Achieve Unmatched Yields with the Ideal Cannabis HVAC Solution

If you want to create the perfect indoor growing environment for cannabis cultivation, it does require some careful planning and precise control. This requires the grow room to have a properly sized cannabis HVAC system. Only a properly sized cannabis HVAC system will provide the perfect temperature, humidity and airflow control for cannabis growth, and the grower will be able to harvest top quality and abundant cannabis.In this blog, let's learn how to choose the right size cannabis HVAC system for your grow room. We'll start with the importance of a right-sized cannabis HVAC system for your grow room and explain the elements that affect the size of your grow room HVAC.

Understanding Cannabis HVAC Sizing Basics

Why is a properly sized cannabis HVAC system important? Because the size of the system is not only related to energy consumption, but also has a direct impact on the health of the plant.

Why Correct Sizing Matters

Cultivation rooms involve many more variables than standard environments, and growers wanting to achieve adequate control over environmental conditions need to rely on correctly sized cannabis HVAC systems. The health of cannabis depends on good control of environmental conditions, but there are also implications for energy consumption and capital, operating and maintenance costs.

Impact on Energy Efficiency

If an cannabis HVAC system is oversized, it may be too capable and run on short cycles, constantly starting and stopping, which in turn leads to wasted energy. A properly sized air conditioner, on the other hand, will be able to operate at peak efficiency, thus maintaining a stable temperature and humidity level without overloading or running inefficiently. Properly sized cannabis HVAC system is efficient, uses less energy, and reduces electricity bills, so overall operating costs can be reduced.

Consequences of Over-Sized Units

Firstly, oversized air conditioners cost more to purchase and they require far more energy to run than is actually needed. Second, oversized systems can lead to rapid temperature changes along with potentially inaccurate humidity control. Excessive dehumidification or humidification can make the environment inside the grow room unsuitable for marijuana growth, increasing the risk of mould and disease. Finally, an oversized system means that it is running when it is not needed to, thus placing an unnecessary load on the equipment, which may further accelerate deterioration and damage.

Risks of Under-Sized Units

If the cannabis HVAC system is undersized, it may not be able to provide sufficient cooling or heating capacity, and so may result in high or low temperatures in the grow room. At the same time, an undersized cannabis HVAC system may not be able to remove excess moisture or provide sufficient humidification to the grow room, and so may result in wide fluctuations in humidity levels within the room. Unstable temperatures and humidity levels in the grow room can have an effect on cannabis.

Key Factors Influencing Cannabis HVAC Size

There are many factors that influence HVAC sizing choices, but in this article there are three main ones to talk about: the environmental control requirements of the grow room, the type of marijuana and its growth stage, and the specific conditions of the grow room.

Environmental Control Needs

The effects of temperature and humidity on marijuana have always been present throughout the growing process of cannabis cultivation. The importance of temperature and humidity to marijuana growth is undeniable, so the HVAC that growers choose needs to be able to accurately control the temperature and humidity levels in the growing room.

Specific Grow Room Requirements

Growers may classify the grow room as a mother room, cloning room, grow room or other, and the different uses of the grow room correspond to the different stages of cannabis cultivation, so the environmental control needs of the grow room will be different, and the cannabis HVAC requirements will be different as well. On top of that, different types of lighting, the amount of marijuana, and whether or not other equipment is used in the grow room will all have an impact on the cannabis HVAC system size and needs. For example, the use of high-intensity lighting in a grow room creates additional heat, which requires more cooling capacity to balance it out.

Common Misconceptions

Many growers often get into a misconception when choosing the size of their cannabis HVAC system. For example, some growers think that they only need to choose a large cannabis HVAC system to handle all their needs and solve any problems. This is not the case, and as we discussed earlier, an oversized HVAC can lead to wasted energy.

Some growers also get into another misconception that all grow rooms need the same HVAC configuration. In reality, every grow room requires a different sized HVAC and a different configuration because of its different purpose or function. Growers cannot afford to take a one-size-fits-all approach, and each grow room requires the most appropriate cannabis HVAC system for the specific situation.

Determining Room Use and Specifications

Growers need to plan and lay out their HVAC before choosing the right size. Growers also need to consider whether they plan to expand in the future when deciding on the use of each room, and if they need to take this into account in their initial planning.

Assessing Room Dimensions and Layout

The grower needs to measure the length, width and height of the grow room and then calculate the area and volume of the room based on a formula. The next step is to think about the layout of the room, such as the placement of plants, lights and other equipment: will the marijuana be grown in a single shelf or multiple shelves? Will the lights be HPS or LED, and will there be a dedicated area for operation and maintenance?

The grower also has to consider airflow and ventilation based on the actual layout of the room. Airflow distribution and duct design are the most important factors in ensuring the success of a facility, especially if the grower is using multiple tiers. Good design and layout will go some way to avoiding the problems of microclimates that can occur when air flow is impeded due to improper layout.

Identifying Room Function and Purpose

Rooms within a grow room may require different environmental conditions depending on their function. For example, a grower may divide a room into a cloning room, a growing room, a flowering room, etc., depending on the stage of growth of the cannabis, such as the seedling, asexual reproduction and flowering stages.

Typically the seedling area may require higher humidity and slightly warmer temperatures to promote growth, while the flowering area may require more light and finer humidity management to prevent mould problems.

This requires the grower to have separate cannabis HVAC systems for the different functions of the room, making it easier to adjust the growing conditions to the actual needs of the cannabis.

Planning for Future Expansion

The cannabis industry is in a phase of rapid growth and the possibility of business expansion is always there. Growers also need to have a long-term perspective when choosing a cannabis HVAC system.

So when a grower is choosing the size of their cannabis HVAC system, they need to figure in the possibility of expanding the growing area or increasing the number of cannabis grows in the future, and possibly upgrading the lighting system and other equipment, and therefore need an air conditioning system that can be flexibly expanded or adjusted to accommodate these changes.

When sizing and using the room, it is important to balance the current needs of the grow room with possible future changes so that long-term benefits and sustainability can be achieved.

Considering Plant Density and Growth Stages

The density of the plants and the stage of growth they are in can have an impact on the temperature and humidity in the grow room. We will further explore how plant density impacts cannabis HVAC system loads and how system settings can be adjusted to meet the needs of plants at different stages of growth.

Impact of Plant Density on Cannabis HVAC Load

An increase in the density of cannabis cultivation will increase the capacity and performance requirements of the grow room HVAC system. Growers therefore need to consider the amount of growing space each cannabis plant requires when selecting an HVAC system.

Heat and Humidity Generation

Cannabis releases heat during photosynthesis and respiration, and the higher the density of cannabis, the higher the amount of heat released. If the density of cannabis grown in a grow room is too high, it requires a cannabis HVAC system that is capable of removing the excess heat. At the same time, cannabis releases water vapour during transpiration, which also requires the HVAC system's ability to dehumidify. Only by maintaining the right level of humidity can you prevent mould or other humidity-related problems from occurring.

Determining Optimal Plant Density

Finding the right plant density is a process that requires a trade-off between maximising production and ensuring that the cannabis HVAC system can adapt to the environmental load.

If cannabis is grown too densely, it may result in a crowded growing space. The humidity in the growing room will then increase, raising the risk of mouldy cannabis. If cannabis is grown in too small a quantity, it may mean that the growing space is not being fully utilised.

By carefully considering these factors, growers can achieve a balance that increases yields while maintaining environmental stability and plant health.

Adjusting Cannabis HVAC Settings for Growth Stages

Cannabis has different needs for temperature and humidity at different stages of growth, which requires the HVAC system to be set up and adjusted accordingly at different stages of cannabis growth.

Seedling Stage

Seedling cannabis requires relatively high and stable temperatures (around 70-75°F) to promote seed germination and healthy growth. At the same time, seedlings require humidity levels of approximately 65-70% to prevent drying out and promote root development. This requires that the cannabis HVAC system in the grow room have high heating capacity to maintain high room temperatures and high humidification capacity to maintain high humidity levels.

Vegetative Stage

Cannabis in the growing phase requires less humidity than in the seedling phase, with appropriate humidity levels ranging from 40-60%, but higher temperatures than in the seedling phase, which can be elevated to 70-80° F. Cannabis in the growing phase grows faster and requires higher light intensities, which requires the cannabis HVAC system to have higher cooling capacity to remove the heat from the increased size of cannabis and the increased light intensity.

Flowering Stage

When cannabis reaches the flowering stage, humidity control in the growing room becomes especially important. Cannabis in the flowering stage has lower humidity needs, which should be reduced to 40-50% to prevent flower rot and mould growth. The temperature in the grow room should be maintained at 65-75°F during the flowering period, while the night time temperature should be lowered to simulate the natural environment.

By choosing a properly sized cannabis HVAC system that takes into account the density of the plants and their needs at different stages of growth, growers are able to help the plants achieve the right environmental conditions at every stage. This helps to manage heat and humidity levels appropriately, optimising the growing conditions of the plants and is the basis for creating these desired results.

Factoring in Equipment Wet Load

Wet load is the total amount of humidity to be handled by the cannabis HVAC system.

Identifying Sources of Wet Load

The main source of moisture load in cannabis grow rooms is irrigation. The type of irrigation system and the amount of irrigation per plant can have a significant impact on the moisture load within the grow room, as the amount of irrigation can directly affect the moisture content of the soil and substrate, and thus the amount of evaporation and transpiration.

Irrigation Systems

Irrigation systems are an important source of humidity in grow rooms. The amount of water used for irrigation, as well as the method of irrigation - such as drip, flood or hydroponics - all have an impact on the moisture load. Growers need to control water levels appropriately and ensure effective drainage mechanisms. This is because if it is not managed correctly and results in excess water, this will not only increase humidity levels within the grow room, but may also cause mould and root disease.

Plant Transpiration

Cannabis transpiration, the process by which cannabis absorbs water from its roots and releases vapour into the air through its leaves, not only increases the humidity in the environment, but also increases the moisture load on the HVAC system.

Humidifiers

Some growers use additional humidifiers during the seedling and growing stages of cannabis to optimise the growing environment, which directly increases the amount of water vapour in the air and also increases the humidity load on the HVAC, which requires more energy to maintain the right humidity levels. Therefore, growers should consider whether or not they will need to use a humidifier when selecting an air conditioner size, and if so, take into account the humidity load generated by the humidifier.

Calculating Wet Load

Knowing the main sources of moisture load in the grow room, the next step is to calculate the exact moisture load.

Internal Wet Load Calculation

The total daily irrigation volume is usually calculated, then the amount of water produced by evaporation and transpiration of cannabis, and finally all the volumes are added together to get the total moisture load. This can be calculated according to the following formula:

Total irrigation per day: total irrigation = irrigation per plant x total number of plants

Evapotranspiration is mainly the amount of water that evaporates from the soil and substrate surfaces, and is related to the total irrigation volume and environmental conditions (temperature, humidity). Transpiration is primarily related to the growth stage of the plant, leaf area, and environmental conditions.

As an example, there are 100 plants in a growing room with a daily irrigation of 2 litres per plant. The environmental conditions are such that the evaporation per day is 20% of the irrigation volume, the transpiration rate per square metre of leaf area is 0.1 kg/m2/hour, and the leaf area index is 0.5 m2 .

Then the calculation is as follows:

Total irrigation = 2 litres/day x 100 plants = 200 litres/day

Evapotranspiration = total irrigation x 0.2 = 200 litres/day x 0.2 = 40 litres/day

Transpiration = 0.5 m2 x 0.1 kg/m2/h x 100 plants x 24 hours = 120 kg/day

Total wet load = evaporation + transpiration = 40 litres/day + 120 kg/day = 160 litres/day

External Wet Load Calculation

External moisture load refers to moisture that enters the grow room from the external environment, usually through the constant opening and closing of doors as well as structural gaps such as vents during personnel movement.While this type of moisture is more difficult to control directly, it is important to consider this factor when making system designs and calculations. Growers can measure incoming and outgoing air flow and air humidity by installing air flow sensors.

Integrating Wet Load into Cannabis HVAC Sizing

The grower will need to select an HVAC system that can handle the calculated total moisture load, and the dehumidification capacity of the HVAC system is usually expressed in terms of the amount of moisture removed per hour or per day (in litres/hour or litres/day). When sizing you need to consider that the dehumidification capacity of the HVAC system is slightly higher than the calculated total humidity load, in order to cope with changing conditions that may arise.

If you are still confused about sizing, feel free to consult with Altaqua HVAC's technical and service staff.

Calculating Cannabis HVAC Heat Loads

The handling of heat loads is equally problematic in grow rooms. Heat loads usually originate from a number of areas within the grow room, such as lighting fixtures, ventilation systems, and dehumidifiers. Growers who want to choose the right sized HVAC should specify not only the amount of moisture load that needs to be removed from the grow room, but also the amount of heat load that needs to be removed from the grow room.

Identifying Heat-Generating Equipment

To effectively manage the heat load in a grow room, it is first necessary to identify those devices that generate heat. Since the amount of heat generated varies from device to device, the heat output of each device needs to be considered.

Grow Lights

In cannabis grow rooms, plant lights are a major source of heat. This is especially true of high-intensity lighting such as HPS (High Pressure Sodium) and MH (Metal Halide) lamps, which generate a lot of heat while providing light. Even LED lamps, which are known for their high energy efficiency, generate a certain amount of heat.

Ventilation Systems

Ventilation systems include fans and exhausts, and although they are primarily used to regulate air flow and remove excess heat and humidity, their motors and moving parts also emit heat. Growers need to take the heat generated by the ventilation system into account to ensure that the HVAC system they choose can adequately cope with the overall heat load and maintain a stable growing environment.

Dehumidifiers

Dehumidifiers produce heat as a byproduct of removing moisture from the air. This is because the dehumidifier's compressor and fan generate sensible heat as they work, which increases the temperature of the air in the room.

Calculating Heat Output of Cannabis HVAC

The next step is to figure out how much heat the device produces.

Lights and Their Heat Contribution

To calculate the heat produced by grow lights, it is important to know the power of each light, followed by the formula to calculate the total power of the plant lights.Then convert the total power to the amount of heat produced per day. There is generally a calculation formula to refer to:

Total power = power of individual plant lights x number of plant lights

Suppose there are 10 plant lights, each with a power of 600 watts, running for 18 hours a day. Then the calculation process is as follows: Total power = 600 watts/lamp x 10 lamps = 6000 watts = 6 kW

Ventilation and Cannabis HVAC Systems

Growers can estimate the additional heat contribution to the environment by considering the power of fans and exhaust systems and the time they run.

Combined with these heat load specifics, selecting a properly sized HVAC system can help growers better control the environmental conditions inside the grow room. A properly sized HVAC system not only improves energy efficiency, but also significantly improves the overall environmental conditions in the grow room.

Factoring in External Climate Conditions

External climatic conditions can have a similar effect on the internal temperature and humidity of a cannabis grow room. External factors such as seasonal temperature variations therefore need to be taken into account when sizing HVAC.

Assessing External Heat Sources

If a grower only calculates the heat load inside the grow room when sizing the HVAC, then this is likely to underestimate the amount of heat that actually needs to be handled, which will result in the temperature inside the grow room not reaching the target setting. So when selecting an air conditioner you also need to consider the effect of heat sources outside the grow room on the temperature inside the grow room.

Seasonal Temperature Variations

External heat sources such as solar radiation, outside air temperature and humidity can directly affect the temperature and humidity of the grow room. Growers need to be especially aware of seasonal temperature variations. For example, in certain hot summer areas, hot weather outside can increase the cooling needs inside the grow room.

If only the heat load generated by the equipment inside the grow room is taken into account, the HVAC system may not be able to respond effectively when faced with seasonal hot weather, which can lead to higher temperatures inside the room and affect the growth of cannabis.

Building Insulation and Structure

Earlier we discussed that external heat sources can be transferred to the interior through windows, walls and roofs, which in turn increases the heat load on the interior. This is where the performance and structure of the building needs to be considered.

Growers who want to minimise external heat entering the grow room can use good insulation and design, such as double-glazed windows, thick walls and reflective roofing materials. High-quality building seals prevent air leakage and maintain a stable environment within the grow room.

Integrating Heat Load Calculations

Taking all of these considerations into account, the grow room can have a clear understanding of the total heat load that the HVAC will need to handle, and in turn be able to select a properly sized HVAC system.

In this way growers are able to select a properly sized HVAC system that is not only able to cope with current environmental conditions, but also adapt to seasonal changes, providing optimum growing conditions for plants and creating a stable and controlled growing environment.

Work with HVAC Manufacturer to Clearly Communicate Needs

All growers have their own preferences for their grow room environments, so it's best to work with an HVAC manufacturer that has expertise in design when building or redesigning grow room options for HVAC so that the system can be customised to the grower's own preferences and needs.

Communicating Your Needs Clearly

Choosing an appropriate HVAC system for your grow room is a complex process with many variables and influences involved. Growers who want a professionally designed HVAC system to meet current and future growing needs must clearly communicate their growing requirements to the HVAC manufacturer.

Providing Detailed Room Specifications

While HVAC systems are common, less common are engineers who know how to build HVAC systems specifically for grow facilities. Growers need to provide engineers with detailed grow room room specifications when communicating with HVAC manufacturers so they can better provide solutions.Aaron Mullins, systems engineer at NEXT BIG CROP, has said, "To ensure that your HVAC system lasts, it is recommended to determine your current production needs and then build a large 20 percent HVAC system." That's why providing detailed room specifications to the manufacturer is a must.

Sharing Plant Growth Cycles and Conditions

Often times, one may contact engineers who do not have experience in building rooms to the requirements needed in a grow room, so when working with your manufacturer, it is best, though perhaps redundant, to inform the manufacturer of the growth cycle of the cannabis you are growing and the specific environmental conditions required to be required at each stage. Regarding the control requirements such as temperature, humidity and carbon dioxide concentration that are expected in the growing room when the cannabis is in the seedling stage, the growing stage and the flowering stage.

Evaluating Different HVAC Options

HVAC manufacturers may have more than one solution for a grower's needs and requirements, and it's up to the grower to carefully evaluate and compare the options, balancing the immediate needs with the long-term operating costs of the future to select the most cost-effective solution.

Comparing System Efficiency

The energy efficiency ratios of different models of HVAC systems will have a direct impact on the cost of operating the system and its impact on the environment.Prioritise systems with higher SEER (Seasonal Energy Efficiency Ratio) ratings, as they typically perform better and use less energy. Investing in a high-efficiency system will not only reduce your daily utility bills, but it will also help reduce your environmental footprint.

Considering Long-Term Costs

Purchasing an HVAC system can be expensive, and many growers may not be prepared for the cost of an HVAC system at first, and end up choosing the product with the lowest upfront cost due to trying to save money.While the initial investment cost is an important point of consideration, the key to deciding which equipment to purchase is the total cost of ownership. A facility can certainly reduce initial capital costs by purchasing a cheaper solution, but growers will end up with poorly performing equipment that is more expensive to operate and maintain.

While high-efficiency systems are more expensive at the time of purchase, they may be able to save more over their lifespan due to lower operating costs. An in-depth discussion with the manufacturer about these long-term costs will provide a more complete picture of the system's total cost of ownership.

Balancing Cost-Effectiveness and Optimal Environmental Control for Your Project

To create the perfect cannabis grow room environment, you need to rely on a properly sized HVAC system. And system selection is a process of balancing between cost-effectiveness and optimal environmental control.

Designing Cannabis HVAC Systems with Professional Hvac Engineers

Team Altaqua is a specialist HVAC equipment manufacturer with over 15 years experience in the refrigeration industry. With a wealth of expertise and a flexible, customised service, we are able to respond quickly to our customers' needs and provide reliable technology. Our professional team can help you deal with the complexity of HVAC design, from the setup of the moment to the planned expansion in the future, we will provide you with the best solution.

Using Calculations for Cannabis HVAC System Sizing

A key metric that growers often fail to decide on when purchasing an HVAC is that lighting intensity, expressed in watts per square foot, can have a significant impact on the size of an HVAC system, and may not be aware that airflow is determined by equipment capacity rather than room volume, and that manufacturers often need to go through a series of calculations to ultimately determine the right equipment size and capacity.

Altaqua's dedicated HVAC team will provide you with a tailored solution based on your specific profile, so you have a trusted resource throughout the lifecycle of your grow, from planning and implementation to maintenance and optimisation.

Understanding Manufacturer Recommendations

Based on detailed calculations and analyses, we will recommend several suitable HVAC system options for you. The systems we recommend are capable of handling all heat and moisture loads and are energy efficient to reduce long term operating costs. Our team is committed to customer satisfaction, striking a balance between your requirements and recommended solutions to increase production and efficiency while reducing operating costs.

Customizing Solutions for Your Grow Room

Our aim is to be a partner to our customers, not just a supplier. We are willing to offer advice based on our experience and hopefully help solve your problems. Not all solutions are created equal when it comes to creating the perfect grow room. Just as master growers know their plants, we know our equipment, and it takes both parties to create the perfect cannabis grow room. We are sure to strike the perfect balance between cost-effectiveness and optimal environmental control.

Conclusion

In this blog, we will cover the importance of properly sizing an HVAC system in terms of its impact on energy efficiency, cannabis health, and overall operating costs.

By taking into account the density and stage of cultivation of cannabis in the grow room, as well as the total heat and humidity that needs to be removed, we can more accurately size an HVAC system to optimise the conditions in the grow room and improve yield and quality.

Additionally, working with a professional HVAC manufacturer like Altaqua ensures that your specific needs are met. By providing detailed room specifications, as well as the growth cycles and environmental conditions required for each stage of cannabis cultivation, Altaqua manufacturers are able to tailor a solution for your grow room through careful calculations and modelling. Different HVAC options are evaluated based on efficiency and long-term costs, ultimately striking a balance between cost-effectiveness and optimal environmental control, resulting in greater profitability.

FAQ

1.What is the optimal temperature and humidity for cannabis grow rooms?

The optimal temperature and humidity in a cannabis grow room varies depending on the different stages of cannabis growth. At the seedling stage, the optimal temperature is around 70-75°F and the optimal humidity is around 65-70 per cent. During the asexual reproduction stage, it is best to raise the temperature to 70-80°F and lower the humidity to 40-60%. During flowering, optimum temperatures should be maintained at 65-75°F and humidity at about 40-50% to prevent mould and promote healthy bud development.

2.How does plant density affect the HVAC system in a cannabis grow room?

If the density of the plant is high, then the amount of water and heat released will increase, at which point a more robust HVAC system will be required to manage the increased compliance in order to maintain optimal growing conditions.

3.Why is it important to correctly size an HVAC system for cannabis cultivation?

This is because an oversized HVAC can lead to short cycling, energy waste, and uneven temperature and humidity control, while an undersized HVAC may struggle to maintain the desired conditions leading to fluctuating temperatures and humidity, resulting in lower cannabis yields and potential problems such as mould.

4.How can I calculate the heat load for my cannabis grow room?

To calculate the heat load for your cannabis grow room, consider the heat generated by grow lights, ventilation systems, dehumidifiers, and other equipment. Start by determining the power consumption of each light and piece of equipment, then calculate the total heat produced.

5.How do I determine the correct size of an HVAC system for my cannabis grow room?

The following factors should be considered when selecting an HVAC system for a cannabis cultivation room: the size and layout of the room, the density of the plants, the type of lighting and the specific environmental control needs of the different growth stages. Factors such as heat and humidity loads, insulation quality and temperature should also be considered.

Altaqua HVAC · Maximising Yield With The Perfectly Sized Cannabis HVAC System