No question, just need to vent: Why I hate LEED office buildings
JC72
| Posted in General Questions on
I’ve been in the office for over an hour and the temp has finally dropped from somewhere over 80 degrees to 75.
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Replies
John,
It's possible that your office has a poorly designed HVAC system. It's also possible that you are inflexible. It's summer, after all.
Most inhabitants of this planet are accustomed to 80 degree temperatures in the summer -- but these days, Americans aren't as tolerant of summer temperatures as they were a generation ago.
Ya, I get what you're saying. I do become accustomed 80+ degrees if it is 80+ degrees everywhere essentially all the time. Obviously that's not the case in a good portion of the US. Now the thermostat is pushing 72 and people are complaining about being cold.
As for a design issue you are in fact correct. We've been told that let the building temps are what they are because from an energy use perspective it was designed this way. I'm in a 20+ story LEED (Silver) 10 yr old office building with all sorts of wiz-bang tech to reduce energy use (motion sensor activated LED lighting, light activated motorized shades, etc). They'd save money if the set temp was 75 with run time that was an hour earlier in the morning.
I am not super familiar with LEED, but this is a common issue for many commercial buildings.
It is really a case of improper controls implementation and sometimes a commissioning/design detail issue. Commercial buildings really could use a protocol for comfort commissioning beyond design commissioning. Design loads don't always line up with use of spaces. Adjustments are often needed to address design issues. My office has linears that blow onto the termostats, ugh. The other issue is that these issues often need to be monitored for a day or two, and instead a tech gets sent to make an adjustment based on a complaint and is there for 20 minutes. A hundred random adjustments later, everything is out of wack.
There are probably some companies that are good at managing the comfort of these systems, but there are many that do not do good job.
The building I'm in now is decidedly not LEED, but has similar issues -- lots of fume hoods mean absurdly high levels of ventilation. Ventilation is also not balanced, which means:
A) The majority of air entering the building is not conditioned
B) Those fume hoods have to work a lot harder to meet minimum exhaust levels
C) The bathroom fans are purely decorative
D) The building is likely in violation of several local building codes
¯\\_(ツ)_/¯
We are allowed to wear short sleeve shirts though, which seems like a good solution to the issues you have.
I find three common problems in commercial buildings, which is where I do most of my work:
1- Way too much use of flex duct, and poorly installed flex duct at that (saggy, bendy, as far from straight as possible). This reduces airflow.
2- Broken or incorrectly set dampers. Some of the drop-ceiling vents have a damper control rod in the middle that you can operate by pushing or pulling. You might check that first since it's easy. The "rod" usually looks like a little plastic fastener sticking out a bit on a stick.
3- Missing or too-small return vents. Typically returns are sections of "egg crate" material used in place of a ceiling tile or two. The air return is usually the open space above the drop ceiling.
Controls are often secondary to airflow problems, but I've seen many poorly placed sensors too. Interior space temp sensors won't know the temperature in perimeter offices with windows, for example, so those perimeter offices will tend to run hotter than the setpoint in the summer.
It's entirely possible to build an energy efficient building that is also comfortable, but it takes proper planning and design. The last step with a commercial HVAC design is supposed to be balancing with an airflow meter on each vent, but this step is sometimes skipped. Most common is that the building WAS balanced at some point, but years of building maintenance people and office occupants tinkering with things messed up the original design.
Bill