There are plenty of lists out there that give you the basics on living in an off-grid THOW, but what about the real issues? Here is some practical advice based on first-hand experience of industry professionals living tiny.
1. Not all Land is Created Equally
Look for elevated positions requiring the minimum for land clearing and leveling. Look up your locations almanac of weather history to understand the seasonal averages. This can help calculate how much water storage you may require as well as knowing the wind direction to best catch the summer breeze and block the winter winds. If you are near a water course, be aware of the flood levels and make sure your house site is above them.
If you are in the southern hemisphere, know where North is, as the sun always orients this direction. Try to place your house so the longest side is facing north. This is also the direction solar panels should face for maximum efficiency. East and West facing sides are the most exposed to the sun and hardest to shade. While being close to trees can be beautiful, stay a good distance out of tree canopies as this can cause a long list of issues including leaves in the gutter and easy access to your house for critters as well as weather and bushfire concerns. Know that a trees root system is almost identical to its branches, so any footings under a tree canopy can be compromised by the roots.
2. Make sure it's certifiable
In almost every circumstance, sooner or later your THOW will need to be permanent. If you ever contemplate selling your THOW, it will hold much more value if you have the certificates for the home being built to Australian construction standards. Permanent dwellings require a building certifier and/or a structural engineer to provide forms stating your building has been constructed to the required standards. Without these forms, your THOW cannot be considered a permanent building. Trying to obtain these certificates after your house is built is very difficult, time consuming, and expensive even if your builder says it was built as per NCC(National Construction Code) standards.
3. Make it permanent
While there are many advantages to your THOW being considered a caravan, in the long run, in most cases it is better for it to be a permanent structure. Being mobile gets your THOW into many places a normal dwelling cannot. It is also much easier to finance if it is considered a caravan, and you can find a ‘parking spot’ for it with minimal to no red tape, however once you are in that ‘perfect’ spot, most Councils have strict rules over how long a ‘caravan’ can stay in one location.
If you had your THOW constructed with all its required certificates(see number 2), all it takes is proper foundations and your THOW can be considered a permanent building. A screw pier footing system can be installed for your THOW without any concrete and minimal if any machinery. These can be unscrewed and taken with you if you ever decide to move. This opens up many ways to comply with the various Council regulations that THOW classed as a caravan cannot.
4. Useable outdoor space
When considering going tiny, most people are looking for a lifestyle based on the outdoors with the tiny house as more of a ‘base station’ from which life revolves, but doesn’t necessarily happen within. Let’s face it, they’re tiny, and regardless of the weather, you will need outdoor area to spread out on and enjoy your amazing location.
For this to be a great lifestyle, a covered deck that can be enclosed with screens and can also capture rainwater can easily double the livable area of a THOW. Most areas of Australia can have days of heavy rain, or weeks of searing sun. Let’s not forget the bugs. Mozzies love coming out around sunset, the best time for an outdoor meal, and spiders and flying insects love the light. Without an enclosed deck of some kind, you will be stuck inside looking out.
5. You need more POWER!
Despite the romantic videos of THOW owners happily living on two solar panels, any relatively normal lifestyle will require a lot more than that. Coupled with the fact that batteries are by far the most expensive part of your off grid PV system (about $1,000 per Kw), any realistic power system needs the panels to charge the batteries when the sun is out.
Most people cannot afford the amount of battery storage they would like when getting set up, so look for industry standard inverter/battery management systems (like Victron) that have the capability of using a variety of different battery types so your system can grow as battery tech evolves. Panels are the cheapest part of your system and provide the most government rebates, so max out your panels – even if it requires a separate structure – because 2 or 3 days of constant rain will drain your batteries to a critical level.
Also, allow for a backup petrol generator that can connect to your system’s inverter and charge the batteries when the sun is not cooperating. Know your power system as this can be your lifeblood off grid.
6. Water
Living off rainwater has so many health benefits and is critical to living off-grid. With climate change making more drought and flood cycles, it's crucial to maximise our water catchment to fill the tanks when it pours so we can outlast the next drought. If you looked up the weather history almanac, it is possible to estimate how much water storage is necessary and how much roof area will be required to fill the tanks sufficiently through the year in your location. One thing is for sure, your THOW roof will not be enough to fill a big enough tank for even basic water use in the majority of Australian (and worldwide) locations.
Adding a covered deck area that captures rainwater can add enough catchment area to get through the dry spells. Don’t forget to add a first-flush system and check the gutters regularly so your rainwater is as clean as possible before it hits the tank.
It’s easy to calculate how much water your roof will collect. 1 square metre of roof covered in 1mm of water equals 1 litre of water. If your THOW roof is 2.5m wide x 8m long, that's 20 square metres. 1mm of rain = 20 litres of water. If you have a 10,000L tank, it will take 500mm of rain to fill it without any usage being considered. To put it into perspective, that’s Melbourne's entire rainfall in one year.
7. Wastewater and sewerage
While a composting toilet is almost a rite of passage for THOW living, it adds a weekly/monthly chore to your list and will most likely be well at the bottom of that list. In addition to dealing with your own sh*t, your greywater also has to be taken care of, in addition to kitchen grease.
While there are a few Council approved systems available to deal with this waste, a standard sewerage treatment system takes care of all of this waste just like a normal house, and does it in a more environmentally sensitive way. If you know you'll be in one spot long-term and aren't interested in adding those less than pleasant chores to your list of things to do, investigate sewerage treatment systems.
8. Stormwater
As part of your land considerations, the most common worst-case scenario is torrential rain. The east coast of Australia is renowned for extreme rain events which means part of your site work needs to address stormwater runoff.
If the site is on a slope, then make sure the pad you have graded for your house has around a 1 to 100 slope towards the low point of the site. Then create channels around the edges of the graded area so that heavy runoff goes around your house and away downhill. By doing this, when its raining for days, you can sit and watch from the comfort of your home rather than battling floodwaters of your own making.
9. Shade
Due to the width restrictions of the caravan/THOW classification, most THOW designs have no eaves and no window shades. It's unrealistic to think this creates a comfortable indoor environment in an Australian summer. Plan on adding removable window shades of some sort to at least the north facing windows with deep shade coverings over east and west wall openings. This will be the difference between chilling in comfort or sweltering on a hot summer’s day.
10. Insulate!
Whether hot or cold, insulation is the cheapest way to maintain indoor temperatures in a tiny house. The vast majority of heat is gained and lost through the roof, so this is where you need maximum insulation. Look at structural insulated roof panels (SIPs) for maximum insulation and minimum thickness.
11. Enclose your floor
Most THOW standard trailers leave the floor structure exposed. Request this to be enclosed with galvanized sheet metal. This makes it much more difficult for critters to sneak into your THOW, adds the ability to insulate the floor easily, and prevents any pipes or wires under the floor from damage if you take it on the road. This is money well spent.
12. Storage
Most people will be downsizing when going tiny. Rent a storage unit so that you can gradually get rid of stuff and can make sure things are not needed before shedding them.