How to maintain your HVAC system for maximum efficiency
Heating and cooling generally make up the majority of a building’s energy use—especially as easy upgrades like LED lighting reduce other energy loads. That makes running your heating, ventilation and air conditioning (HVAC) system as efficiently as possible critical to reducing your building’s environmental impact, keeping occupants comfortable and healthy, and lowering operating costs.
Best practices for day-to-day operations
Because the HVAC system is such a major building component and replacing it can be expensive and disruptive, it’s wise to do everything you can to keep it running at its best for as long as possible.
Miguel Sousa, President and Co-founder of Quebec City-based environmental engineering firm Ambioner, says it’s important to start with a basic understanding of the system you have:
- What type of system is it?
- What energy source does it use?
- What is the right maintenance schedule?
“That doesn’t mean you have to be an expert with in-depth knowledge of every component,” he says. Sousa points out that modern HVAC systems are highly complex, and calling on an HVAC specialist is often the best way to get end-to-end expertise.
If you don’t already know the basics of your system, an HVAC specialist can help you figure it out. With access to industry literature and information, they can tell you the expected lifespan and ideal maintenance schedule for each part, so you can plan and budget accordingly for upkeep and replacement.
Best practices that can help you prevent problems before they occur include:
- Replace air filters regularly. Air filters get clogged over time as they trap particles of contaminants from the air, making the whole system work harder to push air through. In addition to the increased energy use, clogged filters also have a negative impact on indoor air quality, so it’s important to replace them according to the manufacturer’s recommended schedule.
Check your settings. Most HVAC systems allow for a wide range of custom settings. Certain configurations can make a big difference in the amount of energy your HVAC system uses, especially scheduling settings.
“Adjusting your setback temperatures for when there’s no one in the building is one of the most impactful things you can do with zero investment,” says Bruce Taylor, President and Founder of Enviro-Stewards Inc., an environmental consulting firm based in Elmira, Ontario.
And be sure to leave space between your heating and cooling set points to avoid having those systems running at the same time and cancelling each other out.
- Use heat recovery if available. Systems with heat recovery can use exhaust air from inside to pre-heat or pre-cool fresh air from outside. This can significantly reduce how much energy your HVAC system must use to reach the right temperature and humidity level.
- Monitor system performance continuously. While Taylor and Sousa agree that having your system checked by an HVAC professional at least once a year is a good start, there’s a lot of monitoring you can—and should—do in the interim. For example, higher-than-expected energy use can be a sign of a problem, so consider installing sensors and amp loggers that can help you keep an eye on energy consumption and other performance metrics.
Every system and every building is different, so it’s also worth asking your HVAC specialist to recommend other measures you can take in your building to lower your overall energy use.
Take HVAC optimization to the next level
To improve efficiency even more, it helps to think creatively about the root issues your HVAC system is solving and other ways to address them using less energy.
For example, one of an HVAC system’s biggest jobs is providing fresh air to building occupants, usually by pulling in outdoor air all day, every day. At the Enviro-Stewards office, Taylor’s team installed a green wall and configured the ventilation system to filter exhaust air through the plants. This cleans the air naturally and lowers reliance on outdoor air, which in turn reduces the need to heat or cool that air to indoor conditions.
“We’ve been able to cut down our outdoor air intake by 97%,” says Taylor. “And tests are showing that the air quality we’re getting is actually better than in comparable offices with the standard addition of 10% fresh outdoor air.”
In another facility, the need for increased fresh air flow was driven by industrial welding, so Taylor’s team installed amp loggers and linked them to the ventilation system. When these sensors detect the surge in power that indicates welding is underway, they automatically signal to the system to increase ventilation until a set period after power levels return to normal.
In other cases, the HVAC system might be keeping inventory within a specific temperature range. Taylor says it’s worth remembering that it’s the temperature of the item that should be measured—not that of the air in the room. Ambient air can often differ from product temperature without affecting the inventory, and those differences can lead to significant reductions in HVAC energy use.
How to tell if something is wrong with your HVAC
The most obvious sign of a problem is if your HVAC system stops working entirely, but there are usually warning signs. If you notice any of the following during your regular system monitoring, contact your HVAC specialist to investigate and take action before the whole system fails:
- Unusual noises. HVAC systems are often noisy by nature, but there could be a problem if you notice it getting louder or making different noises than you’re used to.
- Visible rust. If you can see rust or other visible deterioration, that part is probably due for replacement.
- Water where it shouldn’t be. This is a sign that something needs repair. Take care of the issue as soon as possible to avoid water damage to your building.
- Low refrigerant fluid levels. Your HVAC is meant to be a closed system, so if your refrigerant needs topping up, that’s a sign that there’s a leak somewhere. Leaking refrigerant not only costs you more money and hampers system performance, but also harms the environment. Many refrigerant fluids are known contributors to global warming, so it’s important to keep them contained.
- Spikes in energy consumption. Whether you’re monitoring your energy bills or tracking your HVAC electricity use directly with amp loggers, any unexplained rise in power use should be investigated.
- Comfort complaints. Most components of an HVAC system are hidden, so it’s not always easy to spot problems. That’s why building occupant feedback should be taken seriously, as it often provides the first warning of an issue. An increase in complaints about temperature, humidity or air quality is a sure sign something isn’t working as it should be.
Is it time to replace your HVAC system?
With the right maintenance, you can extend the life of your HVAC system to its absolute maximum. But no system lasts forever, no matter how well it’s been maintained. Sousa recommends keeping track of the expected lifespan of your equipment so you can start planning and budgeting for replacement before you’re left with no choice.
“Unanticipated equipment failure can be a huge inconvenience,” he says. “It’s also likely to cost you more to replace than if you’d planned for it.”
As you start to approach the end of the expected lifespan, it’s also worth considering efficiency. If your current system is highly inefficient, there might be a case for early replacement.
But it’s important to weigh the environmental benefits of greater efficiency against the carbon footprint associated with disposing of your old system and manufacturing and transporting your new one.
When you decide to move forward with replacement, Taylor cautions against prioritizing the lowest possible purchase price.
“The cheapest option is almost always going to be the least efficient option,” he says. “And then you’re locking in that inefficiency for years.”
He notes that the purchase price of equipment often accounts for only 15% of the total cost of ownership—how much it costs not just to purchase, but also to operate and maintain the equipment throughout its lifespan. That’s why he recommends looking beyond the price tag when shopping for a new HVAC system and conducting a full cost of ownership analysis of any model you’re considering.
HVAC tips for business owners who are tenants
What if your business leases its space, meaning you don’t own the HVAC system? Even if you can’t control how the system is maintained or when it’s replaced, there are still things you can do to get the most out of the HVAC system in your building.
First, if you have access to thermostats and settings within your space, make sure you’re using them to their full potential. Program setback temperatures according to your work schedule and make use of any other energy-saving features that might be available.
If you don’t have access to any settings or you’d like to make bigger changes, ask.
“Landlords are sometimes more open to suggestions than you might expect, so it never hurts to ask,” says Taylor. Many upgrades will increase the value of the building, and many investments can be offset by rebates and incentive programs. If you do your research and come to the table with a solid business case, you might get the changes you’re looking for.
If the landlord isn’t willing, and you’re in a position to do so, offer to finance part or all of the upgrades yourself.
If all else fails, Sousa suggests using your presence as leverage when it comes time to renew your lease. He recommends negotiating for a break on your rent to offset the higher energy costs you might be paying for an inefficient system or shopping around for other spaces with better performance.
“Money talks,” he says. “Especially if you’re a bigger tenant, threatening to take your business to another building can be an effective way to get your landlord to come around.”