Operating your heating and cooling systems with optimal efficiency
When it comes to saving on money and energy, what your HVAC systems aren’t doing is just as important as what they are. Just because your equipment is capable of running at peak performance at all times doesn’t mean it should be.
- During the heating season, winter in most parts of the world, set your building’s heat at a maximum of 21°C (70°F) when occupied. Lower the temperature to 16°C (61°F) when it isn’t occupied.
- Begin the day’s temperature pick-up with the outside air dampers shut so the building is at least 18°C (65°F) when occupants begin to arrive.
- Complete the building’s warm-up during the first full hour of occupancy.
- During the last hour of occupancy, begin the process of dropping the temperature.
- During the cooling season, or summer, set your air conditioner to no lower than 24°C (75°F) when it is occupied. Do not run the air conditioning when the building is unoccupied unless you are pre-cooling for morning arrival.
- Time that pre-cooling so the building is 26°C (78°F) when occupants begin to arrive.
- Keep the outdoor air damper open during the cooling season.
- At night in the summer flush the building with cool outdoor air.
- Make sure your heating and cooling set points are at least 2-3°C (3-5°F) apart. This will prevent the air conditioning from turning on and off.
- If possible, install variable speed drives on fans.
- Similarly, consider trading in fixed air volume systems for variable air volume systems.
- Also consider heating water pumps and chilled water pumps.
- Dual duct systems may be more efficient for your space than single duct systems.
Use your thermostat’s controls to maintain comfort and save on energy
Digital thermostats and other controllers are designed to make managing your business’s energy easy and efficiency, so take advantage of them.
- For optimal performance, your thermostats and controllers need to be in top shape. Calibrate all thermostats and gauges, test your controllers, and ensure dampers have tight closure.
- Digital thermostats are a must for automatically adjusting your building’s temperature at night, on weekends, and during other periods when it is unoccupied. This is where you will save significant energy and money.
- Keep your thermostat locked. If that isn’t possible, instruct employees not to adjust your settings.
- For larger buildings or more complex layouts, considering installing a building automation system. A BAS can control your complete HVAC systems as well as things like lighting (including emergency lighting), security, and fire safety. A BAS can save between 5% and 30% on your energy costs. It typically takes two to four years for a BAS to recoup its initial investment cost.
- In terms of water-heating efficiency, ensure that your water-heating equipment can heat to at least 45°C (113°F) without exceeding 60°C (140°F).
- Shut down circulating pumps during overnight, on weekends, and during other unoccupied periods.
- Consider a water heating temperature control that varies the temperature of your water supply in response to the outside temperature.
Save energy by powering down equipment when possible
The time-of-use electricity price structure may seem like it was designed to aggravate users, but if you can work around peak demand periods, there are major savings to be had.
- If practical, shut down any non-critical heating or cooling equipment during peak demand (and peak cost) periods
- Put off non-essential use of electrical water heaters, pumps and fans until off-peak periods
- Power down chilled water pumps, chillers, condensed water pumps, and cooling tower fans as early as is possible in the evenings as well as on weekends. If necessary, invest in a small stand-alone cooling system for server or computer rooms.
- If the outdoor temperature is above 18°C and no reheat is required, shut down your building’s heating pumps.
Only heat and cool spaces that need to be heated and cooled
Not all areas in your building have equal use or occupancy, so they shouldn’t be heated and cooled like they do.
- Areas like stairwells, lobbies and vestibules are only ever occupied for short periods. Either reduce heating and cooling in these spaces, or shut it off entirely.
- When the building is not occupied, use a timer to shut off exhaust fans in washrooms and kitchens.
- Turn off the supply air fan and outdoor air dampers one hour before occupants begin to leave.
- To cut down on cooling energy, turn of all unused office equipment, kitchen appliances and lights.
Avoid losing money to heat loss
You may not be able to literally watch your money escape through uninsulated pipes and high ceilings, but if you’re losing heat, you may as well be watching those dollars float away.
- Bare pipes and ducts that run through spaces that aren’t heated or cooled should be insulated in order to both prevent heat loss or gain, and to help deliver heating or cooling where it belongs.
- If you have a dual-purpose high-ceilinged building that has both offices and a warehouse, the office area absolutely requires its own ceiling as opposed to simply having wall partitions. Without a lowered ceiling, warm air will rise to the high ceiling and your heater will run continuously.
- On the same note, if your building’s ceiling is more than three meters (10 feet) high, you may want to consider the installation of ceiling fans that will push warm air back down.
- If your building features a loading area, you may want to consider installing a relay switch for your heating system so that when the doors open, the heat shuts off.
Perform regular maintenance to keep HVAC components clean
To get the most effective and efficient performance from your HVAC equipment, it’s essential it be kept clean.
- Mechanical cleaning techniques are employed to clean HVAC components like internal surfaces of air handling units, duct work, dampers, diffusers and fan components.
- Mechanical cleaning requires controls like physical barriers and devices equipped with HEPA filtered exhaust.
- Chemical sanitizers or biocides are typically used to clean components like heating and cooling coils and cooling towers.
- Cooling towers need to be cleaned to be kept clear of microorganisms, and also to minimize air and water pressure drops. This requires cleaning the intake strainer and inspecting spray nozzles.
- Condenser coil face must be kept clear of debris to maintain unrestricted airflow.
- Using a high-pressure mixture of water and detergent, clean refrigerant and water coils to enable maximum heat transfer.
- The reflectors in electric radiant heaters need to be checked for proper beam direction as well as cleanliness.
- Boiler tubes and water chillers need to be regularly cleaned.
Regularly inspect, maintain and repair all HVAC components
It probably goes without saying that keeping your HVAC equipment in top condition will ensure top performance. These are some of the steps you should be taking.
- Inspect ductwork, even flexible connections, for air leaks.
- Repair any leaks with caulking or tape, or by replacing flexible connections.
- Inspect dampers, edge seals, blades and linkages.
- Inspect inlet vane damper linkage to ensure control of airflow.
- Inspect air valves in dual duct mixing boxes to make sure they have proper seating.
- Insulate bare ducts or pipes.
- Inspect and adjust variable air volume boxes to ensure they are working precisely.
- Replace air filters regularly.
- Repair any leakage from taps, pumps, pipes and control valves.
- Install adjustable speed drives on chilled water pumps, heating pumps and fans, where possible.