SunHaven Module: an Affordable, Net-Zero, Passively Heated/Cooled, 3D Printed Housing Solution

Hello! I am a rising junior at Rossview High School in Clarksville, Tennessee. I love everything engineering, and I especially love using CAD to solve problems. I have been using Instructables for a long time, both for creating things that I have found cool on here, and for inspiration for my own projects. I recently discovered that there were competitions on this site, and was eager to check them out.

I had been tinkering with CAD software for a bit, when I discovered this contest, and thought it would be a perfect place to showcase and test my skills.

I came across the problem of energy burden, with my involvement in the YMCA Youth in Government, and YMCA of the USA Changemakers program. From this I learned that energy expenditure is significant for many parts of rural Tennessee, and in other states in Appalachia. I had been thinking about what can be done to alleviate this issue for a few months, and seeing this competition, I knew that it would be perfect.

After a long journey of development, I'm proud to present this project.

Table of Contents

Research: Step 1-13

Planning: Step 14 & 15

Sketching: Step 16-23

Revit: Step 24-34

Fusion 360: Step 35-44

LEED Certification: Step 45-47

Physical Model: Step 48-63

Final Words: Step 64

Credits: Step 65

Notice: These are the supplies used for rendering; the supplies for the 3D prototype will be listed later.

Physical

1. Pencils
2. Papers
3. Colored pencils
4. Ruler
5. Eraser

Software

1. Autodesk Revit
2. Autodesk Fusion 360

For documenting

1. Smartphone/Camera

I live in Tennessee — a state known for its music, mountains, and all else associated with the south. But behind all that, there’s a quieter crisis: energy insecurity. During the colder months, especially in Appalachia and rural areas, too many families are forced to choose between heat, food, or medicine.

Tennessee ranks near the bottom of the country in energy affordability. What really stuck with me was from a 2025 ThinkTennessee report:

Energy insecurity has become the quiet emergency in our state — and the burden is heaviest on the people who can afford it least.

That hit home.

I began researching how housing design could help tackle this — not just with better appliances or solar panels, but by fundamentally rethinking how we design and build homes for energy efficiency from the ground up.

Sources: Think Tennessee

Tennessee Housing Development Agency

Tennessee Department of Environment & Conservation

In most of Tennessee, low-income families live in older, drafty homes. These structures leak heat in the winter and trap it in the summer. Utility bills skyrocket, sometimes exceeding 30% of a household’s income — triple the national average energy burden.

Here’s the reality:

1. Over 400,000 households face “high” or “severe” energy burden.
2. State assistance programs like LIHEAP or Home Uplift only reach a fraction of those in need.
3. The cost of energy is often unbearably high due to lack of energy grid infrastructure.
4. In the current state it is simply too costly/too inefficient to get energy to rural houses in TN, hence the high energy burden.

ACEEE's 2017 report summarized it:

In parts of rural Tennessee, the choice between heating your home and feeding your family isn’t rare — it can be the norm.

This is not just a comfort issue. It's about health.

Source: American Council for an Energy-Efficient Economy

American Legislative Exchange Council

Passively cooled home in Germany

Source: BobVila

I started by searching through techniques used in other parts of the world to save energy on heating and cooling, namely in places that have historically had to develop ways of defending against the cold, and where energy is more expensive than the US.

I came across several such techniques, and was impressed by how simple some mechanisms were. Even further, I was impressed by the fact that houses passively heated and cooled houses look and function in most other ways just like traditionally heated and cooled houses.

I started by visiting ResearchGate, and looking through any publications relevant to passive heating and cooling, saving energy, and cheaper construction. After narrowing these down, I sorted by methods that are cheap to install and don't aesthetically detract from the house. Realizing that these concepts would be hard for me to grasp together, I started by breaking them apart and researching them individually.

Diagram showing how Solar Chimney functions.

Source: University of Calgary

A solar chimney is a tall hollow construction that uses the sun’s heat to move air. As the sun warms the chimney, the air inside gets hot and rises. This pulls cooler air into the building from below, helping to keep the space cool and fresh without using fans or electricity.

Diagrams showing Trombe wall's functions at night vs during the day

Source: Image source removed from internet (Error 404)

A Trombe wall is a thick wall that absorbs heat from the sun during the day and slowly releases it into the building at night. It usually has a dark surface and a glass panel in front to trap heat, like a greenhouse. This helps keep the inside warm without using heaters.

Diagram showing how overhang is used with a Trombe wall to keep a house warm in winter and cool in summer.

Source: University of Calgary

An overhang is a roof or shade that sticks out over windows or walls. In the case of Trombe walls, it blocks the high summer sun to keep the building cool, but lets in the low winter sun to warm the space. This helps control temperature naturally through the seasons.

Solar Panels in Northern Hemisphere facing South.

Source: Forbes

For a house that makes energy cheaper, I already knew that solar panels were a must. However, I did not know the most effective way of positioning them. I learned that the way to position your solar panels depends on where you are.

As a general rule:

Solar panels should face the equator—south in the northern hemisphere and north in the southern hemisphere. The most effective tilt angle is usually close to your latitude. To improve efficiency, tilt the panels 15° more in winter (sun is lower) and 15° less in summer (sun is higher). This setup helps capture the most sunlight year-round.

If the tilt can’t be changed, set the solar panel angle equal to your latitude. This gives the best overall performance year-round by balancing winter and summer sunlight.

Upon further research into materials for the house to be built with, I came across 3D printed housing.

Common materials include:

1. Cement-based concrete: The most popular, often reinforced with fibers to improve strength and reduce cracking.
2. Mortar-like mixes: Thinner than regular concrete, allowing smooth, layer-by-layer extrusion.
3. Additives: Like fly ash, slag, or plasticizers to improve flow, setting time, and durability.
4. Insulating foams or polymers (less common): Sometimes used for interior walls or insulation layers.

This is important, because cement-based concrete has a high thermal mass.

Sources: 3DRIFIC

COBOD

EcoHome

Diagram showing high thermal mass flooring being used to keep house warm in winter and during the night, and cool during the summer and daytime

Source: Australian Government YourHouse

Using 3D printing, due to the high thermal mass of what it uses, allows for further passive temperature management within the house. Additionally, this is useful, because for a Trombe wall to function, high thermal mass construction materials are required.

(Old) Idea of 3D Printed Houses (Flat roof, beveled edges, one story)

Source: ArcTern Ventures

Up till now, I was under the impression that 3D printed houses would be unable to be multiple stories and always had to have round edges, and flat roofs.

Upon further research, I learned that more modern 3D printed houses can be made multiple stories, have any roof type, as well as have sharp edges.

Images showing 3 new improvements to 3D printed homes: Hybrid Prefabricated-3D Printed homes, Multi story 3D printed homes, and 3D printed homes with sharp edges.

Sources: 3D Printing Industry

Archdaily

Gira Magazine

Through this research, I became confident that I could create a house that could address all of the energy needs of Tennessee while also looking aesthetically appealing, cheap to construct, fast to deploy, and conserving space (as much as all of these can be balanced).

Diagram showing how windows are used for passive heating/cooling

Source: Fity

In continuing my research into passive and sustainable energy solutions, I learned that windows play a key role in passively cooling the house during summer. Summers in Tennessee are very warm, so the number of windows in the house and where the windows are to be placed needs to be carefully thought through.

So, I asked: What would a house look like if it was designed specifically to fight energy poverty?

After having researched these methods, I came up with a solution.

The answer became the SunHaven Module — a compact, modular, 2-story condominium-styled home designed to:

1. Capture free energy from the sun in winter
2. Ventilate naturally in summer
3. Run on minimal active energy systems
4. Be built off-site and with 3D printing for cost savings and rapid deployment
5. Have enough space to house up to 2 families.

The SunHaven Module is not a luxury eco-home — it's a practical, scalable model for Tennessee’s rural working-class families.

In short: It tackles two problems at once, the high cost of housing and the high energy bills faced by rural families in Tennessee.

While I feel that most of rural Tennessee would benefit from this house design, some parts are better suited than others.

Counties in Tennessee that are a best fit for SunHaven (in no particular order):

1. Campbell County
2. Scott County
3. Hancock County
4. Clay County
5. Fentress County
6. Jackson County

Why these counties?

1. Part of the Appalachian Highlands region.
2. Documented as having some of Tennessee’s highest energy burdens.
3. Underserved by major utility assistance or weatherization programs.

Source: Environmental and Energy Study Institute

This housing solution is primarily catered towards Tennessee, but it will also work in the following states (and due to the following reasons):

Kentucky – High energy burden in rural Appalachian communities.

West Virginia – Widespread energy poverty and outdated housing infrastructure.

Arkansas – Low-income rural areas with high utility-to-income ratios.

Mississippi – Extreme housing affordability issues and poor insulation in homes.

Alabama – Rural regions face high summer cooling costs and poor access to energy upgrades.

Missouri – Rural families experience severe winter heating costs.

North Carolina – Western counties have aging homes and limited energy assistance access.

South Carolina – Inland areas struggle with inefficient homes and summer cooling bills.

Indiana – Southern Indiana has high utility costs in older, rural homes.

Oklahoma – Energy insecurity driven by rural isolation and extreme weather swings.

Sources: The Department of Energy (DOE)

American Council for an Energy-Efficient Economy

The Department of Energy (DOE)

Tennessee homes

Credit: Houzz

When roughly sketching my design, I wanted to ensure that it looked nice and would be both comfortable and aesthetically pleasing (in addition to affordable). In creating a sketch outline for this design, I wanted to ensure that the following was implemented in my design:

Site & Community

1. Can be integrated into rural TN counties with high energy burden

Aesthetics

1. Designed based on common/traditional houses in Tennessee
2. Adapted for weather and climate of Tennessee (& other Appalachian states)

Climate-Responsive Design

1. Passive heating (Trombe wall, overhangs, thermal mass)
2. Passive cooling (solar chimney, air pathways)
3. Optimized window placement

Energy & Sustainability

1. Solar panels with optimal tilt for latitude
2. Net-zero capable structure
3. High thermal mass construction (3D printed concrete)
4. Low operational costs

Affordability & Construction

1. Modular & prefab design
2. 3D printed (for reduced labor + waste)
3. Adaptable for mass deployment

Scalability & Replication

1. Works across Appalachian states

Safety & Comfort

1. Natural lighting and ventilation
2. Logical layout with privacy for (up to) two families

Community Benefits

1. Reduces energy poverty

Now that I have done enough research to put together a concept, I decided to start by drawing out the house. I find it easier to model things in 3D, if I have a 2D reference.

I started with a rough sketch to outline my idea. I additionally decided on adding a fenced backyard to house the 'solar tube' to increase natural cooling as outlined in Step 5.

I then added shading to the 2nd floor's overhang, and showed how the sun hits the solar roof, and the cavity in the ground for hot air to push cool air into the house.

I then added color, to show what air is hot and cold, as well as which way it goes, as well as the tube inside the house connected to the one outside to cool the house.

I then added a key and started labeling.

I then added more labels, and made it more clear that the tube outside the house is in the backyard, and that the other tube is indoors.

I then added more labels, and incorporated an idea I had: both tubes would be netted and have a closable lid, to make sure nothing accidentally falls in.

Finally I added dimensions, by referencing the average family sizes in Tennessee and how much space is required to house up to 2 families.

Sources: US Census Bureau

World Population Review

With the design finalized on paper, I moved on to bringing it into the digital world using CAD. Since the ultimate goal was to 3D print the structure, having precise and detailed CAD models was essential. I had experience with Blender and Autodesk fusion, but I wanted to try something new. While browsing the Autodesk tools online, I came across Revit: an industry-standard software widely used in architectural design.

I was pleased to find that this software, like Fusion 360, had a student license available.

I started by creating my first floor according to the dimensions I had sketched out.

I then added a door and a large window in the 1st floor, mainly to look aesthetically pleasing, and the window is in accordance with Step 13's passive heating/cooling window positioning guide.

I then designed the layout for the first floor. Keeping in mind to leave open wall space for windows to allow air to circulate. (Labels can be seen by clicking image 2 & 3)

After creating a floor, and walls for the 2nd floor, I added windows to the first floor. Again, I was careful to follow Step 13's passive heating/cooling window positioning guide.

I then went ahead and designed the layout for the 2nd floor. (Labels can be seen by clicking the image)

I then added 2 columns in the front to support the overhang.

I then added a roof with an overhang.

To add the overhang, simply add a value to this button when creating the roof.

I then added the solar chimney, to the kitchen in the 1st floor, and the master bedroom in the 2nd floor, both places likely to have high heat buildup. Additionally, I added windows here when designing the floor itself.

I then imported the file to Fusion 360, but quickly realized that I would not be able to 3D print it as is.

I decided to model each part of it individually in Fusion, to a 1:60 scale. I chose this scale, because my printer is not very large, so I had to choose a size small enough that it could print, but big enough to show detail and the mechanisms for passive heating/cooling.

I started by modeling the base.

I then modeled out the first floor, making sure to model out the windows and the front door. This is so that the passive cooling/heating effect can be felt even in the model.

Note: Please open the last image for an explanation of the purpose of the indent.

I then modeled out the 2nd floor. I then covered the bottom to simulate the floor, and the top as well to simulate the second floor above it. Here I realized that an attic would be made, but as it did not contribute to the passive heating/cooling effect, I did not implement that into the design of the model.

Note: I decided against a front window in the model for the 2nd floor, as it does not provide any benefit to the purposes of the model.

I then went back to the first floor, and added 2 overhangs, one on the front for aesthetic reasons, and one in the back for the Trombe wall.

I then completed the roof for the 2nd floor of the house.

Diagram of a how a Barjeel keeps a house cool in hot climates.

Source: Environment Ecology

While I was designing the solar chimney in Fusion, I came across another technique used to passive cooling of houses in warmer areas.

A Barjeel is a traditional wind tower used in Gulf architecture to cool buildings naturally. It captures wind from any direction and channels it downward into the interior, while allowing hot air to escape. This creates a natural ventilation system that reduces indoor temperatures without electricity. Barjeels are an early form of sustainable design, common in old Emirati and Iranian homes, especially in hot desert climates.

Since I already was adding a solar chimney, and all it needed to make it into a Barjeel was a partition wall, I decided to implement this architecture into my design.

I then created the solar chimney, with holes and a partition wall to emulate a Barjeel. I made sure to keep it hollow, so that the cooling effect is noticeable even in the model.

With this, I completed the Fusion 360 models for both floors and the base of the house.

Having created the 3D models in Fusion 360, I put my models into the slicing software, and realized that for the purposes of a 3d model, it would be better to remove the walls for the 'rooms', as the model is not large enough that the rooms provide realism proportional to the extra filament use. (The base was kept the same)

Structure & Shell

3D-Printed Walls $18,000 – $30,000

Floor Slab/Base $2,500 – $4,000

Roof $3,000 – $4,500

Columns & Supports $800 – $1,200

Passive Heating/Cooling Systems

Trombe Wall $1,200 – $1,800

Solar Chimney/(modified) Barjeel Tower $800 – $1,200

Overhangs & Shading $500 – $1,000

High-Performance Windows $1,500 – $2,200

Ventilation Components $400 – $700

Energy Systems

Solar Panel Array $8,000 – $10,000

Battery Storage $4,000 – $6,500

Interior Buildout

Insulation & Interior Walls $2,000 – $3,000

Electrical Wiring $2,000 – $2,500

Plumbing $2,500 – $3,500

HVAC Backup System $1,200 – $2,000

Kitchen & Bath Fixtures $2,500 – $4,000

Flooring, Paint, Trim $2,000 – $3,000

Deployment & Services

Factory Assembly $3,000 – $4,500

Transport to Site $1,500 – $2,500

On-site Installation $2,000 – $3,000

Utility Hookups $2,500 – $4,000

Permits & Inspection $800 – $1,200

Total: $60,400 – $82,800

Sources: COBOD

Iconbuild

Solar Reviews

Eco Home

Home Advisor

US Department of Energy

Since my design is primarily based in green development, I wanted to quantify its renewable impact. Therefore, I decided to simulate a LEED certification.

For clarification: The LEED certification estimate is for the completed design, not for (only) the 3D model's design. It includes credits for items included in the cost breakdown, outline, and Revit file but not necessarily rendered in the .stl file/3D printed.

A LEED certification (Leadership in Energy and Environmental Design) is a globally recognized mark of sustainability for buildings. It signifies that a structure was designed and built using strategies aimed at improving energy efficiency (one of the primary goals of my design), reducing environmental impact (another key goal of my design), and promoting occupant health (integral to all houses, especially mine).

The current LEED version is Version 5.

Compared to Legacy v.4.1, v5 has:

1. Stronger focus on carbon – both operational and embodied.
2. Higher energy performance baseline – aligned with zero-carbon goals.
3. Performance-based credits – actual data matters more than design intent.
4. More emphasis on equity – social equity and community health are now integrated.
5. Resilience and climate adaptation – new requirements for future-proofing.
6. Simplified credit structure – fewer overlapping credits, clearer intent.
7. Material transparency + embodied carbon – deeper look at full lifecycle impact.

While my design has not been built in actuality, I was able to use the data that I had collected from the mean and median savings and climate impacts of implementing aforementioned passive heating/cooling methods (Steps 5-10, 42) in other countries and houses, to determine the impacts of my design.

After looking online, I learned that U.S. Green Building Council has a website in which one can simulate how whether a building qualifies for a LEED certification and which certification it qualifies for.

Sources: U.S. Green Building Council

General Services Administration

Image showing criteria for credits.

Credit: U.S. Green Building Council LEED Scorecard

The LEED certification v5 awards credits for meeting requirements in the following categories:

Location and Transportation

Credits for selecting sites that reduce the need for car travel, encourage walkability, and support access to public and low-emission transportation.

Sustainable Sites

Credits for protecting ecosystems, promoting biodiversity, managing rainwater, and reducing site-related environmental impacts.

Water Efficiency

Credits for minimizing water use indoors and outdoors, improving fixture performance, and implementing effective water reuse and management strategies.

Energy and Atmosphere

Credits for optimizing energy performance, using low-carbon and renewable energy sources, enhancing building commissioning, and reducing refrigerant impacts.

Materials and Resources

Credits for using products with lower embodied carbon, supporting a circular economy, minimizing construction waste, and promoting transparency and responsible sourcing.

Indoor Environmental Quality

Credits for ensuring healthy indoor air, thermal comfort, natural and high-quality lighting, and acoustic performance to enhance occupant well-being.

Integrative Process

Early-phase collaboration across disciplines to identify synergies among systems for water, energy, and site performance.

Innovation

Credits for strategies that go beyond existing LEED requirements, pilot credits, or exemplary performance.

Regional Priority

Credits for addressing local environmental, social, and public health challenges specific to the project’s location.

Sources: U.S. Green Building Council

Architectural Foundation

After filling out the U.S. Green Building Council interactive scorecard, I was able to project that my design would score a 87/110 with a ~5 credit margin of error (based on the fact that some aspects of my design are harder to find data supporting the concrete impacts of).

Even with this margin of error, my design scores (at minimum) an 82/110, which is still well withing the 80 credit minimum for a Platinum Certification, which is the highest LEED certification.

Materials

1. PLA Filament (~45g ± 2g)
2. Small piece of plastic ~1.5in² ± 0.25in² x 0-0.5cm(5mm)
3. Super Glue

Equipment

1. 3D printer- Creality K1 SE
2. Smartphone/Camera
3. USB Drive - to transfer GCODE (Not needed for cloud based printers)
4. Wire cutter

Software

1. Slicing Software - Orca slicer

Optional but suggested

1. Soft cloth, plastic, or paper (for blending of glue)

I then used Orca slicer (a free, open-source 3D printing slicer developed as a fork of Bambu Studio) to slice the models for 3D printing.

I then started started printing the three main components.

Note: When I was printing the 2nd floor, I incorrectly sliced the model, which resulted in longer than expected overhangs.

To give a sense of scale, I also printed a minifigure of a 5'9" person to 1:60.

To simulate the opening in the solar chimney (click on image in step 5 for clarification), I added a small indent into the base using the nozzle of the 3D printer.

To start, lay the 1st floor model diagonally across the 2nd floor model like so.

Apply beads of glue in a square pattern to the Trombe Wall like so, and attach the clear plastic. (Click on the image)

After completing the Trombe Wall, flip the 1st floor upside down and apply glue like so. Apply glue to all surfaces that will touch the base, and extra glue to bottoms of the columns.

After that, simply put the 1st floor on the base, making sure that the solar chimney does not hang off the side of the base. (Click on image 2 for clarification)

Take a piece of any material that is soft or paper, and blend the glue along the seam lines to ensure a clean connection.

Add a bead of glue to the place specified. (Click on image)

Add the figure to the place glue was added, and push down the figure to ensure a clean connection and push out any air bubbles.

To add the 2nd floor, add beads of glue to all upwards facing surfaces like so. Make sure extra glue is on the solar chimney and the dividing Barjeel wall.

Simply add the 2nd floor along the corresponding place on the 1st floor. Make sure to align the solar chimneys.

I would recommend using the chimney as a guide to orienting the 2nd floor on top of the 1st one.

After adding the 2nd floor, make sure to use the same material from step 59 to blend all the beads of glue from the connection of the 2nd floor.

With that, the 3D model is complete!

Born of a Community Need

The SunHaven Module represents to me more than just an engineering project. It is a solution born of my time with Youth in Government, and living in the American Southeast. It's a response to a real crisis affecting hundreds of thousands of families across Tennessee and Appalachia. Through months of research, design, and prototyping, this modular housing concept demonstrates that affordable, energy-efficient homes are the future of Tennessee.

Why This is Different

Unlike traditional housing solutions that treat energy efficiency as an expensive add-on, the SunHaven Module integrates passive heating and cooling into its very foundation. By combining modern techniques like Trombe walls and ancient techniques like Barjeels with modern 3D printing technology, I tried to create a home that works with the environment rather than against it.

The projected cost of $60,400-$82,800 makes this solution accessible to the families who need it most, while also ensuring its financially feasible for construction companies. The (projected) LEED Platinum certification potential proves to me that houses incorporating both that sustainability and affordability, not only are possible, but are the way forward.

Looking Ahead

In this house, I wanted to incorporate many systems and technologies that make this house as environmentally sustainable as possible, while retaining visual appeal, and space. Moving forwards with this project, I hope to be able to share my findings with builders and architects near me.

The Bigger Picture

Energy poverty isn't something that can be fixed with just one house. It requires a complete rethinking of our approach to housing. The SunHaven Module shows that with a future forward design and new technologies, we can create homes that do more than just provide shelter.

As a rising junior passionate about engineering solutions for pressing problems, I believe the future of housing in the Southeast lies in designs like this: practical, sustainable, and built with specific problems in mind.

I wanted to take a second to thank those that made this project possible.

Special Credits

1. Autodesk: Having a free student license available
2. The Energy and Resources Institute: Introduced me to renewable construction
3. YMCA Youth in Government: Introduced me to energy burden issues
4. My Family: For bearing with me while my 3D printer made lots of noise
5. Instructables: For providing this platform for me to learn from and contribute to

Research Credits

1. Think Tennessee: Energy insecurity research and statistics
2. Tennessee Housing Development Agency: Housing affordability data
3. Tennessee Department of Environment & Conservation: Environmental impact studies
4. American Council for an Energy-Efficient Economy (ACEEE): Energy burden analysis
5. U.S. Department of Energy (DOE): Energy assistance program data
6. Environmental and Energy Study Institute: Regional energy burden mapping
7. University of Calgary: Solar chimney and overhang diagrams
8. Australian Government YourHouse: Thermal mass principles
9. ResearchGate: Academic publications on passive heating/cooling
10. U.S. Green Building Council: LEED certification guidelines and scorecard
11. COBOD: 3D printing construction cost estimates
12. Iconbuild: Modular construction pricing
13. 3DRIFIC: 3D printing materials research
14. Solar Reviews: Solar panel system costs
15. Home Advisor: Construction cost benchmarking
16. US Census Bureau: Tennessee family size demographics
17. World Population Review: Population and housing statistics
18. General Services Administration: LEED certification processes