Expansive study of FortisBC's Efficient Boiler Program finds 16% savings in natural gas consumption.

FortisBC’s Efficient Boiler Program (EBP) is a boiler rebate program for commercial and residential customers. It applies to approved condensing and mid-efficiency boiler retrofits as well as condensing boiler installations in new construction.


FortisBC estimated that their Efficient Boiler Program (EBP) would result in a 15% savings in consumption, but needed the analysis and data to support their claim. In 2010, they approached Prism to conduct the savings analysis associated with the program.

Over 130 sites participated in the study, which included Multi-Unit Residential Buildings (MURBS), office buildings, schools, as well as miscellaneous sites which were included in an 'Other Buildings' category. The purpose of the study was to:

  • Evaluate the total energy savings, as well as the energy saved per sector
  • Analyze results by boiler efficiency level
  • Investigate the deviations in savings observed for the different sites (Sites which invested in a wider scope of energy efficiency upgrades including controls upgrades, for example, experienced higher savings than sites with boiler retrofits only.)


Using historical natural gas consumption data provided by FortisBC, Prism calculated the savings by comparing the current energy usage to a weather-adjusted baseline model for each site. Using Prism’s proprietary PUMA software, we prepared Cumulative Sum (CUSUM) graphs that reviewed the rate, seasonality, and consistency of the energy savings. Third party survey results were used to determine if any other system upgrades, which could have improved energy savings, took place in addition to the boiler retrofit. Using this information, we completed a statistical analysis of the savings from all building types and consolidated the results by sector and boiler efficiency type.


Building Type Average Annual Savings
MURB 18%
Schools 20%
Offices 13%
Other Buildings 9%

The results of the study showed that FortisBC’s EBP saved a total of 450,000 GJ at participating sites between 2006 and 2011. While the program delivered an average of 16% savings in 2010, the range in results was significant. MURBs and schools showed higher than average savings, while offices and 'other buildings’ experienced lower than average savings.

Unsurprisingly, high efficiency boilers were found to achieve above average savings, while mid-efficiency boilers resulted in below average savings. Additional savings were seen in sites where the boiler retrofit was accompanied by other system changes, such as upgrades to the building automation or a redesigned HVAC system.