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“Tiny house” by aehdeschaine is licensed under CC BY-ND 2.0
Tiny Home Design Deliverable Requirements
These minimum elements must be addressed as part of your design and should be represented in your final design report. There will probably be more to consider. The client has left the choices of occupant profile, location, and mobility up to you, so settle on those early to define your group’s broad objectives.
Occupant Profile
The constraints on a tiny home mean designs must be well tailored to the user group. Comparisons require a baseline to determine changes in dollar cost, social, and environmental impact. Your report must include a typical user profile like this one:
Sue owns and lives in a 900 square foot downtown Kingston condo with her teenage daughter and their dog. Sue’s MS sometimes requires mobility aids like canes or a walker and stairs can be difficult. They travel by gasoline car to multiple destinations within urban Kingston with total distance of about 15000 km/year. Purchase price for the condo was \$400K. Condo fees are \$500/month, which includes water and sewer. The condo has electric resistance baseboard heating, electric hot water, and no air conditioning. Electricity costs average \$120/month. (All in 2018 dollars.)
Your occupant profile will be different, e.g. two university students as roommates, a small family, etc. and your choices of target will drive many design details, particularly budget limitations.
Location
Determine a potential location in or near Kingston where your tiny home design will meet regulatory requirements, including zoning rules. Start your design with the assumption of a full sky view for solar and don’t forget the cost of the land purchase or rental and possible changes in commuting distance in your analysis. Generic locations could include:
- Hypothetical future Kingston where zoning rules have changed. Full sky view in the west campus area. City water, sewer, electric, cable, phone connections all available. Street access.
- Rural location on Highway 2, 20 km outside Kingston. Full sky view. Limited access to untreated well water, septic system, cable, phone, max 30A at 115V electrical available (split circuit could be used as 15A at 230V).
- Rural location 50 km north of Kingston. Full sky view. 500m from road — no services.
Mobility of the Tiny Home
In addition to considering the personal mobility of your occupants, will your tiny home be:
- Mobile like a house trailer, with wheels? Width will be limited by traffic laws and weight by your choice of tow vehicle.
- Movable by lifting onto a truck with a crane like a mobile home? Width still limited by traffic laws, but could be “wide load”.
- Permanently installed on a foundation? Dimensions and weight flexible. Doesn’t need to resist transportation loads.
Floor-plan and Building Envelope
Provide a layout for your tiny home that includes less than 300 square feet internal floor area. Meet building code and other standards for dimensions of passages, etc. to meet your accessibility goals. Test your plans for real traffic situations with mockups by moving furniture in a classroom to match your dimensions and then moving through it and documenting the results. Be sure to consider two people passing each other, and the challenges of changing sheets on the beds.
Custom millwork (cabinets, etc.) is expensive, but your design may not have room for ordinary kitchen cabinets. IKEA Hackers provides inspiration for adapting mass marketed IKEA solutions to your own needs. Consider using that approach to get designs that fit and provide reasonable value and use the IKEA pricing in your cost estimates.
Thermal design of the building envelope is complex. You could simply specify an overall R Value for your tiny home’s walls and windows and make a reasonable estimate of construction costs on a $/square foot basis, taking into account the small size and energy efficiency level you are looking for. Do not attempt detailed design and costing of the building envelope beyond selecting your windows.
Energy Systems
Off-grid or Net-zero almost certainly means solar and batteries for electricity. Specify details of your solar system, selecting from available products. Specify all significant electric loads such as appliances, lighting, HVAC, car charging, etc. and select from available products.
Be clear about your required performance criteria, particularly for heating, both when the home is occupied and when it is empty. (At a minimum, it should be safe from freezing when nobody is home.)
Water / Sewer
Detail your design / costs for providing adequate clean water supply and sewage / grey water disposal at your chosen site.
Backup Systems
Your tiny home will probably need backup systems for heat and electricity that will seldom be used. Size and select appropriate systems from existing products.
Operating Simulations
Simulate the energy production, storage and consumption over a sequence of multiple days. Evaluate operating decision making required, e.g. need to run propane backup heating or gasoline generator to meet operations.
The ideal simulation will follow historical data through some segment of a Typical Meteorological Year on a suitable time step like 15 minutes or an hour. At a minimum you should look at the performance differences between
- A clear, cold, winter day
- An average winter day
- A cold, gloomy winter day with 90% of the solar energy lost to the clouds
Cost Estimates and Comparisons
Prepare dollar cost estimates comparing the tiny home solution to the baseline solution from the occupant profile. Your solution will have to be attractive to the potential occupant in comparison to their other options.
Compare environmental impact, particularly carbon emissions.
Compare social impact associated with changes in location, community, space for guests, etc.
Be sure to include all aspects linked to home choice, e.g. changes in commute time / costs / carbon.
Regulatory Compliance
All engineered systems must comply with applicable regulations. Even when regulations have not kept pace with technology and good engineering practice, your projects must still comply. For this project we are assuming that property standards bylaws and building code requirements have been relaxed to permit more compact construction, however all other systems must be in compliance.
A “normal” dwelling will include a grid connection for electricity, city water and sewage connections to plumbing, or a well and traditional septic system where city services are not available. You must either incorporate all of these utility connections, or demonstrate that local regulations do not require them. If you are including non-traditional systems, you must demonstrate compliance with locally applicable regulations. In particular be sure to consider:
- Grid tie compliance for any connections between your locally generated electrical power and the public power grid.
- Interior installation details for toilets other than traditional water flush units.
- Drainage of liquid waste, including either grey water or urine to the property through systems other than traditional septic beds.
- Storage and disposal of solid waste, either on or off the property.
Media Attributions
- Tiny House