Westin St. Francis Hotel

The Property

Opened in 1904 and overlooking San Francisco’s historic Union Square, The Westin St. Francis Hotel is a northern California landmark. The hotel’s garage – a three-level, below-grade structure with a 250-plus-vehicle capacity – serves hotel guests, business professionals and tourists alike.

The Savings Opportunity

The hotel's garage ventilation system is powered by a 25-horsepower (HP) and a 15-HP exhaust fan motors, each running 24/7 or 8,760 hours per year, per motor. Prior to retrofit, their combined baseline of energy consumption amounted to 235,441 kWh, with a correlating peak kW demand of 26.9 kW. The annual cost to ventilate the garage amounted to $33,668.

The NES Solution

NES installed a "variable flow" DCV system in October 2012. It utilizes an innovative, smart-control logic that detects and measures vehicle fumes in the garage and then modulates garage fan speeds to prevent carbon monoxide (CO) levels from exceeding predefined set points (measured in ppm) for an extended period of time. The result was to enable hotel management to continuously ventilate the garage in an exceedingly energy efficient manner while ensuring the health and safety of hotel guests, staff and visitors.

Project Highlight

Energy Costs Cut by $31,800 Per Year

kWh and Peak kW Demand Reduced 94.7%

The Results

Post-installation measurements showed our garage DCV system reduced the garage fan motors’ combined kWh consumption by 222,999 kWh – a 94.7% savings. Peak kW demand was reduced by 25.5 kW – also a 94.7% savings – lowering the Hotel’s cost to ventilate its garage by more than $31,800 a year, from $2,800-plus per month to just $148 per month or less than $5 a day.

The project paid for itself in 14.85 months, not including a $19,700-plus rebate from PG&E.

About Nagle Energy Solutions (NES)

Nagle Energy Solutions, LLC is a manufacturer, distributor and installer of an innovative demand-control ventilation (DCV) system for commercial garages that reduces energy consumption in the range of 95% – with quantifiable savings as high as 97% achieved – all while leaving your garage fan motors running.

Our sales and service capabilities extend nationally and internationally.