Factors That Affect Building Energy Use


Getting to Know Your Building: Part 1

from EngineeredSystems March 2015 issue

We spend a lot of our time in buildings, and they use a lot of energy. Since they are using energy for you (and everyone else in the building), we don’t want them to use any more than required to meet your needs! In this article we’re highlighting the factors that affect how much energy a building uses. We’ve found about a dozen factors, and will expand upon a few that we think are important and are displayed on our energy dashboard. At the end, we’ll give you a few ways you can leverage these factors to save energy in your building.


The amount of energy a UC Davis building uses depends on:

  • How the building is used (laboratory, office, classroom, etc - see details below!)
  • The age of the building
  • The type of construction
  • Mechanical system type (and vintage)
  • Recent upgrades and maintenance on the mechanical equipment (especially the building’s control system)
  • Outside air temperatures
  • The occupancy of the building
  • The insulation of the building
  • Window type and shading
  • Heating, Ventilation and Air Conditioning (HVAC) Schedules
  • The sophistication of the temperature control system
  • Specialty equipment, e.g. lasers, MRI machines, etc.
  • The plug loads in the building


How the building is used impacts energy use.

Buildings can be used for a variety of functions: administrative offices, faculty offices, classrooms, laboratories for research and classes, food services, conference rooms, study areas and on and on. Many campus buildings are much more energy intense spaces than typical homes, as most homes don't include laboratories or industrial kitchens. We also have a lot more lab space on campus then you might think.  For example, although you might think of Young Hall as a classroom building, it's actually: 10% classroom space, 41% lab space and 37% office space.  

building types


We’ve grouped the campus buildings into five types that we call classrooms, laboratories, community, offices and housing buildings. Each type has an energy profile. For example, offices, classrooms, and community spaces generally use less energy compared to laboratories because some of the air is recirculated throughout the building. The recirculation of air allows for less conditioning (heating and cooling) of the air and results in less energy being used.

On the other hand, buildings with lab spaces typically use a lot of energy because they often require much higher ventilation rates than an office, and the air cannot be recirculated. The air coming into a lab must be 100% outside air (not recirculated), and then it must completely leave the building through the exhaust systems. Moving this quantity of air with fans, and heating and cooling the air, is an energy-intensive process.

As you can see, it's important to understand how a building is being used when looking at its energy use. You can look for your building on our energy dashboard– we encourage you to ponder the energy use in your space (and your coworkers spaces) and how it contributes to the whole building’s energy use.

ceed screenshot
The Campus Energy Education Dashboard sorts buildings by their type. Visit ceed.ucdavis.edu to find your building!




Why Age Matters


If you click on a building in the energy dashboard, you can see the year it was built. Some buildings on campus are even older than they seem! South Hall was first built in 1912 for $35,032. Think single-paned windows, and definitely not state-of-the-art insulation.  The age of a building and the materials used affect the building envelope (the physical separator between the interior and exterior of a building.)  The older a building, the worse the envelope, meaning heat will escape through single-paned windows, and cracks in doors, etc. This means it will take more energy to heat and cool the building since so much energy escapes through a poor building envelope. 



What can be done to save energy:

A few of the factors can increase the energy efficiency of a building, including upgrading the mechanical equipment, type of insulation, windows, and the sophistication of the temperature control system (thermostats and sensors). These types of changes can be very expensive though, so one low-cost measure we try to do is tune the building’s HVAC scheduling. You can help us tune the buildings’ HVAC schedules by using TherMOOstat to give us feedback on the temperature in your space.

Some factors are difficult to change because they affect the people in the building, such as the use of a building, its occupancy, and the need for specialty equipment. The last factor is the most important because this is where you can be the hero, plug loads. Plug loads include anything and everything plugged into the outlets in a building. Don’t forget about refrigerators, microwaves, and copy machines/printers. Some of our student interns have found that plug loads can be between 15-30% of a campus building’s energy use, so by doing what you can to save energy you can make a pretty big impact.


Here's what you can do to save energy in your building.

Some of the factors that affect energy use on our list above are building characteristics that can’t be changed, such as the type of constructionthe age of the building and outside air temperature. Factors such as the type of construction (e.g. concrete, brick, framed walls, etc), windows and insulation are affected by the California Energy Code, also called Title 24. The California Energy Code was created in 1978 and several newer versions have been released since then, each raising the bar for energy efficiency a little higher.

There are some easy things you can do to start making an impact:

1. Use TherMOOstat to give us feedback on the indoor temperatures.

The feedback you send using TherMOOstat feedback will help us create a comfort baseline and tune the building to suit occupants and save energy.

A TherMOOstat user submitting feedback

2. Investigate CEED and Trim Energy Waste

Complete our Trim the Waste program, where you'll look for your building on our energy dashboard and find areas of wasted energy in your building. We pass along what you find to the team of Energy Engineers, who see if they can cut this energy waste by tuning the HVAC schedules. 


Screenshot of CEED


3. Go Plug Load Crazy

Explore your building’s plug loads yourself and streamline your personal space using power strips and power-saving modes. Find out how much energy your computer and monitors are using with our Plug Load tool. You can also team up with your coworkers to save energy in the communal spaces such as kitchens and conference areas.

A graph of electric plug load



Where do we get our info?
The Energy Feedback Team is conveniently positioned in the Energy Conservation Office. This gives us great access to three key sources of info: the energy manager of ECO, a staff member with over 17 years of experience working with campus buildings, and a team of energy engineers currently working to tune buildings on campus. Together, we work diligently to improve energy efficiency and comfort all around campus. 

Energy Optimization in Existing Buildings

– Abaza, M. Engineered Systems. BNP Media, 27 February 2015. Web. 26 April 2016.