ARBORA - Developing Affordable, Innovative, and Scalable Solutions to an Apartment.

How can a residence be economically accessible?

The solution is Arbora, an apartment building with a capacity of 236 residents across 89 units. The total cost of this project is over 8 million dollars and spans 25,275 square feet.

However, this can be offset with a profit of over 150 thousand a year and its innovative greenhouse temperature control system.

Hi, I am Atharv, a current high schooler from Charlotte, North Carolina, and in this project I will go over the creation of Arbora. Firstly, its name comes from arbor, a garden structure on which plants and vines can grow, inspiration you will see throughout this project.

Table of Contents

Research (1-4)

Step 1: Project Title & Introduction

Step 2: Site Selection & Charlotte Context

Step 3: Population and Demographics

Step 4: Climate and Environmental Data

Ideation (5-12)

Step 5: Project Goals and Vision

Step 6: Initial Revit File Setup

Step 7: Floor Layout and Room Types

Step 8: Greenhouse Window Design

Step 9: HVAC and Passive Cooling Logic

Step 10: Elevator and Access Planning

Step 11: Terrace and Roof Garden Setup

Step 12: Sun Path and Shadow Study

Design (13-24)

Step 13: Tree Placement and Landscape Integration

Step 14: Material Selection and Sustainability Features

Step 15: Lighting and Interior Renders

Step 16: Section Views and Cuts

Step 17: Solar Panel Layout and Power Study

Step 18: Apartment Interior Design

Step 19: Bathroom and Plumbing Layout

Step 20: Exterior Access and Streetscape

Step 21: Rendering Settings and Walkthrough Prep

Step 22: View Template Setup and Export Prep

Step 23: Sheet Layouts and Annotated Plans

Step 24: Final Compilation of Plans and Views

Walkthrough Development (25-26)

Step 25: Walkthrough

Step 26: Video Rendition

3D Model (27-28)

Step 27: Creating a Model

Step 28: Printing

Reflection (29-32)

Step 29: Calculating the Costs

Step 30: How Does It Stack Up?

Step 31: Is It Profitable?

Step 32: Conclusion

Here's what you need for this project:

Software programs

1. Revit
2. Fusion 360
3. 3D Printer Software (I used Flash Print)

Physical

1. 3D Printer
2. Pencil
3. Paper
4. Ruler (for alignment)

I chose to make my project in my hometown, Charlotte, North Carolina. Mecklenburg County, which most of proper Charlotte falls under, is the second-largest county in NC, behind Wake County, with a population of 1.164 million. The median income is $45,945 for a single earner and $83,765 for a household in Mecklenburg County. This presents a glaring issue as the median home price is $479,000 and the median apartment cost is $2,033 per month. This would mean a median single earner resident would be paying over 50% of their salary on just an apartment and over 35% of their salary on a 30-year house loan at 7% interest, assuming they already had the capital to finance it.

Charlotte is experiencing an increasing affordable housing crisis year over year. This is fueled by high population growth, constrained availability of housing, increasing real estate costs, and growing investor interest in buying and holding properties. Since the turn of the 21st century, Charlotte has emerged as one of the fastest growing cities in the United States (3rd), with the metro area receiving an additional 49,000 new residents between 2022 and 2023 alone. As indicated in a 2024 report by the Charlotte Planning Department, the city has a deficit (lack of) housing stock by a minimum of 11,500 units since 2012 and must now add more than 10,600 units per year to keep up with demand. The shortfall has created fierce competition for housing within the city, which has led to an accelerating of prices and making homeownership and even rental housing out of reach for many residents.

This can be seen with the price of housing in Charlotte increasing faster than the nation overall. The value of homes in Charlotte has grown about 72% from 2017 to 2024, and the United States increased by 41%. The median price of a home in Charlotte was $429,945 as of September 2024, as reported by Charlotte-Mecklenburg Housing Strategy. At these rates, a family would need to earn more than $51,116 annually in order to be able to afford the median priced home on a standard 30 year 7% loan designating 30% of their income towards the house which is what Charlottes government designates as affordable housing (30% or less of income spent on housing). This is a significant margin more than the 2020 median family income of a $48,670 based on U.S. Census data. Home renters have comparable issues. Renting median apartments in Charlotte is also $1,416 per month. Calculating this over each month would mean a cost of $16,992 which at a 30% expenditure using the government definition of low-cost housing, it would require $56,640.

Affordable homes for sale are also disappearing rapidly in Charlotte. Over 33% of homes that were sold in Charlotte metro for under $150,000 in 2014, but dropped to just 2% in 2024. As low as 19% of homes selling for under $300,000, according to the Charlotte-Mecklenburg Housing Trust Fund report. Naturally occurring affordable housing, or NOAH, has similarly become in short supply at just 8% to 15% of the available rentals that are affordable to those families who make less than 50% of the Area Median Income. This category of loss of affordability has served to increase displacement, especially in long-time Black and working-class communities. An increase in investor and corporate ownership has also distorted Charlotte's real estate market and reduced the amount of affordable housing.

In order to better understand the severity of Charlotte's emergency in affordable housing, it's also important to review information on supply constraints, economic needs, and demographic, all of which show the size and detail of the issue, which is rather complex; since Charlotte is such a diverse city ranging from open to rural areas with differing property values.

Housing Construction Trends and Permits

Charlotte issued an average of 9,000 residential building permits between 2018 and 2023, but only 12% were for multifamily units, which tend to be cheaper than single-family homes. Multifamily unit permits alone declined 8% last year from 2022 levels, which shows a slowing on the pipeline of affordable rentals. Construction of single-family housing added to the production of about 85% of new housing units, reflecting market preference and zoning allowing for lower-density development, according to the Charlotte Building and Planning Department, 2024.

Rising Housing Cost Burdens among Residents

As can be determined from the 2023 American Community Survey, more than 48% of Mecklenburg County residents who are renters pay more than 30% of their income toward housing, with 28% paying more than 50%. Of homeowners with home mortgages, 42% are burdened, paying more than the 30% affordability threshold. These numbers are up 7% points over the past five years, showing the growing issue. Households earning less than $35,000 annually bear the highest cost burden, with nearly 70% spending more than 30% of their income on housing expenses, which shows a large variation of income growth and housing expenses according to the U.S. Census Bureau in 2023.

Vacancy Rates and Rental Market Tightness

Charlotte's vacancy rate in rental property fell from 6.1% in 2018 to 3.4% in 2024, showing a sign of a tightening leasing market with fewer vacant units, according to National Multifamily Housing Council Data in a 2024 report. The lower vacancy rate drives rent up due to increased competition. These are more vacated and are also typically outer neighborhoods, less accessible to jobs and services. Highly sought-after central city neighborhoods have vacancy rates ranging below 2%, which indicates great demand.

Income Inequality and Housing Affordability

The Gini coefficient of Mecklenburg County, measuring income inequality, increased from 0.46 in 2015 to 0.52 in 2023, which indicates growing disparity. This rise tracks the rise in housing cost, which is an indicator that economic growth is being disproportionately shared with higher-income groups. The Mecklenburg Economic Development Report median income has lagged behind that of housing costs: median family income increased roughly 15% from 2015 through 2023, while median home values increased by nearly 60% in the same span.

Charlotte's affordability crisis for housing disproportionately impacts minority communities, such as Black and Hispanic residents. Black households in Mecklenburg County are nearly twice as likely as white households to be cost burdened, with over 55% of Black renters spending more than 30% of their income on housing. This is then compounded by racial income disparities—Black households' median income is around $43,000 compared to over $80,000 for whites—making homeownership and stable housing significantly less within reach. Furthermore, eviction records show that while Black residents make up around 33% of Charlotte's population, they are responsible for over 60% of eviction filings, showing the difference economically. This is even more stark in Charlotte, where black residents make up over 30% of the population, and Charlotte also has a 17% Latino population.

Impact of Institutional Investors on Housing Supply

In 2023, institutional investors bought an estimated 18% of houses in the metropolitan area of Charlotte, up from 10% in 2017. Institutional investors prefer to purchase single-family homes for short-term rental conversion, which removes supply from owner-occupiers. Homes bought by investors tend to sell at prices 8–12% above market value, pushing prices up across neighborhoods.

Commuting Patterns and Housing Location

The average one-way commute time for Charlotte residents increased from 26 minutes in 2015 to 31 minutes in 2024, which shows urban spread and housing cost burdens pushing people further away from work. People who live more than 20 miles out from the city center spend an average of $8,400 annually on transportation costs alone, when combined with housing costs, exceeds 45% of many moderate and low-income families household incomes.

Charlotte, has a humid subtropical climate with hot and humid summers and mild winters with occasional snowfall. The region receives enough precipitation throughout the year that supports dense vegetation and a long growing season. Located in a deciduous forest biome that is composed of broad-leaved trees like oaks, maples, and hickories that shed their leaves in fall. This biome supports a varied array of animal and plant species, and the seasonal cycle creates definite repetitive ecological patters.

This means that it allows for a variety of houses and environments with no specific structural major limitations.

3) Shown above is the Blue line, the main railway system of the Charlottes Area Transit System (CATS), it has possible building locations marked and the final build location identified starred.

I decided to make my first design prototype based on incorporating transportation directly into the build. I wanted to build a medium-sized apartment as this would allow the building to reach an economy of scale and have cheaper rooms for everyone inside, while also allowing for access to a full suite of amenities. However, it having a larger size than this would lead to the design being less modular and needing a bigger footprint, as well as a larger upfront cost.

My phase I idea was to have the building built around one side of the rail. I decided to make this built around a bridge so that there was cheap easy transportation using CATS. I found there was a lot of space that was wasted under bridges since many of these occur at key intersections of commerce, where low income housing could greatly benefit from the nearby amenities. I decided to put the amenities on the base floor and the rooms consisting of the three floors that are located above. I decided to also have an overhang to complement the L shape, so there would be cover as well as more space for rooms making it more like a train stop.

I didn't choose this idea specifically because it did not have a station on both sides meaning residents could only use it to go in one direction since CATS has few directions switches. I realized that creating a station above a bridge was one thing, but it wouldn't be feasible to add a station on the other side due to the thickness of the bridge and a lack of access. My initial train of thought was to have a ladder or way to reach the middle of the platform from the overhang above. This idea could not be used since the bridges have the tracks right next to each other, rather than spread out in some land areas. The functionality of this therefore couldn't be vitalized without a custom bridge, which would have greatly increased the cost of the building.

My phase II idea was to keep a station on each side with two main edifices extending from a base. I made the scale slightly larger with added height to the design as well as keeping the amenities on the first floor for easy access. This allowed there to be one station on each side going around both the bridge and the track and allowing for movement in both directions. I also chose to designate one whole floor where the station was at the finest point since there are no additional platforms on each side.

The main issues for this phase II idea were firstly the structural concerns—it would be weak with two overhangs and going around the entire bridge. Additionally, there was also a problem with the use case for this building as I was only able to identify a few locations on the entire blue line with a large enough bridge that was structurally sound and had nothing underneath it like an intersection for example, so this would only be applicable in a niche case scenario. The building also had several practical concerns. To change directions of stations you would have to go down three floors to the base floor and then go back up towards the other side which would be tedious and unnecessary. I also realized that there would be a permanent and lasting noise issue since CATS is active on the blue line 5:26 a.m. to 1:26 a.m on most days.

While reviewing stations on the blue line, I discovered many overhang bridges built to reach stations. I feel like using one of these, the build location I selected was near Sugar Creek Station, would allow the traditional benefits of building near the blue line and having access to it while avoiding the double-sided access to a railway and noise issues caused by the railway.

Having chose a format for a fixed building, I chose a three-story format, keeping amenities in the center arch from the two outer junctions. This would allow for communal space that would be lacking in the room, since I intended for them to be smaller in order to cut costs to meet affordable housing needs. I kept doubles together on one corridor, with singles on another and elevators 5' x 5' on both ends. For amenities, I chose to make the first floor a communal space and lobby. This area would also feature public bathrooms and a store for residents to shop with basic everyday essentials, like most groceries. This would be leased out to a separate private company to manage expenses and to keep costs down, as a larger supply network will help cut costs in this one small location. The second floor would have an open area with general entertainment options and an open floor plan, allowing events to be setup. The third floor of amenities will contain a gym as well as a laundromat. This will allow for the saving of gym costs also encouraging residents as it will be close by and slashing the costs of laundromats. According to the U.S. Energy Information Administration, the costs of having communal laundromats are less than half of that of individual units.

The building location I chose next to sugar maple station allowed for easy transport from many services. The above images display a one and a half mile radius, (2.41 km). This would generally be considered walking distance. In addition, the second image displays the rail stops of the blue line in red. These also further allow for ease of access, in addition to the area being well-connected with sidewalks for walking. The icons of each element are described below:

+ - Religious symbols for places of worship. There are many nearby the build location and of different sizes and sects.

Child icon - Schools, colleges, trade programs, and libraries. There are many schools nearby and often those of similar age groups are located together, like daycares and preschools, allowing for less transport for parents of similar aged children.

Heart icon - Gyms, places of wellness and recreational activities. There are many nearby with a variety of activies like golf, tennis, and arcades.

Tree - Parks, there are several nearby.

Spout - Gas stations, there are many near the build location and are essential in an affordable housing setup to save time and money driving to one.

Building - Restaurants and malls. Important for getting goods, several are nearby.

When I started coming up with a design, I knew the challenge wasn't just forcing bedrooms into a box, but preserving intimacy, functionality, and use within minimal square footage. I started with the 2-bedroom, 1-bathroom house, which I wanted to contain within a compact 20' by 25' footprint—exactly 500 square feet. It took me three attempts to achieve the version you see above, a particular issue was choosing dimensions for the house. I also chose to remove the laundry room which allowed me to reduce the footprint from 20'x 30' to 20' x 25' The goal was to accommodate a small family—ideally two to four people—without being cramped or wasteful.

The first thing I sketched out was the dining and living room, as that was the hub of most households. I gave it a 10' x 12' open dining space that doubles as a passageway to the rest of the house. I made sure there was space for a four-seat dining table with enough walking room. In order to avoid the area from feeling like it was closing in, I kept the living room adjacent to it at 10' x 9'. It is only sufficient space for a loveseat or a compact sofa, coffee table, and a 60" television. These two rooms share one open wall, which helps with natural light from front-facing windows and simplifies the path of HVAC since one PTAC unit can condition both rooms.

Next, I constructed the kitchen, which I placed against the interior's far-left wall. I employed the single-wall format—stove, counter, sink, and refrigerator in a line. It's cheaper to do that, and it leaves more floor space available for traffic. I made sure to maximize plumbing efficiency: the bathroom is in back of the kitchen wall, conserving on water and drainage lines.

The bathroom is tiny, its 10' by 4' but is a complete one: a standing shower, toilet, and small sink. By placing it in the rear of the plan, I was still able to make it private but also made it accessible from both bedrooms and the common area. Bathrooms can be one of the most expensive rooms per square foot, so efficiency was required. But I didn't want to make it so small that it will be cramped. I was able to do this by maximizing the open space and pushing the tub against three walls to keep it separate.

The bedrooms were the biggest design challenge. Bedroom 1, I designed in a 13' x 8' configuration, 104 square feet. That left me with room for a queen bed (5' x 6'8") and a little bit of walking space around the bed. I included a 3' x 4' closet and suggested that sliding closet doors would conserve precious clearance space that swinging doors would occupy. I also included a 6-foot window to allow light in for both of these rooms and make the space look bigger than it is. Bedroom 2 is narrower: 7' x 13', 91 sq ft, it still fits a queen-sized bed, a dresser, and a 4' x 3' closet. Both closets had sliding doors to allow for more space to be open. I added a shorter window to still let in light to this room, as I built the room with the mindset to keep the bedrooms at the end for the most outside exposure, since it's the room most people likely spend the most time in. This was even more evident in my design, which was set up so each room could feature a desk to double as a study.

Finally, I placed the PTAC heating and cooling unit on the front wall, close to the living/dining room, so that it could rapidly cool most of the house. Overall, I was mindful of space economy—making each square foot count, minimizing unoccupied hallways, and offering good natural light and air flow to avoid a feeling of claustrophobia, especially towards the bedrooms. The idea of the size being 20' x 25' was so that it would take up exactly as much space as two 10' x 25' single bedroom rooms, allowing the design of the building's floor plan wings to be entirely modular.

Then I addressed a smaller one: the 1-bedroom, 1-bath apartment for one or two adults. Much of this design was re-engineering the double to fit into an even smaller space. This space was going to have to fit into just 10' x 25', a total of 250 square feet, half of the double. From the beginning, I knew I'd have to go vertical with my space planning. This slender, elongated form lends itself to a linear flow, so I started at the forward end with an open kitchen and living area, giving it 10' x 12' of floor space combined. That left sufficient room for a minor seating area, table, and a kitchenette, all encompassed within one shared room—much like the double, the open plan was more flexible and allowed for more seemingly more space.

Then came the bathroom, centered in the unit. It's 7' x 7'—tiny, considering it is only 41sqft, but big enough for a standing shower, toilet, and sink. Plumbing stayed along the same wall as the kitchen to again be cost-effective. The bedroom is in the back, and I allotted it a 10' x 10' space, which was 80 sq ft. I put in a full sized bed (4' x 6.25'), space for a desk, so it could double as a study, and a 2' x 4' sliding closet. I included a 6-foot window to make it let in light. The unit is sleek in design, but it still offers privacy, real sleeping space, and working living space.

For my final layout, I would have 10 double units on each floor, each wing would extend 100 feet out, with 5 on each side. This would allow for 20–40 residents in double units. I would also have 20 single units of 1–2 people each, 10 on each row. Doing 40+20x2=80, which means my building would have a maximum capacity of 80 people on each floor, with three floors that would measure 240 people, with the exception of 4 less on the first floor so a maximum capiacity of 236, a significant amount considering it would take 66 times less space than the surrounding population area of more than a million square feet.

I also chose to include bike stands and a parking lot for easy access. It would be easy to reach other places nearby since there were many amenities in a walkable distance. A fundamental part I wanted to avoid was an underground parking lot, since it would cost significantly more especially for this relatively modest sized apartment.

I next got the idea of having net-zero carbon admissions. This would help the residence save money as in an all electric apartment almost 15% of fees go towards just paying for energy according to nc.gov. My idea to do this was twofold, one to include solar panels to generate energy for the residence. My idea was to cover about 60% of one wing, which would be square feet of the building in solar panels. The second idea I had for this was to limit heating and air conditioning, while doubling to get rid of the need for a humidifier. In charlotte, space heating can take up to 85% of an apartments' energy usage in the winter months.

I created a greenhouse inspired window system utilized as a passive climate-control layer for the apartment building.

The green house window system has a multi-layered facade hung in rows from the overhang of the roof that contains outside window space and consists of tempered translucent glass panes that are millimeters in thickness, these are also tempered to ensure safety of residents behind them. 1-inch vertical spaces are placed between them horizontally and vertically to divide each one of the 3-foot-wide panes, so that sunlight penetrates but heat and humidity do not enter or leave too quickly. Natural insulation reduces the building's dependency on heating and air conditioning equipment.

The overhang also is placed even farther to shield windows them from direct rain and hail to keep them more useful and reduce maintenance. Light continues to pass through the system, keeping well-lit interior spaces without unusual heat gain. Crevices between panes are furnished to provide for excess humidity to ventilate and free movement of fresh air, preventing molds and fungi from forming, which may be common in other building spaces with contained humidity and providing improved indoor air quality.

Also, an inverted fan system in the roof pulls fresher and colder air from the building roof downwards to lower floors, promoting vertical ventilation. The greenhouse system with rooftop Eastern Red Cedar trees providing humidity during the winter months for increased temperature, which I selected due to the fact that they are evergreen trees and have a light weight-to-size ratio, in a way that they are appropriate for planting on the rooftop. The trees work throughout the year, maintaining the regulation of moisture and the climate quality.

The system would be able to facilitate temperature control over all the main central rooms since they have a large surface area of the quarter circle as well as the single rooms. However, the double rooms are larger and feature a combined large by comparison kitchen and living unit. I added a PTAC unit linked up to a second AC unit where residents can control their temperature. This would allow for 76% of heating/air conditioning bills to be reduced in total (100% single & 50% double, there are more singles than doubles slightly).

I created a final sketch of what the body should look like. Each wing was 100x55 and the center was 55x55.

Now that the design is done, you can create a file to actually begin flooring out your model. I chose to use Revit from Autodesk, since it will allow me to create accurate architectural models of the building and realistically render and display them. If you are unfamiliar with these types of programs and just starting out programs, you can use Tinkercad, also by Autodesk, I used to help learn the fundamentals in school. Students can get one year free if you send proof of your enrollment.

Once you have downloaded Revit, you can choose a new model, and then load a default template. I chose to start with the smallest room, the single unit. Go to the architecture tab and insert a walled exterior to our dimensions, you can press shift for straight lines.

I drew out the lines as per was stated on the drawn floor plan, and then added doors and windows. I added a crescent window to lengthen the amount of bedroom space as well as provide a bigger sill. You can import from AutoCAD's large library by going to the insert tab and then Load Autodesk Family. I then replicated this to add furniture to the rest of the build, as well as the floors. I chose tile for the bathroom, and carpet for the rest.

I then worked on the double room. I made sure to include all the elements from before. Also, I rendered this room by going to the view tab, and then clicking render. There are many options, with a draft help you visualize the what you did where as the higher options like best and high can be use to presentably display the models.

I started by then filling in the main building with 20 small rooms, 10 on each row, and 9 total double rooms. I then added panes of glass and a front door while adding a back exit. The one less double room allowed for a store, this is where the extra supplies would be kept that were essential to residents. I also added a elevator to each side, this would be the main way to change floors. The left elevator goes from floors 1-3 and the right goes from 1-4 (in this image).

I created the main lobby with reception a waiting area with couches and seating. I also kept two unisex bathrooms for use of guests. I also filled in the store with different spacing for varying items and groceries.

I then used a section selector to make each part more visible by using a section box and highlighting downward allowing better sight inside the rooms with high walls.

The next step is to make floors range up. I did this by grouping a empty version of the floor and then copy pasting it to a select row. This allowed me to copy it to the the other levels. I had four levels, the roof was included since I had to build over it later too to access the terace. I also changed the roof to raise the middle and have a slightly large main room. It was extended by about a foot. I also added extra bricks to highlight windows in the design. These planes will be past the regular windows and will not have the second layer of greenhouse windows over them, allowing for a clearer look to the outside.

I started by making a ring around where I wanted the greenhouse windows around the arch, since I couldn't make curved windows with straight glass. I then put the glass on the tips of these ends and use the cutter with spacing tool to separate them. I made the windows 1 foot long and three feet wide. I kept a one-inch separation between them vertically and horizontally to allow some light and moisture to pass through. The windows are also slightly translucent, being made out of safer storm resistant tempered glass. I then traced the sides of all the windows, scaled the surrounding glass by grouping each layer and duplicating it.

I then removed the measurements I used to make it and rendered the final result so far.

The issue the rendering before was the greenhouse windows now covered all parts of the exits as well as the visibly extruded windows, meaning you count actually get into the building or see with an unobstructed view out of it. I ungrouped each of the rows and deleted the surrounding panes on both sides.

I started work on this by making four walls and connecting it to the right elevator system from before. I also changed the roof using focus lines and put a double door for access. I then used the railing (handrail) around the right side, this would be the terrace for residents.

I started work on this section by making solar panels out of sets of six and grouping them, allowing for ease of access for maintance. I also provided the two AC units, that would be indiviusally working. One would funnel regular air conditioning to the PTAC units in the double rooms. Where the other was for use for the greenhouse ventilation from the tree spaces on top.

I then worked on the parking lot adding in some trees, parking spots (including handicaps close to the entrance), and vechiles. I also added bike racks since there is good sidewalk and accomidations for biking and walking in the area. There are also many workplaces in the area so residents can commute with only bikes as well.

I started by putting in the evergreen trees for the second AC module closest to it. As determined from my climate anaylsis, evergreens can grow well in Charlotte, which currently has many variations of them. I chose evergreens, specficially the Eastern Red Cedar due to its continuation of photosynethsis and moisture regulation even during winter, as well as its low weight to size ratio.

I then cut a hole in the roof using the editor tool for it and replacedd it with a fixed piece of glass to give more natural light into the gym room of the building.

I finsished off by expanding the visible area and adding more trees and foliage, as well as making the accurate roads surrounding the actual building based off Google Maps. I also added benches for functional use around the front and side wings.

Full Download

I created two walkthroughs by placing the points throughout the model on each floor. I used the edit walkthrough to change the

The graphic quality is pretty low, I rendered this with a setting of 640x360p on the setting: realistic 24fps, since my computer wasn't very powerful and each frame is a different render it took over four hours for these two walkthroughs to complete.

The first task was to strip the current model to its bare bones and include only the parts that were important. I went through about 5 renditions, to make the correct sizing. In this, I emptied out all the interiors except for one room, a double I cut out for viewing, to add stability.

I then exported it from Revit and used Fusion 360, by AutoCAD. Fusion allowed me to scale the model correctly and then export it into a format for 3d printing. For my model, I used a scale of 1:500. This means one millimeter of my 3d printed model would be equivalent to 500mm on the real thing, or half a meter.

Exporting this to FlashPrint, I then sent the instructions to the 3d printer. The printer will also create a series of struts around it to help support the overall structure and can be taken off after.

After the printing was completed, I peeled off the extra struts that were used for support, and was overall pleased with the product.

The project's cost estimate, a low-income sustainable apartment building in Charlotte, NC, has 89 apartment units—29 larger 500 sq ft apartments with 4 occupants and 60 smaller 250 sq ft apartments with 2 occupants—spread across three stories with a total floor area of 25,275 sq ft. With energy efficiency and affordability being primary considerations in the design, the building has two elevators, a greenhouse facade, rooftop trees, and a 60x60 ft solar array. These features significantly influenced both the long-term operating and construction costs.

Hard construction costs accounted for the biggest share of the budget, with approximately $5.92 million. This sum includes the foundation building structure, HVAC systems designed for passive cooling, greenhouse window incorporation, rooftop tree structure, fire safety equipment, and parking facilities for bicycles and automobiles. Solar panels added expense but were counterbalanced by never again paying for electricity. Soft costs—architecture, engineering, legal fees, and permits—added another $1.18 million. Site work such as utility connections, grading, landscaping, and trash infrastructure had been pegged at around $426,000. It included a 7.5% contingency fund for unforeseen expenses.

Adding all these categories, the gross development cost amounted to around $8.07 million. However, due to the solar installation that generates an estimated 87,000 kWh of electricity annually, the project would achieve over $450,000 in power savings over 30 years. When this energy offset is included, the net-effective cost of the building drops to around $7.62 million. This works out to a cost of around $136,000 per unit, or $44,800 per resident, far below the average cost range of low-income housing developments in Charlotte that incorporate sustainable technologies.

In all categories Arbora is significantly cheaper than recent developments of low cost housing in Charlotte, NC. This was impressive considering it also offers less costs in the future due to its energy saving capabilities. One factor leading to its lower costs is the cheaper cost of land in the build location.

The estimates are based off of mecklenburghousingdata.com

With a total layout of 29 double apartments (500 square feet each) and 60 single apartments (250 square feet each), the ARBORA project maintains its total square feet of 25,275 while optimizing for maximum occupancy and affordability. With a rent of $400/month for double apartments and $200/month for single apartments, the building earns a total of $23,600 per month, or $283,200 annually. As the construction relies solely on sunlight and does not have in-unit independent appliances like washers and dryers, the operating cost is kept minimal. Assuming that a typical 35% of annual revenue goes into maintenance, insurance, water, waste, workers, and reserves, the operating expenses are approximately $99,120 annually, leaving a net annual profit of $184,080.

The net overall profit over a 30-year timeframe would be $5.52 million. The cost per resident remains extremely low at $44,800, taking into account the energy self-sufficiency gained by virtue of the 60×60-foot solar panel array and passive greenhouse design. The financial structure of the project not only sustains itself in the long term, but also in the short term robust, and resilient to vacancy or subsidy fluctuations without relying on high rents. This makes ARBORA not only profitable, but also stable, sustainable, and replicable in other areas of Charlotte or other urban settings.

The Arbora project realizes significant cost savings for low-income tenants, mostly in the way of reduced rent and lower utility bills. At $200 per single unit and $400 per double unit in monthly rents, which is significantly less than Charlotte's median one-bedroom rate of around $1,200, tenants save around $800 to $1,000 in rent per month compared to market rates. Over the course of a year, that equates to $9,600 to $12,000 in savings that can be applied to essential expenses such as food, healthcare, transportation, and education. To boot, the building's integrated 60x60-foot panel array of solar panels and energy-efficient greenhouse design greatly reduce electricity consumption, cutting average utility bills by up to 50% or more. Since utilities tend to comprise 10-15% of a household's total housing expenses, this decrease also alleviates residents' financial strain. Overall, Arbora's combined savings on rent and utilities can enhance disposable income by thousands each year, dramatically enhancing residents' financial well-being and lifestyle.

Through this project, my first time using Revit and Fusion, I have learned a great deal about the intricacy and significance of developing affordable housing that is sustainable and profitable. It was a fun task to create the build. The project opened my eyes to how the newest design technologies—greenhouse windows, solar panels, and optimized landscaping—not only reduce long-term operating costs but also enhance the health of inhabitants. I also gained an appreciation for how much it matters to consider local climate, community needs, and economic situations to make a project like this viable and reproducible. Overall, this experience taught me more about the possibilities and challenges of creating housing solutions that are affordable, socially responsible, and environmentally friendly.