FAQS

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Most Asked Questions

  • Ceres provides a precision controlled environment, which leads to higher yields, less crop loss, lower operating costs, better quality product and healthier plants in general.
  • Ceres’ designs are the most energy efficient, offering a lower carbon footprint, as well as lower operating costs.
  • Ceres uses materials that are durable, ensuring the longest possible life for the greenhouse
  • Ceres cares about the success of the customer, ensuring technical support throughout the build and even long after during greenhouse operations.  
  • The modular greenhouse design allows for both easy expansion and complete biosecurity.
  • Data driven standard kits or customizable designs are options.

This varies by your climate and your desired indoor growing temperatures. (An energy-efficient greenhouse has a much greater payoff if you need a warm, year-round growing environment and / or have very harsh climate). We can provide an energy analysis to calculate your energy savings, or provide more information on energy savings if you send us an email with your location and growing goals.

Check out our new energy calculator to get an approximate on your savings!

Our data indicates an expected approximate of .78 lbs/ square foot of canopy/ year in a sealed greenhouse.

Ceres energy-efficient greenhouses range in cost from $30 to over $200 per sq. ft. We provide custom quotes for our greenhouses because every project is slightly different. Several factors influence cost, including:

  • Size. Larger greenhouses have a lower cost per sq. ft.
  • Whether pursuing a custom design
  • Whether you need a building permit (requires stamped structurally engineered plans, which we can include)
  • The growing and climate control systems you are adding

Because each greenhouse is slightly different, we work with you to find the best, most cost-effective method of building for your needs. Please contact us for a free quote.

The structure is the same. The main difference is how we heat/ cool/ and dehumidify the structures as well as which glazing we chose to use for light transmission.

You get all the advantages of an indoor grow- total control, predictability, and year round growing with the advantage of full spectrum sunlight for better quality product. And lower operating costs than an indoor grow. 

Yes, we provide tours of our residential and commercial greenhouses in the Boulder / Denver area in Colorado. If you are in that area, we would be happy to take you for a tour to see in person how an energy-efficient commercial greenhouse looks and operates. Please contact us to schedule a tour.

GAHT™ System / Climate Battery Questions

“Geothermal” is a broad term meaning heat from the earth. The term applies to many systems, including heat pumps and power plants using hot steam from the earth. GAHT™ systems are geothermal too: they use the ‘low-grade’ heat provided by the shallow earth. But, a GAHT™ system is NOT the same as a geothermal heat pump, a system commonly used to heat homes and commercial buildings. Heat pumps are more complex systems that use a refrigeration cycle. They circulate a fluid, not air, underground, and use pipes buried very deep — often hundreds of feet — underground. A GAHT™ system, in contrast, simply uses a fan and pipe to transfer heat to the soil. GAHT™ systems store heat in an insulated volume of soil, usually just 4′ below grade. They are much simpler, less expensive than geothermal heat pumps.

For the most part, yes. Ceres’ Ground to Air Heat Transfer (GAHT™) systems and climate batteries are both ground to air heat exchangers.  Over the years, different designers have given the system their own names based on their design.  Jerome Osentowski and Michael Thompson of the Central Rocky Mountain Permaculture Institute (CRMPI) coined the term Climate Battery. At Ceres, we altered the fan sizes and pipe configuration based on our research and call the system a GAHT™ system.

Another similar concept is earth tubes, often called a ground-coupled heat exchanger. These use one-way air flow: they draw air in from outside, pump it underground and then it into the structure (home or greenhouse). A GAHT™ system and Climate Battery circulate air in a closed loop: they take air from the greenhouse, pump it underground, and then exhaust it back into the greenhouse.

The cost of a GAHT™ system depends on the size of your greenhouse. Typically, residential GAHT™ systems (under 1,000 sq. ft.) cost between $2,000-5,000. Larger commercial greenhouses and school greenhouses typically cost $5,000-$15,000 depending on size.

Our GAHT™plans provide detailed installation instructions for building and installing a GAHT™ system. Here is an overview of the process:

  • Excavate a pit beneath the greenhouse (before greenhouse construction)
  • Build and install the underground pipe network in the excavated pit
  • Back-fill the pit. Then construct greenhouse. See our residential building plans for help
  • Install fans and wiring inside the greenhouse

For our residential greenhouses, we provide plans, materials lists and instructions for installing a GAHT™ system. Armed with these tools, you can install the GAHT™ system yourself or easily hire out the work to a contractor. We also provide phone support to answer any question that may come up along the way.

Yes, we can provide all materials for the GAHT™ system, including underground pipes, pipe connections, fans and thermostats. A material list is included in our GAHT™ plans and instructions. Some growers prefer to purchase the materials on their own; other prefer to have us order and ship them, and pay all at once. Please contact us for a personalized quote your GAHT™ system.

Maximum depth for the pipes underground is 4’ deep. This is below the frost line in most climates, and the level where soil temperatures become a stable and moderate temperature year-round.

In locations where the water tables is higher than 4’, we do not recommend using a standard GAHT™ system. Other heat storage methods, like phase change material can be used to make your greenhouse as energy-efficient as possible.

The pipes of a GAHT™ system have small perforations so any water that collects in the pipes underground can drain out into the soil. Water plays in an important role in how GAHT™ systems function. During the day, hot humid air is cooled underground. The temperature reaches the dew point and water condensates in the pipes underground. Through the energy transfer of phase changes, this further cools the air. It also helps water the soil underground, where plants roots are. Essentially, the GAHT™ system takes water out of the humid greenhouse air and drops it into the soil underground where it’s useful for growth.

Water does not stagnate in the pipes underground and so mold is not a problem in GAHT™ systems. In many years of testing systems in a variety of climates, we have not experienced any issues relating to mold.

Yes, GAHT™ systems can function in any type of greenhouse. We recommend using an energy-efficient greenhouse, however. It is by far the most cost effective investment when creating a year-round growing environment.

Radon is a radioactive element that seeps into buildings through the soil. Since a GAHT™ system circulates air directly through the soil, a common question is whether the GAHT™ system adds a radon risk. In areas with high radon levels, this is a possibility and should be taken seriously. However, greenhouses are less dangerous than conventional buildings when it comes to radon. First, you are not in the greenhouse for as much time. Secondly, greenhouses have very high air exchange rates. During much of the year, air (and any radon) will be ventilated outside, and the whole structure will be flushed with fresh air in a matter of minutes. Even if the ventilation system is not on, greenhouses have many more air exchanges than a standard home, mitigating radon build-up. In our tests of GAHT™ systems in the Rocky Mountains (an area with high radon levels), the concentration inside the greenhouse was found to be slightly higher than outdoors, but much lower than a dangerous level. By no means is this a comprehensive study, so if concerned, have your soils tested for radon before installing a GAHT™ system.

Small GAHT™ systems can be off-grid if you install a solar panel system. We do not provide integrated solar panel systems with GAHT™ systems. Solar panels should be installed by a local installer in your area, or on your own if you are qualified.

A solar PV system can be a few thousand dollar investment, which greatly depends on the electric demand of your greenhouse. As an example, a 12 x 20 greenhouse normally includes 2 GAHT™ fans, each 120 Watts. Along with exhaust fans, we estimate this greenhouse would have an energy usage of 1,000 kWh per year. In a sunny climate like Colorado, this could be powered by a 600 Watt solar panel system. At current prices (roughly $3.00 per installed Watt) this would cost $1,800 to the greenhouse project. Please note this is a rough estimation based on a typical greenhouse and solar PV system. For a more accurate estimate and to discuss the practicality of powering your greenhouse with solar PV, please contact us

To date we have never installed a house GAHT™ system. This does not mean it is not possible. We just have not installed one. Before considering this option there are two concerns you should be aware of: 

  1. Radon 
  2. Mold

Radon can be tested. And even if there is radon, it is more significant to watch the rate at which it accumulates. In the worst case scenario, if radon is detected the GAHT™ system can always be shut off. 

According to studies that were performed by the University of Minnesota on several GAHT™ systems where mold was tested no elevated spores were detected. It is important to keep in mind this is one study, and they were conducted on greenhouses and not homes. 

When trying to mitigate mold in the home you could use a filtration system with a UV lamp. It is important to look at ducting system- how to get air through the system. We can help with the design of a new system, but it is harder to work with existing ones.

Understanding these precautions is necessary if you decide to try this system on a house. Please consult us if you are thinking of a house GAHT™.

Commercial Greenhouses

We provide tailored quotes for commercial greenhouses, as each structure is optimized for the climate and growing considerations. Pricing varies according to structure type — commercial HighYield™ Greenhouse Kits – as well as your indoor growing requirements and climate. Please contact us with some information about your project to get a quote.

Our commercial energy-efficient greenhouses are made with galvanized steel frames. Steel is the strongest framing material, and can be insulated in a variety of ways. We combine the frame with insulated metal panels, commonly used in warehouses or large industrial buildings, because of their high insulation values and ease of install.

We offer acrylic, ETFE, or polycarbonate as glazing options. To learn more about which option might be best for you check out our blog on how to choose a glazing material for your greenhouse. Factors in decision making include:  budget, location, and what you are growing for (i.e. THC or CBD). 

Our typical commercial greenhouse is a shed-style roof with a single slope as the gutter connect design is not optimal for light harvesting. Our modular approach also allows for the unlimited expansion with uninterrupted workflow and biosecurity. Light deprivation curtains also do not function as well with a gutter connect design. 

If this does not fit your site, or in cases of very large (over 5,000 sq. ft.) commercial greenhouses, we can employ alternate building styles. In any case, we work with you to create a custom structure that meets your needs, site and budget.

Our HighYield™ Greenhouse Kits use two building depths – 23’ and 30’ – and can be as long as needed. Our custom commercial steel greenhouses are more flexible in sizing and layout, and are typically used for greenhouses with a minimum square footage of 4,000 square feet. We have in-house drafters who can draw any custom building based on your design criteria.

We custom engineer each structure according to your site’s snow and wind loads. This streamlines the building permit process, which we can also help with. We have designed greenhouses with snow loads of up to 85 lbs/square foot, and with wind loads of up to 135 mpg.

At Ceres we focus on building the most energy-efficient commercial greenhouses as possible. Our primary HVAC system, known as the Ecoloop™ system offers precision temperature, humidity, and vapor pressure differential control.

We are well-known for our GAHT™ system, a Ceres designed ground to air heat exchanger, which we have designed for many years all over the world. Finally, by using passive solar greenhouse design principles we minimize the heating / cooling load as much as possible, making our commercial greenhouses much easier to regulate and much more cost-effective versus traditional greenhouses. We also integrate back-up heating, cooling and ventilation systems as needed.

Like many commercial greenhouses, we often install gas powered heaters, dehumidifiers, and exhaust fans. Oftentimes, because of the built in efficiencies of our greenhouses and smaller heating and cooling loads that we deal with, we can design smaller systems to save our clients money during initial installation, and because the systems are needed less often, they save money over the long term.

We are also leaders in designing light deprivation systems as well as shading systems, and work with industry leaders to incorporate their systems into our highly efficient greenhouses.

Yes. We source growing systems and equipment from high-quality suppliers, according to your needs. These include:

  • Hydroponic and aquaponic growing systems
  • Black out / light deprivation systems
  • Shade systems
  • Irrigation systems

You can see some of the companies we work with on our partners page. We work directly with suppliers to ensure that growing systems integrate seamlessly with the greenhouse structure, handling all the planning and details for you.

Our whole systems approach to design ensures that all of the systems you need for your grow operation are integrated into the design process.

Building a commercial steel greenhouse like our HighYield™ Greenhouse Kits requires some construction experience. A skilled crew of 3 with a scissor lift can put up the steel frame, IMPs, and glazing. We recommend specialists for concrete work, electrical, plumbing, mechanical, etc. 

While we do not build the greenhouses ourselves, we do have a dedicated building crew that can offer remote support. We also offer site visits, with adequate notice, that can help train crews. Contact us for more info. 

Yes, we offer our own renewable heating/cooling system, as well as other climate control and growing systems.

Growing systems are customized according to growers’ needs, and specified after a consultation. Every grow system has its merits. It’s important to consider available labor and knowledge when selecting a grow system. This decision is also dependent on local laws dictating the use of pesticides and synthetics. Check local laws and regulations for compliance.

Ceres can size, design and source:

  • Hydroponic and aquaponic systems
  • Light deprivation systems
  • Supplemental lighting, automated shade systems
  • Climate control and HVAC equipment
  • Monitoring systems

It depends on what you are growing the hemp for.  If you need to flower the plants inside the greenhouse, then light deprivation is needed.  This includes breeding and growing for flower. If you are only using the greenhouse to house mothers, cut clones, or start seeds, then light deprivation is not needed as these are all vegetative growth environments requiring 18 hours of light per day minimum.

Sometimes, permitting counties do not allow lights to run in a greenhouse when its dark out, so if you do need to maintain 18 hours of light in your greenhouse throughout the winter, then light deprivation may be necessary to hold light inside the greenhouse.

Greenhouse Kits

Easy shipping anywhere in the US and Canada. If you are elsewhere please contact us for a shipping cost estimate.

You can install a HighYield™ Kit yourself, or hire installation out to a local contractor. You can also opt to have a Ceres construction supervisor oversee the construction process and direct your building crew.

This depends on your level on construction experience. Assembling a HighYield™ Kit requires significant construction experience, and a crew of at least 3 people. You can get a sense of the steps needed to build a HighYield™ kit from our video. The following equipment and tools are required to install a HighYield™ Kit:

  • Riveter
  • Hammer drill
  • Boom lift with forks and cage
  • Circular saw with metal blade
  • Corded impact driver

If you have experience with those tools, you can probably build a HighYield™ Kit on your own. We still recommend hiring one of Ceres Construction Managers to assist with the process.

Because each greenhouse is slightly different – tailored for your climate and growing goals—we provide custom quotes for all our energy-efficient commercial greenhouses. Pricing starts at $35 per sq. ft. for un-installed greenhouses. Please contact us to start a custom greenhouse quote.

Foundation & Floors

Yes. The next question is whether to use gravel or concrete slab. We recommend a slab with a drain because it is easier to clean.

Solar Panels, Electricity and Water

There are too many variables to give an easy answer to this question. The top two are:

  • What are you trying to grow, or what indoor temperatures do you want to maintain?
  • What are you typical outdoor temperatures in the winter?

Once we have that information, we can give you a ballpark estimate of how often heat will be required for your situation. For a more accurate estimate and cost projections, you can take advantage of our consulting services.

The Ceres Ecoloop™ geothermal system utilizes earth’s steady temperature to provide a sustainable and year round source of heat, greatly reducing energy costs. One can expect 40% savings compared to a standard HVAC system.

Finally, it is important to note that an insulated greenhouse, passive solar greenhouse design, and systems like a GAHT™ system, which take advantage of free solar energy, keep the heating requirement to a minimum. Most growers in North America use back-up heating sparingly in the winter, and rely on energy-efficient greenhouse design for most of the year.

This varies greatly by location, and what you are trying to grow. In areas with mild winters, passive solar greenhouses can grow year-round without any back-up heating. However, to grow a wider variety of crops, in most cold climates an energy-efficient greenhouse will require some back-up heating. This is usually turned on during a few very cold nights a year — the extreme cold snaps — when a GAHTTM system.

Our innovative geothermal Ecoloop™ System can provide all of the heating, cooling, and dehumidification for your greenhouse. Please contact us for more information on the Ecoloop™.

It depends. Is your greenhouse vented or sealed? Vented requires less energy to run heating/ cooling. Test our new energy calculator to see how much energy you might consume with a sealed system. Or read about the differences between vented versus sealed here.  

You can also build a completely passive solar greenhouse – one that does not use any electrical components. However, if you are planning on growing for commercial purposes, we would recommend using electricity.

It depends on the size of your greenhouse, the systems you are using, types of lights, and whether you are using extraction equipment. A single sealed greenhouse without extraction would use approximately 700 amps.

Our greenhouses utilize passive solar design, called ‘solar greenhouses’ for short. Passive solar greenhouses are designed to maximize heating from the sun, to create an efficient self-sustaining year-round growing environment. While they can be powered by a solar PV (solar panels), Standard models do not include solar panels (photovoltaic systems). We can help you integrate solar panels into your design and recommend putting them on the headhouse to not interfere with greenhouse design and shading. Please reach out to inquire about potential rebates and financing.

Sustainability and energy efficiency are pillars of our design philosophy. We are happy to explore whether this is a potential to integrate into your design however it is site specific and also considered custom work.

Ecoloop™ Geothermal System

The Ceres EcoLoop™ is a hybrid Ground-Coupled-System, which is commonly known as a geothermal system in the United States and a Ground-Source-Heat pump in Europe. The Ecoloop™ is thus an innovative geothermal system designed specifically for Greenhouse Controlled Environment Agriculture.
Some of the unique advantages over a conventional geothermal system are the system’s resilience, redundancy, modularity, heating and cooling load capacities, and it’s low environmental impact. Additionally, the Ecoloop™ system requires minimal invasiveness to the earth (the system sits 6′ below grade, opposed to the 400′ bore holes of traditional vertical geothermal systems). 
Contact us to learn more.

The Ecoloop™ system is engineered for each client’s specific requirements. Cost is calculated based on such factors as: different climate zones, size of grow operations, etc. The Ecoloop™ has been designed as an affordable geothermal system while still delivering efficient high performance. Payback on this system is roughly one year. Material costs for installation range from approximately $50-65/sqft. The EcoLoop™ system may qualify for a multitude of rebates because of it’s energy efficiency rating. 

The Ecoloop™ system installation involves below grade and above grade work. This can be completed by the same contractors or two different contractors. Below grade contractors should be IGSHPA (International Ground Source Heat Pump Association) certified installers. Ceres can provide installers for this work worldwide. Above grade work can be completed by local HVAC contractors or the same contractor.
Ceres has a network of highly trained professionals for installation of the Ecoloop™ system that we can connect our clients to for providing installation services. 
Contact us for more information
The Ecoloop™ is a closed loop system. Water injected at startup continuously circulates in the closed ground loop and through the heat pumps to transfer heat between the grow spaces, the ground and the outside environment.

The Ecoloop™ has been optimized for maximum efficiency and performance using specific controls, operating parameters, and smart responses to changing conditions in a Ceres greenhouse. Ceres is only installing the EcoLoop™ in Ceres Greenhouses through the end of 2020.  

Yes, the Ecoloop™ system can be run using renewable sources of electricity. The Ecoloop™’s design reduces the peak demand load as compared to other HVAC options, helping reduce the overall size of the energy generation system.

There are major differences between the two systems, and they can’t be compared to each other.  The GAHT™ system is a lower tech air-to-ground heat exchanger, which can’t deliver specific temperatures but can help with some heating and cooling, reducing peak loads and overall operational costs.  The EcoLoop™ is a much more robust mechanical HVAC system, which provides complete cooling, heating, and dehumidification based on specific set points and controlled by Ceres’ Unity Smart Controller.
 
Two deciding variables for choosing between the GAHT™ and Ecoloop™ system are: 
1. Precision required for environmental control: Ecoloop™ can control environmental parameters within 5-7% of the requirements. The GAHT™ is a great option for a vented greenhouse environment, whereas the EcoLoop™ is optimal for a sealed grow environment
2. Budget: Initial startup cost for the Ecoloop™ is about 2-3 times more than a GAHT™ system

Design & Construction

A year-round solar greenhouse needs access to light particularly in the winter months. Areas that allow sufficient year-round light, with minimal shading in the winter are best. More of our recommendations are given in our blogs on the topic:

No. We engineer our greenhouses to exact specifications. As quality design and energy efficiency are of primary importance to have as tight an envelope as possible.

From excavation to final inspection one can expect 3-4 months until the greenhouse is built. Factors that affect this timeline include size, complexities in design and systems, building permits, and availability of local construction labor. 

Yes. This is considered custom work and will be reflected in the cost. The ability to attach to an existing structure will be dependent on specifics related to the existing structure. It is, however, easier to attach to a corridor than an actual greenhouse.

We opt not to design in this fashion as it creates challenges in humidity management.

Yes it is possible, but it will cost more. The insulated metal panels (IMPs) we use have similar R value to the earth so building into a sloping hill will not necessarily increase the insulation value. Building the retaining wall will also add an additional cost. 

Many solar greenhouse designers recommend using a roof angle that is perpendicular to the angle of the sun in the winter. While this does indeed maximize light transmission in the winter, the effect of a lower angle is not severe. We explain this relationship much further in our blog, Choosing the Best Roof Angle for your Greenhouse. Furthermore, there are a few logistical challenges to creating very steep pitch — you cannot use glass view windows on the south; it can reduce head room or create a awkwardly tall greenhouse. Due to these pros and cons, most of our residential growers are built with a shed-style roof. If you have a need for a steeply pitched roof, just ask us about our custom greenhouse design services.

Tell us about your project.