Don’t shrug off the shoulder months! These early fall and late spring months bring specific energy management challenges and opportunities that shouldn’t be ignored.
Shoulder months are those in which temperatures outside sit comfortably between 45 and 65 degrees Fahrenheit. This means that the air outside is close enough to buildings’ ideal internal temperatures that engineers can open economizers and use all or mostly outside air. As a result, tenants get to breath fresh, comfortable air and well-run buildings can cut energy costs significantly.
Why is the temperature range between 45 and 65 degrees Fahrenheit ideal and not a temperature at which people feel comfortable?
“The ideal ambient temperature is a little lower than the ideal temperature inside because you have internal heat gains from things like computers, cooking equipment, people, and lights,” says Aquicore Product Engineer Connor Gray. “That all creates heat, so it’s a lot easier to heat a building than it is to cool a building.”
Temperatures vary significantly during shoulder months, and because they are close to the ideal ambient temperature for outside, building engineers often have to switch between heating and cooling on a day-to-day or even hour-to-hour basis.
While the amount of heating or cooling is generally lower than in the winter and summer, respectively, the difficulty in identifying which one a building should be doing on each day and switching on a dime can be very challenging. In some older buildings, switching may even have to be done by hand.
Real-time data monitoring from an energy management system can help building engineers to identify whether their building is drawing too much energy for heating or cooling, making the internal temperature uncomfortable, or even heating and cooling at the same time, as is commonly the case. Close monitoring allows for quick reactions to system inefficiencies and changes in temperature. At the end of the day, though, some degree of luck and intuition on the part of the building engineer will probably always be involved.
Another issue is that tenants have a habit of opening windows during these months. It’s understandable that tenants want to enjoy the fresh, temperate air outside, but when the temperature changes or they forget to close them overnight, it can result in significant energy expenditure. Submetering can help building engineers to identify tenant spaces that are drawing more heating or cooling than is necessary so that a gentle reminder to save energy can be conveyed.
While the ambient temperature’s proximity to the ideal inside temperature makes fine-tuning heating and cooling difficult in some cases, it also yields opportunities in a well-run building.
“HVAC costs are lower because the ambient air temperature is closer to the inside air temperature,” Gray said. “There’s just not a lot of heat you have to add or you have to remove to get to the right temperature.”
It’s also a great time to engage your tenants on energy costs. Shoulder months require more fine tuning, and engaged tenants are more likely to engage in energy saving strategies and less likely to become frustrated when temperatures run a little hot or cold. Investing time in engaging your tenants during shoulder months may also mean that they will work with you to reduce energy consumption during the summer and winter, when HVAC costs are considerably higher.