Energy-Efficient Eco House Model – Smart, Green, and Affordable

Hi! Im Tanner Christensen a 9th grader from Elk Ridge, Utah. Ive always loved creating things. There’s something really rewarding about turning a design into something real. I taught myself how to use fusion 360 and have loved using it. This project has helped me learn a ton about using this software and real world thinking. This design was inspired by the fact that around 60% of U.S. electricity comes from carbon emitting sources like coal and natural gas. That is 25% of the nation's greenhouse gas emissions. This design uses solar power and natural cooling to help protect the planet, showing that you don’t have to be high-income to make a difference.

Software:

1. Fusion 360

Devices for designing and documenting:

1. Computer
2. Camera

Materials for model:

1. OSB board
2. Paint
3. Nails
4. Glue
5. Cardboard
6. Joint compound (for stucco)

Tools for model:

1. Circular saw
2. Jigsaw
3. Finish nailer
4. Clamps
5. Pencil
6. Square
7. Level

Around 60% of U.S. electricity comes from carbon-emitting sources like coal and natural gas — That is 25% of the nation's greenhouse gas emissions. During my research for this house, I found that cost is one of the biggest reasons people don’t go solar. I designed this home to make sustainability affordable for everyone. The total cost, including solar and natural cooling features for a 1,000 sq ft house, is actually lower than average. Also federal tax credits can reduce the solar cost by 30%, and the ongoing electricity savings make it even more accessible.

For the preferred location I chose Washington County, Utah near St George. A several acre property would work best for this because you could have several of these houses on the land to have the most difference. I chose this area because southern Utah gets more than 300 days of sunshine per year making it perfect for solar systems. There is also a lot of affordable flat land which helps reduce excavation and construction costs.

The number one consumer of energy in the average U.S. home is the heating and cooling system, also known as HVAC, which uses about 46% of the home’s energy. That’s why I added a closable vent system. The vent system takes just a small cool breeze and pulls air through the bottom of the house, pushing the hot air to the top and out a second vent. This reduces the temperature in this specific climate by 8 to 12 degrees Fahrenheit and can reduce AC use by up to 50%.

Solar panels were a no brainer. The average 1,000 sq ft home uses 1,000 kWh per month on the high end. This specific array on the house is a 9 kW system, which given the location and the A-frame design with a good roof angle, can produce 1,200 to 1,400 kWh per month. Using the high end estimate of 1,000 kWh per month, and accounting for natural cooling savings, the house would only use around 750 kWh per month. This means the homeowner could sell the excess power back to the city, saving even more money and helping the city become more sustainable.

For solar angle and strength to hold the solar I decided to make an A-Frame house. The next steps will take you through the process of building it.

I learned A lot about building houses during this project. For example, the horizontal studs on this frame are called firebreaks. The studs are placed about 16 inches on center, adjusting if the length of the house doesn't match that exactly, or to make room for the front door.

For insulation, I chose fiberglass batting because it is the most affordable and widely available, while still being very effective for insulating. Another option would be Rockwool, it's almost twice as expensive as the former, but it's fire-resistant, mold and water resistant, provides some soundproofing, and offers higher sustainability.

Purpose: Forms the structure of the walls and roof

I used osb texture to show the actual sheathing houses use.

Purpose: Protects from moisture, allows breathability

I put kind of a Tyvek texture to represent house wrap.

Purpose: So you can see outside😂

Natural lighting helps save electricity, and opening windows reduces the need for AC if theres a breeze. Theres two windows on the short side of the house that would be facing south to help heating in the winter.

Purpose: Protects the home and reflects heat

Metal roofing is durable and perfect for hot climates like southern Utah.

Purpose: Durable, breathable, weather-resistant wall covering

I added stucco to make it look more realistic and decorative.

Purpose: Clean, renewable electricity

I chose 400w panels that are usually 40 x 66in so I placed them in that size.

Purpose: Natural cooling to reduce AC use

This is based on stack ventilation, cool air comes in low, hot air rises and exits up high. And gives a nice cross breeze through the home.

I added a second floor for use as a sleeping area most likely.

I decided to take a different approach than most. I built a physical model of my home design, about 3 × 2 × 2ft , using real building materials. I spent around 7 hours building and finishing it, and made sure to include all the key exterior details like solar panels, vents, and a realistic stucco finish.

I built it at about a 1:9.5 scale using real construction materials to show how the full size version could actually be built.

I left out studs, drywall, and insulation since including them at this scale would’ve been unnecessarily difficult.

I went with 3/8in OSB for the house because the model’s pretty small, and anything thicker would just be too bulky. At first, I was going to use actual roofing metal for the roof, but it would have been a pain to work with, and I realized the solar panels wouldn’t work because its not flat. For the solar, I represented them by cutting out pieces of leftover OSB, scaled them to match the house, and painted them black to look like real panels.

This is a full time-lapse showing the entire process. From cutting and assembling the walls, to painting the exterior, applying the roof, and finishing with a realistic stucco texture. It shows every step of the build from start to finish.

What is the Federal Solar Tax Credit (ITC)?

The federal solar tax credit is a clean energy credit that you can claim on your federal returns. This tax credit is not valued at a set dollar amount; rather, it’s a percentage of what you spend to install a residential solar photovoltaic (PV) system. The tax credit is currently set at 30% of your total solar panel system installation cost.

Source: Eco Watch

Estimated Cost Breakdown

Framing (lumber, fasteners) $15,000

OSB sheathing $3,000

Roofing $6,000

Windows & Doors $5,000

Insulation (fiberglass) $3,500

Exterior finish (stucco/siding) $4,000

Interior drywall & finishes $6,000

Flooring $4,500

Electrical system $5,000

Plumbing $4,000

HVAC & Vent System $5,000

Paint & misc materials $2,000

Labor $35,000

9kW Solar System $18,000

Estimated Grand Total: $116,000

Total After 30% Federal Tax Credit on Solar

1. 30% of $18,000 = $5,400 credit

Adjusted Grand Total: $110,600

The average cost of a 1000Sq ft home:

Near St George the median price per square foot is approximately $275/sq ft

For a 1000Sq foot home ~$275,000 (Estimated)

Source: Rocket Washington County report June 2025

Building this project has helped me learn in so many different ways. First I learned way more about fusion 360 then I did before, second I learned so much about real world construction, third I learned so much about energy and how to conserve it, finally I had the opportunity to adapt accordingly when I faced problems. I had tons of fun designing the model and seeing it come to life.

I also learned you don’t have to have a new house to conserve energy. Even something simple like opening a couple windows to let a cross breeze through your house to naturally cool it, or even just turning off lights during the day!

This design shows that sustainability doesn’t have to be expensive or complicated. It uses solar energy, natural cooling, and smart design to reduce carbon emissions and lower costs, making sustainable living more accessible to more people.

Thanks for this awesome opportunity! This project taught me a ton and helped me grow as a designer and builder.