Energy Efficient Cardboard Model Home

I designed a cardboard model passive solar home that demonstrates some design concepts that can help to maximize the energy efficiency of a home.

I designed my house with the most amount of south facing roof surface as possible, to maximize my solar exposure and to most effectively and efficiently make use of the energy in sunlight. I designed a roof with an overhang that minimized the amount of Southern sunlight entering the house and allowed for the proper amount of Northern light. Additionally I made use of a clear story to maximize the stack effect and add ventilation. Beyond that my house is very simple and has a lot of potential for customization as well as the addition of more energy efficient features.

1. Required tools and materials
2. Tools
3. Soldering iron
4. Hot glue gun
5. Ruler
6. T-Square
7. Razor knife or precision cutting tool
8. Cutting mat
9. Heat gun
10. Materials
11. 6 ¼ x 6 ¾ solar panels (20v)
12. Portable battery
13. 16 Gauge wire
14. Solder
15. Heat shrink
16. Led lights
17. Small Fan
18. Splicer block
19. Electrical Switches
20. House Construction
21. Required pieces
22. 15x11 (2)
23. 6x11 (2)
24. 2x11 (2)
25. 14x11 (2)
26. 15x14 (2)
27. 10x11 (4)
28. 13 ¼ x 10 (2)
29. 10 x 3 ¼ (2)
30. 7x1 ½ (2)
31. 2x2 (8) (Cut diagonally for 16 - 2x2 triangular braces)

There are many design aspects that make a good solar home, some fairly obvious like roof orientation and grade, however many people overlook ideas such as thermal solar chimneys and thermal mass for heat retention. Do some research on these design principals and pick a few that you feel like demonstrating, or if you have the time, pick all of them and build the ultimate passive solar home.

If you're feeling brave and you can visualize your house design really well I guess you could jump right into building it but I like to do a little bit of planning so I don't end up re-doing work. Sometimes the saying "measure twice and cut once" is true.

The easiest way for me to design my house is to sketch simple 3D concept sketches and then once I have the general idea more refined I like to scale it by drawing each side two dimensionally and labelling every single measurement. Before I actually start building I like to cut some rough reference pieces to make sure my house is scaled correctly.

The first step in building something is gathering and prepping your materials. I do this by making a checklist of every single piece of cardboard I will need and then working down the list, measuring, marking, and cutting the pieces very methodically.

When it comes to assembly I like to start at the bottom and then opposite sides, carefully measuring and making sure everything is square and plumb as I go.

With my specific house style I built one wing and then used it as a reference to trim the more intricate shapes.

When the house finally looks like a house do some poke and wiggle tests to see where the weak spots are and add braces as needed.

Now that you want to power your house you need to do a little bit of planning or you're either going to catch your cardboard house on fire or do a bunch of extra work for no reason.

Draw a circuit map starting with your power sources. If your power source supplies too much power for your loads you may need a resistor so you do not damage your accessories. Next plan how you will control your accessories, you can't have them on 24/7 so how will you switch them? Will they all be on one switch, will they all be switched separately, or will each room have its own switch? Personally I switched the output from my power sources with a three way switch so I had three options; 1) All off, 2) Solar Power, 3) Battery Power. Additionally I switched my two fans separately but put all of my lights in parallel and on the same switch, much like string lights.

Start the circuit building/wiring by first establishing where all of your negative leads will end up. When working with smaller scale projects like this I like to have a common grounding point that all of my negative leads will end up at. This means that with any accessory, as long as the positive lead is getting power the circuit will be complete, and this means that it will be harder to accidentally mis-wire something and short one of the power supplies. Next measure and cut all of your wire lengths, too short of a wire is obviously and issue, and way too long of a wire can get in the way or cause confusion. Next deal with the wire ends, twist, wire nut or fasten a connector to the ends depending on what you will be using the wire for. The next step is connecting a switch to either the positive or negative end of a device, I prefer the positive side but either side will do as a switch is essentially just breaking the circuit. After your switches are in place, wire all of your negatives to your loads and supplies, and then have them meet in a common location. Remember to pay attention to polarity when doing this. After all of your negatives are "grounded," connect the positive side of your loads to the positive leads from your supplies, this can be done with wire nuts, solder, crimp connectors, or whatever you prefer. Again just remember to pay attention to polarity and additionally make sure your circuit isn't shorting itself out. Once all of your connections seem to be in place, test and test again and double check that everything is working as it should. If there are any connections that aren't totally reliable just re-do them.

Finally, your system should be working and you are going to implement your electrical system into your house. I used a simple board for demonstration purposes, however accessory and switch placement is up to you. The only things I will recommend are, test as you go so you don't have to make any repairs while the system is in the house, put your power sources somewhere safe and easily accessible, and put your switches in a convenient location in case something goes haywire.