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How did we reduce our utility bill by more than 40%?

In July 2016, Essex moved to Norcross, Georgia. Records from previous occupants show a monthly energy bill of approximately $1,500 for the 12,000-square-foot office/warehouse. With that in mind we implemented energy conservation measures.

1: Insulation

The first was spray-foam insulation on the underside of the roof deck. The lower level of roof already had a high-reflectance, TPO membrane. The front windows catch the full-east sun in the mornings and were coated with film to reduce solar gain. There are no west windows, the south end is shaded by trees, and the remaining windows are on the north side.

2: Lighting

In common areas, T-12 fluorescents were replaced with LED panel luminaires. In offices, three-lamp T-12 fluorescents were retrofitted with two direct-replacement LEDs.

3: High Efficiency Heating & Cooling

The original HVAC system had seven split systems with gas heat (1.5-ton to 5-ton). As part of pre-move-in renovations, four existing systems were replaced with three, high-efficiency (13 to 14 SEER) gas-fired systems. The fourth unit was fitted with a new gas furnace. Two of the original systems were taken out of service.

4: Nest Programmed Set Point Schedule

The operating systems are controlled with NEST thermostats which operate on schedules with night set-back temperatures of 80°F for cooling. Two units were programmed for shortened schedules on Saturdays and Sundays. The other two operate at the setback temperature from Friday evening through Monday morning.

We also added an outdoor air fan unit to supply pre-conditioned outdoor air to the general building. The outdoor air fan is an energy recovery wheel that manages an energy exchange between building exhaust and fresh outdoor air. We exhaust the air from the energy recovery unit into our warehouse to assist with tempering that space.

Since July, we’ve reduced our utility bill by 46-62 percent monthly. The latest NEST Report shows the building to be in the top 15% of “Nesters in your area.” September hours of HVAC operation dropped 146 hours from August, largely based on cooler temperatures, but also on raising some set points.

Going forward, we realize that the savings over time may be subject to increased occupant density and eventually bringing on one or two of the currently inactive HVAC units.


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