilers

Modern high rated furnaces are an alternative to boilers. But if you have a boiler system (and the pipe system and radiators related with the boiler), furnaces are rarely un alternative (it isn't economical to install a furnace, based on warm-air and ductwork...).

Obviously, the reverse is also true, if you have a ductwork system...

Other environmentally-friendly alternatives to boiler systems comprise solar-powered systems and geothermal heat-pumps.

Boiler Manufacturers and Brands

See: Boiler manufacturers and brands

Boiler Thermostats

See: Boiler thermostats and controls