Wednesday, April 21, 2010

LEED Certification, When Is It Worth It?

Question from LinkedIn:
LEED per square foot: When is it worth it?

Nathan's Rather Lengthy Response:
We've started to pursue LEED certification for a lot of our smaller commercial interior projects (and all of our big full gut renovations or new construction projects). Once the contractors / designers have worked on a few projects, we've found no soft cost premium (and since we always put the LEED requirement in the RFP, only people who already know or are willing to learn on their dime will respond competitively). For those few firms who say LEED will be a big up charge, we ask why specifically. We will get ridiculous reasons like "to do the ventilation rate calculations", "to track C&D waste diversion", or "to do line of sight geometries." The obvious response is to ask how they were planning on sizing ventilation loads, confirming they were meeting our 95% C&D waste diversion requirement, or verifying the percentage of occupants who could see a window. Since these things are important to us, we have them as requirements in our contracts and construction documents. Since they're important to us, we expect teams to provide verification that they're meeting our requirements. Since they're preparing the verification anyway, there is almost no extra work to go for LEED. Since we are able to collect all of the LEED documentation and compare past projects to future projects, we're able to ensure that our buildings are getting better and better over time (making sure the learning that comes from a project stays with us rather than leaving with the project team). We have seen a tremendous benefit from commissioning but some reluctance on smaller projects, so we now offer an in-house commissioning service for these projects (we've seen amazing benefits even when only commissioning light controls and bathroom fixtures). We don't consider this an added cost of LEED, again because the benefits are so obvious all projects should be doing this, LEED or not. So on a small (say $500,000 classroom fit-out) project, the extra $3,000 seems well worth it to us.

Hard cost premiums are always optional and we evaluate those on a case by case basis in light of benefit to the project versus additional cost (LEED points being only a secondary concern). Added cost for MDF w/o urea formaldehyde? Yes, but the few buildings we've used urea formaldehyde MDF we've gone in, conducted IAQ tests, and can see elevated levels of formaldehyde in the space. Let's go with no urea formaldehyde (our standard). PV on the roof? Payback is generally more than 20 years (as a non-profit we don't get tax credits - this all changes with a PPA). We have other projects we can spend the money on with much better payback / environmental benefit. We typically don't go with PV. FSC wood is case by case. Improved HVAC equipment is usually a yes and we try to minimize additional cost by pursuing utility incentives and using integrated design to right-size everything / realize the interactions between systems.

I completely agree when you're doing most of the work yourself and you’re really passionate you can hold yourself accountable. My brother and I built his house recently and we held ourselves accountable (he did most of the work, but I helped on occasion and with equipment selection). The couple of thousand dollars extra for LEED for Homes was more than he wanted to spend (house cost $350 K). Though the house is beautiful and efficient, as money and time ran short, there are all sorts of minor corners that he or his subs ended up cutting that collecting documentation (which is VERY minimal in LEED for Homes) would have helped address. Admittedly, he's not really passionate about the environment (we was more concerned about utility bills), but imagine what happens as soon as you have somebody else doing your construction with little direct oversight from the owner. Without documentation many environmental claims can't really be trusted and history has proven this over and over again. On a side note, in his market (SW Michigan) he asked the appraiser about the ground source heat pump (what I think is meant by geothermal above) and was told they give no additional value for that system, though a propane tank does add to the home’s value. We went with the GSHP anyway, but only because the cost came in competitive with propane furnace. We didn’t go with the highest efficiency heat pumps because there was no way the system would pay for itself within its life span (we picked a mid-level unit – much of the winter heating is provided by a wood burning stove). How tight was the envelope when we were done? We don’t know because we didn’t do a blower door test. I’m sure he’ll continue to tell people it is tight though because he built it and he meant it to be tight.

Regarding the statement about LEED focusing on design rather than verification, of course this is why there is a LEED for Existing Buildings Operations and Maintenance rating system. All of the same arguments about certification apply. Of course you don’t need LEED to have a high performing building, but to be a good building manager you need to have an energy management strategy and track your utility bills on a monthly basis. You need to have a preventative maintenance plan and keep it up to date. You need to have staff training plans. You need to regularly do energy audits. Etc. If you are doing all of this, then LEED is very easy and has little cost. In all projects I’ve been on (more than 100 LEED projects), the teams that found LEED to be a lot of work were the ones that weren’t actually designing / building / operating in a sustainable manner and creating the documentation seemed hard because it forced them to actually go back and create documents that should have been created from the beginning if they were serious about sustainability.

Just my thoughts, not necessarily shared by Harvard, the USGBC, or anybody else with whom I'm affiliated.

Sunday, April 18, 2010

Why do Building Envelope Commissioning?

A few weeks ago the Boston area received a lot of rain, breaking records for the amount of precipitation in a month. During this time, the third story windows on the east side of our building leaked lots of water. Thankfully, the brick in this area is exposed and un-insulated because the space is semi-conditioned, though the brick on the rest of the building has been sprayed with 4” of Icynene open cell foam insulation and covered with drywall. After the rains, thick layers of scaling appeared on the brick surrounding the third floor window as well as the second floor window. The building, originally built in 1889, had two envelope consultants during the recent renovation. The close up picture shows one of the water drops falling inside of the building. Looks like it could have used some envelope commissioning.

Meselson Lab Commissioning

On Friday, we visited the Meselson Lab in the Biological Labs Building at Harvard University as part of the commissioning process. The space's renovation is nearing completion and the Office for Sustainability team was there to functionally test some of the equipment. We verified that the fan coil units (FCUs) and baseboard heating responded according to changes in the thermostat. OFS staff would adjust the thermostats to call for heating or cooling, Talli from Siemens would verify that the the BAS indicated that the system would react accordingly (picture above on the right), and OFS staff would watch the control valves turn and verify the temperature of the coils with a temperature gun (picture below on the right). While the systems reacting appropriately was generally the case, we did find one control valve for the baseboard heating that was unable to open or close because the metal baseboard cover prevented it from turning. This resulted in the perimeter heating being always on regardless of what the thermostat called for or what the FCU was doing. A simple change in control valve location will fix this.

Another potential issue was a discrepancy between the mechanical drawings and the actual HVAC system in one small room. The drawings called for a transfer grille between the small room with an unducted biosafety cabinet and a larger adjacent lab. Since there were insufficient existing wall penetrations, the contractor had used the location of the transfer grille to run the supply air duct. As a result, the room was very positively pressurized with the only path for air to leave being under the door into the hallway. You can see Kevin and Jay from OFS looking over the drawings with Talli from Siemens in the picture below.

We also looked at whether or not the fan coil units reacted to the manual fan speed switches (picture below on the right). Most did, though one seemed to only have an on / off reaction instead of the off / hi / med / low that was called for. We'll come back with a balometer or the testing adjusting balancing (TAB) contractor to confirm. The TAB contractor was supposed to be there on Friday (the reason we selected that date) but he didn't show up, so we'll have to come back to witness test some of the balancing, especially when it is done for the fume hoods. We also confirmed the occupancy sensors (Kevin is covering the sensor with masking tape in the picture below in the center) that control the lighting and the lighting levels at the bench level (Andrea is confirming the light levels in the picture below on the left). This space is not equipped with photo-sensors or dimming ballasts, so we weren't adjusting the light settings, just comparing the actual light levels to the Owner's Project Requirements and Basis of Design.