Burnham ES2 Boilers

Burnham ES2 boilers are cast iron, gas-fired hot water boilers built for chimney-vented installations, most often replacing an aging boiler in a home that already has a masonry or lined chimney. The ES2 runs on natural gas or LP gas and reaches 85 percent AFUE efficiency, putting it solidly in the standard-efficiency category rather than the condensing tier that needs PVC sidewall venting. An optional IQ Control System package can trim fuel use further, with most studies showing a 15 to 20 percent reduction in gas consumption. The cast iron heat exchanger is built for a long service life, backed by a lifetime limited warranty on that component. Contractors specify the ES2 when a straightforward chimney-vented replacement fits the existing flue better than a condensing boiler retrofit would.

Subcategories

• Standard ES2 Models: Standard ES2 boilers come in a range of input sizes to match various home heating loads, all sharing the same 85 percent AFUE rating and cast iron heat exchanger. Installers select a specific model size based on a heat loss calculation for the structure rather than simply matching the old boiler's output. Every size in the standard lineup vents through an existing chimney rather than requiring new sidewall venting.
• IQ Control System Models: ES2 boilers ordered with the IQ Control System add an energy-saving control package on top of the standard boiler, with most studies showing a 15 to 20 percent reduction in fuel consumption compared to a standard control. The IQ platform manages ignition and firing more precisely than a basic boiler control does. Homeowners replacing an older, less efficient boiler often choose this option to close some of the efficiency gap with a condensing model.
• Chimney Vent Kits and Accessories: Chimney vent kits and related accessories cover the connection between the ES2's flue outlet and an existing masonry or lined chimney, since proper draft is critical for a chimney-vented boiler to operate safely. Industry standard tapping locations on the ES2 are built to fit thousands of existing boiler installations, which simplifies matching new piping to old. Technicians should confirm chimney condition and sizing before installing any chimney-vented boiler, regardless of brand.

Buying Guide

Sizing a Burnham ES2 boiler starts with a heat loss calculation for the building, not the output of the boiler being replaced, since older boilers were frequently oversized by the standards used decades ago. An oversized ES2 short-cycles, wasting fuel and adding wear to the cast iron heat exchanger, while an undersized unit struggles to keep up on the coldest days of the season. Because the ES2 vents through an existing chimney rather than a sidewall PVC vent, confirming chimney condition and draft before ordering matters as much as sizing the boiler itself; a chimney that is too large, deteriorated, or shared with another appliance can prevent proper venting even on a correctly sized boiler.

Burnham ES2 boilers reach 85 percent AFUE as a standard model, which sits below condensing boiler efficiency but avoids the need for new PVC venting and condensate drainage that a condensing retrofit requires. That tradeoff makes the ES2 a practical choice in homes where the existing chimney is sound and running new vent piping would add significant labor.

Adding the IQ Control System package is worth considering on replacement jobs where the homeowner is focused on lowering fuel use, since the control package can meaningfully cut gas consumption without changing the boiler's basic venting requirements or footprint.

Frequently Asked Questions

What efficiency rating does the Burnham ES2 boiler have?

The ES2 is rated at 85 percent AFUE, which places it in the standard efficiency category rather than the condensing tier. It runs on natural gas or LP gas and vents through a chimney rather than PVC sidewall venting.

Can the ES2 replace a boiler that vents into an existing chimney?

Yes, the ES2 is designed specifically for chimney-vented installations and uses industry standard tapping locations that fit thousands of existing boiler setups. Confirming the chimney's condition and sizing before installation is still necessary regardless of how well the tapping locations match.

What does the IQ Control System add to the ES2?

The IQ Control System is an optional package that manages ignition and firing more precisely than the standard control, with most studies showing a 15 to 20 percent reduction in fuel consumption. It does not change the boiler's venting requirements or footprint.

How is an ES2 boiler sized for a specific home?

Sizing should come from a heat loss calculation for the building rather than matching the output of the boiler being replaced, since many older boilers were oversized by outdated standards. An oversized ES2 short-cycles and wastes fuel, while an undersized unit falls behind on the coldest days.

What warranty coverage comes with the ES2's heat exchanger?

The cast iron heat exchanger carries a lifetime limited warranty. Other components of the boiler follow the standard limited warranty terms listed in the installation and warranty documentation.