Building Costs
1. What did the green features add to the cost of the building?
- Bamboo floors - no additional cost
- Solar shading devices - about $8,000
- Low Volatile Organic Compund (VOC) paints and carpets - no additional cost
- Low emissivity windows - standard construction item
- Green roof -about $20,000
- Ecospace elevator - equivalent to electric traction elevator and lower operation and maintenance costs
2. How long before FCNL expects to recoup those costs?
About five years.
3. What was the cost per square foot to construct compared to the cost of standard office building?
This historic building had a significantly higher construction cost than a new building would have, but most of this is related to the requirements of working in an historic district adjacent to the U.S. Capitol complex.
Geothermal Heating and Cooling
4. Where are the geothermal wells located?
The ten 300-foot-deep wells are located under the parking area and garden near the alley.
5. What are the pipes in each well made from? How long are they expected to last? Can they be replaced easily?
The wells have a polybutylene tubing loop that is a closed circuit containing an antifreeze solution, similar to in an automobile. They are expected to last indefinitely. They can be replaced by excavating the ground.
6. Does the movement of groundwater underground affect the design and performance of the geothermal system?
Groundwater movement accelerates the heat transfer but is not essential to the performance of the system. The primary transfer is to the earth surrounding the wells.
7. What is going on in the big boxes in the basement mechanical room?
The equipment in the basement mechanical room is part of the split system heat pump: it works with the other portion of the heat pump system that is located in the office areas. The two parts of each heat pump are connected using a refrigerant that is ozone safe.
8. What is going on in the heating, ventilation, and cooling mechanical rooms on each floor?
The mechanical rooms on each floor contain the air distribution portion of the heat pump units. They are organized in zones, each of which has a thermostat for space comfort.
9. Will it be expensive to service and maintain this geothermal system?
Service and maintenance should be less than a conventional air system because there is less need to clean coils and the ground source heat pump compressors operate at lower head pressure reducing the stress on the machines.
10. What is the projected energy savings? What is the cost of geothermal versus standard heating, ventilation, and cooling?
We calculate that energy savings will be about 40 percent per year. The major features that contribute to the savings are the passive solar and daylighting, the geothermal heat pump system and the heat recovery on ventilation air.The additional construction cost for the geothermal heat pump system is about $4.50 per square foot.
11. Can homeowners install geothermal systems?
Yes, our architect, Burt, Hill, Inc., has designed an environmental cohousing community near Leesburg, VA, called EcoVillage, which uses similar geothermal heat pumps to heat and cool.
12. Are there pipes circulating heated fluid in the floors in winter?
Yes, tubes embedded in the lower level conference room concrete slab floor that provide radiant heat to this space. Upper floors have a forced-air heating and cooling system tied to the geothermal system.
13. Is any of the excess heat from the geothermal wells used to heat water for the building?
Yes, using a special geothermal heat pump unit that heats water coming from the city water supply. There is not a cogeneration system in this project.
14. Why is one hot water heater marked "potable" and the other isn't?
The hot water heater that is marked "potable" provides drinking-quality water to the plumbing fixtures. The other water heater heats the radiant floor system in the lower level conference room.
Wall Boards
15. Is the drywall really made from recycled flu ash from coal-burning power plants?
We specified the use of "recycled" or "synthetic" gypsum, which eliminates the environmental damage caused by gypsum mining and reduces waste. We have asked our general contractor, Kfoury, to verify that this is what the subcontractor used, but we are not yet sure of the answer.
Bamboo Floors
16. Where did the bamboo in the floors come from? Is it more expensive than hardwood?
The bamboo is harvested in eastern Asia, where it grows rapidly. It is comparable in price to hardwood and is harder than oak.
Green Roof
17. Is the vegetated roof better at reducing the heat-island effect and the summer cooling load on the building than installing a highly reflective roof?
The vegetated roof is similar to a reflective roof in reducing the heat-island effect but has additional benefits in reducing the storm-water runoff and reducing the cooling requirement of the building.
Comparison with the Old Building.
18. What portion of the old building was recycled?
The masonry building walls were the primary element that was reused. Also some portions of the roof framing system were reused. The materials that were taken out of the building were part of a construction and demolition waste management program to maximize recycling and minimize the waste that went to a landfill.
19. What is the total square footage of this building compared to the old building?
The new building is about 9,775 square feet, while the former building was about 7,056 square feet, an increase of about 38 percent.
Safety
20. What is the fire rating of the glass floors?
The glass floors are noncombustible but were not required to be fire rated due to the sprinkler system.
More about the building
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