Principia Boiler Conversion

Square Feet: 293,270 | Savings: 33% on gas bills | Reduced Maintenance |

During the energy audit, the steam boilers were found to be over-sized – a common occurrence. ERG converted Principia from steam to modular condensing hot water, and sized new equipment accordingly. Maintenance costs were reduced by eliminating many ongoing maintenance tasks.


When the Principia’s backup for its main steam boiler reached lifecycle and needed replacing, management wanted to secure energy savings and develop a hedge against future fuel cost increases, so the school contracted with ERG to redesign their heating system.

ERG analyzed existing loads and equipment capacities during the initial energy audit. The steam boilers were found to be over-sized – a common occurrence. This indicated that the boilers normally operated at a relatively low combustion efficiency rating.  During mild winter weather, a majority of energy was consumed in maintaining the boilers at steam pressure.

As compared to steam, modular condensing hot water boilers represent a more energy efficient heating technology. Less energy (MBH) is required to generate the same output, and the modular condensing boilers run at higher efficiencies under part load conditions.

In addition to a 30% reduction in gas usage, maintenance costs were reduced: water testing, blowdown, chemical treatment, and trap maintenance were all eliminated.

Principia’s entire campus is on one gas meter. The main building accounts for 54% of the load. The 33% gas savings achieved in the main building represents an 18% drop in campus usage and an annual savings of $33,870 (at 2003 gas prices). This provided Principia with a less than 10 year payback on the cost of the entire conversion – including the life cycle cost of a replacement boiler they needed to buy anyway.

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