What you are making
In this project you sketch a floor plan: a drawing of the home seen from above, showing its outline, rooms and windows.
You will set four things:
- The size and shape of a simple rectangle.
- Its orientation: which way the long side faces.
- How much window area goes on each side.
- Your climate zone, from your homestead brief.
The tool then gives a rough heat-loss estimate and saves the plan to My plan. It is a planning sketch, not a design for construction.
Simple shapes work best
A simple rectangle is the cheapest shape to build, heat and keep dry.
- Every corner, jog and bump adds wall area, framing, roof complexity and places for air and water to leak.
- A compact shape has less outside surface for the floor area inside, so it loses less heat.
- A rectangle a bit longer than it is wide, with the long side facing south, gives good winter sun.
Text description
Three floor outlines seen from above, each with 576 sq ft (about 54 m²) of floor, with south at the bottom. A 24 by 24 ft square has 96 ft (29 m) of outside wall, a 24 ft (7 m) south wall and 4 corners. A 16 by 36 ft rectangle with its long side south has 104 ft (32 m) of outside wall, a 36 ft (11 m) south wall and 4 corners. An L-shape has 112 ft (34 m) of outside wall, 24 ft of south-facing wall in two parts, and 6 corners. South walls are drawn with a heavy line.
Orientation and rooms
Orientation is the direction the building faces. In the US, turn the long side toward true south if the site allows (lesson 10).
Then place rooms by how you use them:
- Living and kitchen on the south, where winter sun lands in the day.
- Bedrooms, storage, entry and bathroom on the north, where they act as a buffer.
- Kitchen and bathroom near each other, so water and drain lines stay short. Plumbers call this a wet wall or wet core.
- An entry with two doors, or a small enclosed porch, keeps cold air out in cold zones.
Text description
An example floor plan seen from above, north at the top, 32 by 18 ft (about 9.8 by 5.5 m), with a scale bar. It is a planning sketch, not for construction. Along the north side, from west to east: a bedroom with a window for light and escape, a bathroom, a storage closet, and an entry with two doors, an outer door and an inner door, to keep cold air out. Along the south side is one open room: a living area to the west and a kitchen to the east. Part of the kitchen sits right below the bathroom, so they share one wet wall and the water and drain lines stay short. Most of the windows are on the south wall, where low winter sun comes in. The east wall has one window for morning light, the west wall one small window, and the north wall two small windows.
Windows on each side
Window area is the biggest choice in this project. Windows lose heat faster than walls, but south glass can gain it back on sunny days.
- South: most of the glass, with an overhang for summer.
- East: some, for morning light.
- West: limited, because of hot summer afternoons.
- North: small, for light and cross-breezes.
Every bedroom also needs a window large enough to escape through in a fire. The code sets the size. Your designer will check it.
How the heat-loss estimate works
Heat loss is how fast the house loses heat to the outside, in BTU per hour or watts. The tool estimates it from:
- The area of walls, roof, floor and windows.
- How well each one is insulated, based on your climate zone.
- The temperature difference between inside and a typical cold winter night.
- A rough allowance for air leakage.
It then subtracts a rough share of solar gain through south windows on sunny days.
Sketch your plan
Try a few versions. Turn the long side south, then east, and watch the estimate. Move window area from west to south. Shrink the footprint by 10 percent. Save the version you like best.
What to take to a builder
Print or export your plan from My plan, along with your homestead brief. Bring these questions:
- Does this footprint fit the site, the setbacks and the foundation type that suits the soil?
- Can the roof span the width simply, or does it need interior bearing walls or posts?
- Do the window sizes and positions work with the framing and the code?
- What insulation levels and air-tightness target do you suggest for my climate zone?
- What will a proper heat-loss calculation show, and what heater size does it suggest?
Check
Two plans have the same floor area in zone 6A. Plan A is a rectangle with its long side south and most glass on the south. Plan B is an L-shape with large west windows. Which will usually lose less heat over a winter?
Summary
- A simple rectangle is cheapest to build and heat.
- Turn the long side toward true south when the site allows.
- Put living spaces south, buffers north, and keep kitchen and bath close.
- Put most glass on the south. Limit west glass.
- The heat-loss estimate compares options. A professional sizes the real heating.
- Take your plan and brief to a builder or designer, with the questions above.
You have finished Track 2. Track 3 moves outside, to water.
Go deeper: surface-to-volume ratio
Heat leaves a house through its outside surface. Heat is needed for the volume of space inside. So the ratio of surface to volume matters. Small homes have more surface for each square foot of floor than big homes, which is one reason a tiny house can still feel cold. A compact shape, a simple roof and no unheated bump-outs keep that ratio low. Two stories over a small footprint can also help, if stairs suit the people in your brief.