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If you are thinking about going off grid, then you’ll have a range of things to consider before committing. First, let’s talk about renewable energy and water supply. As you read, please keep in mind that this blog post will cover general advice, but it may also be important to seek out further information on the size of the systems you’re looking to put in place.
First, you must consider why you are going off grid. You may want to go off grid because your site doesn’t have access to power, or you may want to be more self-sufficient and flexible on where you place your tiny. Or perhaps you want to further reduce your environmental footprint by supplying your own electricity and water. No matter what the reason, there are some common themes to consider.
The best place to start when looking to supply your own energy is calculating how much you use. I usually suggest creating a list of the things you envisage using in the home that require energy, and put them into a table or document you can refer to later. Your energy demand will likely include lights, cooking appliances, ceiling fans, exhaust fans, a hot water system, charging points for electronic devices such as TVs, washing machines, dishwashers, water pumps, irons, hair dryers, heaters, and air conditioners. Once you’ve created the list, see if you can identify how much wattage each appliance might require per day or per week.
From there you will be able to identify some of the high energy items you may wish to consider alternatives for. For example, one of my clients was originally going to use ceramic cooktop hotplates in her tiny house, but due to their energy demands, decided to switch to gas hotplates instead. Similarly, you may want to consider gas powered hot water units over electricity powered ones, and ceiling fans over air conditioners. LED lights are also more efficient than fluorescent globes and tubes. These are all fantastic things to consider when mapping your power out. It’s also good to ask yourself if you need things like washing machines, or if there is a communal utility room instead, or if there is a friend’s machine you could use in exchange for dinner.
By calculating how long an appliance will be required for and the watts it uses, you will be able to estimate how many watts you will require per day. You will also need to consider how many days of energy storage you want your batteries to have in the event of cloudy weather or low wind. It’s this information that off grid suppliers will ask you for, so be prepared.
What are the roles of the inverters and batteries in all this?
The role of a solar inverter is to change the variable direct current from the solar rays to alternating currents, which are the currents used for appliances in the home. When choosing an inverter, make sure it is suitable for off grid application. The converted energy will then charge the batteries which will be used in the home. There are a number of factors that should be taken into account when choosing your off grid batteries, the main one being the two types of batteries you have to choose from.
Should I use lithium ion batteries or lead acid batteries in my tiny home?
Regarding price, weight, space, and efficiency there are a few key points to consider. Whilst lithium ion batteries are more expensive than lead acid batteries, about 80-100% is usable, compared to lead acid batteries where around 50-70% is available at any given moment. Lithium ion batteries are also considerably lighter than lead acid batteries for the same energy storage, which you will need to consider if you intend on moving your tiny house with batteries in tow. Lastly you need to consider if you will require several lead acid batteries compared to a similarly sized lithium ion battery, so be sure to consider the size of your storage areas.
Non-solar energy backup
There may be times when your battery storage hasn’t got enough in its reserves to provide your required energy, so you may wish to consider a diesel or petrol generator as a back-up as well. If you end up going for one, it’s a wise idea to locate it away from the house to reduce any annoyance from the generator noise and consider creating a special home for it. You can also link the solar system up to the generator so it turns on automatically when the renewable energy has been exhausted.
Where should I place my solar panels?
Placement of your panels is critical to generating energy. Many tiny houses have their solar panels located on the roof, but this means you will need to have your tiny house parked in an area where the panels can receive adequate solar radiation. Personally, I’m a fan of parking your tiny house in the shade to reduce summer heat, then placing the panels on a rack, pole or trailer setup, which allows them to be angled north. If you do place your solar panels on the roof of the tiny house, you will need to make sure that they are well secured to the panel frame and the roof to avoid them becoming a danger during transit. The weight of your panels also needs to be included in the overall weight of the tiny house if you are going to place them on the roof. As a guide, a 310 watt solar panel is around 17kg.
Let’s talk about water supply
Great, so now we’ve talked about renewable energy, let’s go over water supply considerations and in particular the generation of rainwater from the roof area. As you know, rainfall is influenced by the climate and the change in season. Some regions in Australia receive high rainfall over a few months in summer, and others receive winter rainfall, whilst others receive more variable rainfalls across the whole year. They say Australia is a land of droughts and flooding rains, and this is an important and distinct characteristic of our landscape to consider. Australia is also the driest inhabited continent in the world, with very high evaporation levels. That being said, when it does rain you want to have a rainwater tank on your roof large enough to capture all the rain you can. If you are in a tree-filled area, you may want to consider having a first flush diverter installed into your downpipe to reduce vegetative debris getting into your tank.
The roof area of most tiny houses is not large enough to capture all the water you will need across the whole year, but luckily you have a few options. The best thing to do is to create a water audit by calculating how much water you will require on a daily basis, and identify if there are any seasonal changes as well. For example, perhaps you have a veggie garden that needs more watering in summer. To reduce the demand of your potable water, consider using a composting toilet and efficient shower, installing economical hoses and taps, and maybe even raised wicking beds for your veggies.
If you install an oversized water tank to capture all the rainfall you can, you can then look at having the water supply topped up by a local water carter during periods of low rainfall. You could also increase the catchment of rainwater by collecting it from other roofs in close proximity, such as sheds and pergolas. You may even be able to connect to a water supply on the land. For example, perhaps the landholder irrigates crops. But sure the water quality is of a potable standard, as it might be coming from local dams or creeks. And lastly, whilst rainwater has been collected and used by households for centuries with varying degrees of filtration, it is important to consider filtering the water for drinking and cooking.
I trust this blog post has highlighted the key issues you need to plan for in the design of your off grid tiny house. If you have any other questions or would like to learn more about tiny house living, please drop us a line at firstname.lastname@example.org 🙂