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By Robert Shurell

With a well-thought-out plan, capital for improvements, and a bit of luck, the utility cost for operating an apartment building can be greatly reduced over the long-term operation of the building, and at the same time the value of the property can be increased. The opportunities are especially profound if the building has antiquated systems from the early 1900s. The 35-unit apartment building at 1515 Greenwich St., just west of Van Ness Avenue, has been the fortunate beneficiary of such an upgrade.

Purchased in 2005 by its current owner, the 1906 building was functionally stable, but not performing to modern standards of efficiency. The owner, trained as an architect, analyzed the opportunities and limitations of the building, and began developing a plan for a project that would make it a model of efficiency while adding long-term value.

There were several specific issues to address. The building provided no parking for tenants, and to provide this would be a valuable amenity in an area where street parking is scarce. The offer of an apartment unit with parking increases the value of each apartment over the remaining life of the building. Also, the structural design of the building provided one-way seismic resistance, meaning it was braced for an earthquake only in one direction; a perpendicular wave would render the bracing useless and put the building in danger of structural failure.

Further, the water delivery and distribution system to residential units was uninsulated and was based on a central boiler circulating hot water day and night, even at low-consumption times. This was a heavy drain on energy resources and very wasteful. Also, the electric lighting system required that common area lighting be on at all times. The windows were drafty single pane models. The walls were uninsulated. These were all wasteful and expensive misuses of energy resources, easily mitigated by modern technology.

In sustainable design, one is always urged to look at long-term goals at the beginning of a project, and develop “solution multipliers” based on achieving those goals. A solution multiplier is a scenario in which a single decision or action contributes to the realization of several identified goals. It is critical to the success of a sustainable project to recognize the solution multipliers at the outset, and keep those elements intact throughout the duration of the project, even though there will be issues and circumstances that may make it seem like a good idea to compromise them. The visionary project leader will understand that to compromise the solution multiplier may be to compromise the core integrity of the sustainability of the project. A solution multiplier can contribute in multiple ways to several goals, but if it is undermined, it can also create a domino effect and render the best of intentions unattainable.

In a commercial office building, an example of a solution multiplier is the use of depressed floor slabs with a raised access floor system above it. This allows many sustainability goals to be furthered. The space under the access floor many be used as a pressurized supply air plenum, which allows the air to be delivered at a lower, more ideal temperature, because the delivery is much closer to the occupant than an overhead delivery system that loses much of its heat as it is blown down from the ceiling. This reduces energy consumption, as the boiler does not have to create as much hot water, and pumps do not have to take it to the air handling units with enough volume to heat the supply air.

Access floors also contribute to sustainability goals by allowing tenant flexibility and controllability. Studies suggest that occupants who exercise some degree of control over their environment work more productively and are absent from work less often. With an access floor, the panels with adjustable air diffusers cut out are easily moved to the ideal location for the user. Overhead ducting is costly and intrusive to move. Further, the use of access flooring eliminates the need to hide overhead ducts with dropped ceilings. This, in turn, allows a greater amount of daylight to penetrate the space and more views for the occupant looking out. Similar to controllability, daylight and views have been shown to boost productivity and reduce employee absenteeism.

The solution multiplier at 1515 Greenwich was to excavate the existing crawl space below the building and turn the area into a full-height basement. This allowed parking, seismic strengthening, and hot water delivery to be assessed and upgraded. The upgrade has increased the overall value of the building and also improved the experience of the residents.

With parking in this area of the city so scarce, providing spaces for tenants to rent will bring steady revenue over the remaining life of the building. Although public transportation in this area is excellent and owning a car may not be necessary, providing some off-street parking will at least temporarily reduce congestion on the streets and lower the amount of fuel burned while prowling at low, inefficient speeds for a parking spot.

Even more important than the parking was the opportunity to upgrade the seismic resistance capability of the structure. The building was underpinned column by column as the excavation occurred, and a new foundation and basement column and beam system were constructed. This system consists of 16 moment frames of steel members that work in both directions to stabilize the building. (Moment frames are very stiff connections of beams and columns that resist twisting and bending in the connection and transfer it to the beams and columns, as these are less likely to fail. These are very effective seismic resisting assemblies, because the critical joints remain intact and allow the larger members to flex.) The sustainable result is obvious in this case: if the building falls down or is damaged beyond repair, it is not useful for future generations, and rebuilding will require an incredible amount of raw materials and embodied energy. It is a better strategy to upgrade and reuse what we already have.

The excavation under the building allowed an “on demand” water delivery system to replace the existing “continuously circulating” system. The genesis of the idea was to promote reduced fresh water usage by connecting the tenants to the costs of the water they use. To do this, individual submetering was required with dedicated hot, cold and return pipes to each apartment.

There was some concern because the design of the apartments had the bathroom and kitchen (the two water-using rooms in an apartment) separated, and served with water from separate vertical pipe chases. Therefore, the submetering had to occur in the newly excavated basement upstream of the branch-off to the separate chases. The submeters are connected to a wireless transmitter that records flow volume and generates an invoice based on that and the proportional cost of the gas to heat each tenant’s share of the hot water (hot water usage is monitored in the system as well). This system urges the tenant to control water usage through monetary penalties to those who waste.

Also, occupancy sensors were placed in inconspicuous areas of the kitchen and bathroom, and when a resident enters the room, a pump pushes a column of hot water to the tap within 30 seconds, so hot water is always quickly available even though it is not in constant circulation.

Motion sensors are also used to save on electricity costs. A lighting control panel utilizing a series of well-placed sensors controls the common areas of the building, such as hallways, stairs, plus the lobby and roof deck. The high efficiency fluorescent fixtures are programmed to be off (except for code-required egress lighting) at all times, unless an occupancy sensor is triggered. These sensors have been placed in strategic locations, such as around the corner from the area they control, so that by the time the occupant walks around the corner the sensor has been triggered and the lights are already on. The tenant never needs to know that the area was dark moments ago. Over the long run, this system is certain to save incredible amounts of electricity and decrease the demands on coal-burning electrical generation plants.

Since the owner took possession of the building, whenever a tenant moved out, the unit’s old single-pane windows have been replaced with modern double-glazed windows. These reduce air infiltration when closed, which allows the resident to set the thermostat at their desired end temperature, rather than set it higher or lower to take infiltration into account.

Also, modern low-emittance (low-E) windows reduce solar heat gain through the glass, reflecting it via a microscopically thin metal coating, without significantly reducing visible light penetration. This also allows the living unit to maintain a more constant temperature and therefore lower energy usage.

The owner also made it a point to place insulation in any wall whenever the wall was opened. The cost of insulation is small compared to the benefits it brings over the life of the building. Insulation in the wall cavity creates very small air pockets that trap the migration of air between inside and outside. Similar to the windows, this helps maintain a constant temperature in the living unit, reducing reliance on carbon producing utilities to heat or cool the space.

The building at 1515 Greenwich St. won the SFAA’s first Trophy Award for green design this past year. The vision of the owner to recognize the basis of sustainable design—the solution multiplier—and leverage it to its highest possible form is commendable and deserves this recognition. The owner was lucky that during the renovation the building experienced a turnover of 29 of its 35 units, making it easier to complete the work without inconveniencing the residents (luck does come into play often in construction projects).

This type of renovation is beneficial to both the owner and the resident because the owner recognizes higher rental rates over the life of the building and the satisfaction of providing a high-quality product with lower monthly overhead, and the resident enjoys the benefits of living in a building with cutting edge sustainable technology and imparting a smaller carbon footprint.

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The opinions expressed in this article are those of the authors and do not necessarily reflect the viewpoint of SFAA or SF Apartment Magazine. Robert Shurell is a licensed architect with Stantec Architecture and can be reached at robert.shurell@stantec.com. Copyright © 2008 by SF Apartment Magazine. All rights reserved.