AFUE Ratings are Not Accurate, Determine the Real Efficiency
Boiler rating or boiler efficiency is typically measured by Annual Fuel Utilization Efficiency (AFUE). AFUE ratings are not accurate.
Cast Iron Boiler
|AFUE Rating||82% – 87%||86% – 87%||Up to 87%|
|Real Efficiency||56% – 59%||56% – 62%||Up to 85%|
|Jacket Insulation||¾” to 1″ sides & top||¾” to 1″||Up to 4″|
|Base Insulation||No – boiler sits directly on floor||No|| YES insulated plus
boiler mounting stand
|Outside Air for Combustion||No||Optional||YES|
|Energy Saving Control||Not applicable
or not an option
|Additional Cost and requires trial and error adjustments||Energy Manager for combined heat and hot water standard on all systems. More efficient than indoor/outdoor reset controls|
|Integrated Hot Water System||Coil in boiler for hot water or electric||Coil in boiler (tankless coil) or indirect tank||High performance hot water storage tank with integrated control|
When the government created AFUE (Annual Fuel Utilization Efficiency) ratings, they had a good plan. However, AFUE ratings don’t help consumers make educated decisions about a hot water heating system’s efficiency because it only measures some chimney related losses. It’s like saying highway driving is the miles per gallon you’ll get all year when you know you’ll be doing most of your driving around town.
It’s time the heating industry had an accurate way to measure efficiency.
AFUE remains a misleading indicator that should be improved with an index that truly measures a hot water system’s efficiency. The heating industry needs it. The homeowner deserves it. Once you’re able to accurately compare different heating system’s efficiency,