If you said heating and air conditioning, or climate control, you answered correctly, and your answer is confirmed by multiple research studies. The use of modern air conditioning in office buildings and homes came into general use in the 1950s. It made it possible for people to live and work comfortably in sweltering environments such as Phoenix, Las Vegas and much of the American Southwest. And it made the summer humidity of the Midwest, South and Northeast tolerable. As great an invention as air conditioning was, most HVAC systems still are far from perfect. Outside environmental factors, and simple things such as the orientation of the building to the stronger summer sun, can overtax a poorly designed system.
In a typical office building, heating and cooling represent about 48 percent of total energy use (Commercial Energy Advisor, E Source). Even if you have a full-service lease, where the landlord pays the operating expenses in the building for the first year, typically in the second and subsequent years, as the energy costs go up, you as the tenant will pay the increase. This clearly makes the HVAC system a significant operational cost deserving management attention.
HVAC systems are tasked to reduce interior heat, and in some cases humidity, which is caused by weather or environmental conditions. Besides a building’s orientation, what else can affect HVAC performance and your resulting comfort?
Exterior glass. Unless the building has recently been constructed or has had its windows (glazing) replaced or upgraded recently, outside heat can easily transfer into your space. Inefficient window blinds, or the lack of them, can make it worse.
Use of space. The type of office equipment you have and are running, also affects your environment. For example, server equipment creates additional heat.
Human body heat. We all run at about 98.6 degrees. Put a lot of people in a confined area, such as a conference room, and you have a problem, especially if the HVAC system was not designed for a larger population.
Let’s talk about various types of HVAC systems. The most commonly encountered HVAC arrangement is a split-system. This is often used in residential construction or smaller commercial buildings below 10,000 square feet. A split-system is identified by the presence of an outside condenser unit, sometimes located in the landscaping or on the roof of the building. The furnace is inside the house or office building, hence the description “split-system.”
Split-systems are cheaper to install, offer smaller zone sizes, and have low noise transmission. A flat roof is not required for installation. However, they require multiple condenser units outside the building, either in the landscape or on the roof. It is more costly to add an energy-saving economizer unit later and they are typically limited to two-story building.
Packaged rooftop systems contain a condenser, compressor and heat exchanger in one unit and as implied, is located on the roof of the building. Installations require either a flat roof or a flat area on the roof. This system is capable of servicing larger buildings than a split system, but is best used on a two-story building. Incidentally, the life-expectancy is between 10-20 years depending on how they are maintained, which is a good reason to ask the landlord how old the building or units are. The advantages of a packaged system are that it is a simple, single piece of equipment located outside the occupied space, and is easier and cheaper to install an economizer unit at
a later date. However, while it can service larger zone sizes, it has limited minimum zone size, which means you may not be able to control very small zone (server rooms.)
The last commonly encountered HVAC is the central plant system. These are used in multiple-floor or downtown high-rise type buildings. They often include separate boilers, heat exchangers and chillers. Ask the landlord if it is a water-cooled or air-cooled chiller, since air-cooled chillers can have a more difficult time delivering the desired inside temperature when the outside air is at or exceeding 100 degrees.
Centralized systems have air handlers, which are tasked to move air throughout the building. They are often referred to as variable-air-volume systems or VAV. VAV allows tenants the most options regarding zones they want to cool or heat, which can be important during the spring and fall, when the days start chilly and become warmer. The central plant provides the most options and flexibility, plus the basic ability to cool or heat a larger, higher structure. It allows more options for individual zone controls than are generally associated with packaged units.
Which should you consider when trying to anticipate your comfort in a new location?
Orientation of the offices to the stronger, summer sun. Don’t be dazzled by the view in October and November and forget where the sun hits in July and August.
Age of building and capacity of its exterior glass. As a rule of thumb, the older the building, the less capable the windows will be – also it would follow that the older building will be more prone to have HVAC operational problems.
What is often overlooked or not apparent, when the space had been previously occupied, is whether the air conditioning ducts and outlets were relocated after interior partitions were constructed. When the system is not reconfigured for the new tenant, the HVAC is almost always doomed to failure.
What are the characteristics you should look for in an HVAC system?
Ideally, an HVAC system should possess a CO2 sensor that activates the system to produce more air changes with fresh air which prevents feeling sluggish and less productive.
It should also have enough control zones that address different sun exposures and use of the space during the day. In other words, the morning sun vs. afternoon sun, and the number of people or occupants you have in your space. For example, your conference room may be a walk-in freezer until you pack it in with enough people or it gets so stuffy or warm that your audience struggles to stay awake.
While harder to identify, ceiling duct work that was properly installed and “balanced” will ensure air is delivered where and when it is needed.
These are just a few of the factors that should be taken into account when evaluating a potential property. As a commercial real estate broker working solely on behalf of the tenant, it is my goal to ask and get the answers for these questions before you commit to a lease.