Multi-family HVAC is more complex than ever post-COVID
6 MIN. READ
Expectations for air filtration in buildings have gone up tremendously due to the impact of COVID-19. Property managers need to understand how to protect tenants while at the same time maximizing energy efficiency and making sure related HVAC upgrades do not hurt net operating income.
This article will provide some depth on multi-family HVAC in today’s new world, cover current trends and issues and give property managers some guidance on procurement of HVAC equipment, supplies, and contractors.
Ventilation expectations
This summer, the CDC (Centers for Disease Control) updated their guidelines for building ventilation in the context of COVID-19 risk mitigation. Many of these steps are based on new standards issued by ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers), publishers of widely accepted industry standards.
Here is a summary of recommended steps for building owners/operators:
- Introduce more outside air.
- Many buildings were previously set to the minimum setting for outside air. Operators should open these dampers beyond the minimum setting where climate permits doing so.
- Open windows where it does not pose health risks.
- Use fans to supplement airflow.
- Position exhaust fans to push indoor air outside and create circulation of fresh air introduced into spaces are particularly helpful.
- Be sure to position fans to avoid blowing contaminated air between individuals.
- Ensure HVAC systems are operating properly for the population of the spaces serviced.
- Rebalance and adjust systems to provide sufficient airflow to occupied spaces.
- Override demand control systems that regulate fan function so that fans are constantly running to provide airflow.
- Review supply louvers and exhaust grille placements and louver settings to optimize clean to less clean air movement in occupied spaces.
- Improve air filtration in your central systems.
Filter efficiency is rated by ASHRAE MERV (Minimum Efficiency Value), ranging from 1 to 16, with 16 the most efficient rating. Filter efficiency should:
- Aim for a minimum MERV 13 filter, which is at least 85% efficient capturing particles between 1 micron and 2 microns (between .0001 millimeters and .0002 millimeters), providing a better chance of capturing the COVID-19 virus than less efficiently rated filters. MERV 13 is considered “hospitality grade filtration.”
- Make sure filters fit their housing tightly to avoid airflow loss or leakage.
- For separate areas with high populations (like community rooms), consider strategically placed individual HEPA (High Efficiency Particulate Air) fan/ filter units. These units have filters are the most efficient available and are relatively inexpensive to buy and operate.
These are the initial editions of AHRAE and CDC guidelines for the COVID-19 era. Property managers should expect expectations for multi-family HVAC to go up in the future and anticipate more requirements in their future plans.
Other trends
Increased ventilation requirements are driving other trends in post-COVID HVAC. Below is a short list.
Explosive growth
Driven by the needs for upgrades, the U.S. HVAC market is expected to grow from $25.6 billion in 2019 to $35.8 billion in 2030, have a compound aggregate growth rate of 9.7% between 2019 and 2025 and create 13.3% more jobs between 2018 and 2028. COVID-19 exacerbated past shortages of skilled labor and its associated costs.
Offsetting costs created by increased ventilation standards
Increased filtration can cause lower airflow pressure, making HVAC systems work harder and raising operating costs. What’s more, the heavier use of outside air requiring heating, cooling, or dehumidification requires more energy. As a result, heat recovery technology is on the rise, with applications like heat exchangers or heat recovery wheels, which can recoup some of the energy lost by exhausting heated air to the outside. They can even reduce the size of HVAC systems used in new construction or renovations.
Because of increased demand caused by lower pressures, electronically commutated motors will be used in more HVAC systems to run pumps and fans more efficiently. These motors are brushless and thus easier to maintain. They are also more energy efficient than conventional motors and reduce energy costs.
Increased use of active neutralization technologies
To go above and beyond passive filtration, sophisticated technologies will see increased usage in more densely populated spaces. Examples are UV light treatment of air and even bipolar ionization treatment that uses charged ions to kill airborne pathogens.
Increased dehumidification control
The use of dehumidification to dry and cool building air is becoming more common in northern states. Because dry air retains less heat than humid air, dehumidification reduces the load on chillers and HVAC units.
More durable equipment
Longer run times and the impact of higher filtration for things like air handlers, fans, and HVAC units puts a bigger load on them. Manufacturers are building in more durability into this equipment.
Smart Building Automation Systems
For larger buildings, integrated BAS technology with open protocols will become more common in order to deal with increasingly complex operating requirements.
Other considerations for maximizing multi-family HVAC performance
There are a couple of basic design questions for a property manager to consider when retrofitting an existing multifamily HVAC system or installing one in a new building:
Centralized vs decentralized HVAC?
Like everything else, the answer to this question is: "It depends."
Centralized systems may work for larger buildings and offer the advantage of concentrating most large HVAC equipment in one area for ready access and maintenance. The downside is that because most buildings operate at less than full capacity 99% of the year, these large workhorses are idle most of the time. In addition, centralization increases single points of failure.
On the other hand, decentralized systems can flex to handle varying parts of the building at higher, more economical utilization rates. If one part of the building requires less heating or cooling, the systems for that section throttle down to save energy. You only use what you need, which makes sense for multi-family HVAC to address varying occupancy rates.
What’s more, decentralized systems are inherently redundant with fewer single points of total failure.
The correct selection depends on the individual characteristics and needs of your building.
Sealing ducts vs. ductless HVAC?
In the post-COVID environment, integrity of ducting is more important than ever. On one hand, leakage of unclean air, possibly with pathogens, increases the risk of COVID-19 transmission. In addition, it is expensive, with poor duct sealing leading to an increase of up to 20% in energy costs and possibly more with fans running more today than ever. It pays to regularly check duct integrity and correct any deficiencies promptly
Another way to deal with the inefficiencies of ductwork is to eliminate them completely and use ductless HVAC units.
Besides eliminating inefficiencies, ductless units usually have compressor controls that modulate them based on needs, rather that shutting off completely. This saves compressor start-up energy costs when demand requires. Another advantage of ductless units is ease of installation and low noise.
The major drawback to ductless units is acquisition cost, which is two to three times that of a ducted system. Maintenance requirements (for example, monthly filter cleaning) and costs are also higher.
Get the right help, and buy the right equipment
HVAC is already a complex category. In the post-COVID world, it is even more complex and, indeed, riskier. It is more important than ever to get expert help. Not hiring the best HVAC contractor increases the risk that you will pay more in the long run.
One way to find the best contractor is to find members of respected associations, such as ACCA (Air Conditioning Contractors of America) or those certified by RSES (Refrigeration Service Engineers Society).
Once you have the right contractors, you need help to manage them to demanding performance standards.
And remember, new demands for ventilation are putting heavier loads on HVAC equipment. So, buying the right equipment and supplies for your needs is important. In today’s inflationary environment, getting the best price is now more difficult, especially without the right technology enablers.
Raiven can help
Property managers can look to Raiven for help with procurement of equipment and supplies for multi-family HVAC in this tough market. Raiven Marketplace automates, centralizes, and simplifies the procurement process to help property managers find best value pricing.
Importantly, Raiven’s alliance with Avendra, a leading procurement company, provides access to pre-negotiated discounts of 7-25% on supplies (like filters) and equipment (notably, including Carrier, a leading HVAC equipment and parts manufacturer). All suppliers are pre-vetted for reliability.
For a free demonstration, contact us today!
