Tiny House Off Grid Solar: Help for Beginners in 2022
– By Rhys Coffin, Off Grid Solar Designer
If you are looking for help with tiny house off grid solar in New Zealand – especially if you have a project that needs power in the next six to 12 months – then this article could save you a lot of time and money. Here’s why:
There’s a lot of misinformation around.
Most of the time it’s well intentioned, but it usually comes from suppliers, online shops or sparkies who most of the time have limited design or engineering credentials, and little actual experience with helping customers through multiple winters in a row.
While our purpose is not to poo-poo the competitors, we do speak from authority having manufactured and installed many hundreds of systems over the past decade in every corner of the country.
There is no doubt that living off the grid can be a positive life-changing decision. But you need to go into it with your eyes open.
Over the years, we’ve become accustomed to ‘rescuing’ families from tiny house off grid solar systems that have been installed by others. A lot of the times these families have been sold a solution that wasn’t fit-for-purpose.
Sometimes they have had no-one to turn to when their system shuts down at 3:00am in the middle of June – and they live out in the wops.
That’s why if you are open to hearing the truth when it comes to tiny house off grid solar, this just may be the best thing you’ll read today.
And while you may not become our customer (we’re not a good fit for everyone), we hope you get some good practical value out of this article.
Before you scroll down, if you haven’t already seen it, we recommend you check out our wildly popular Off Grid Solar for Dummies article. There may be some overlap with this off grid tiny house solar article, but our ‘Dummies’ article covers the whole off grid solar subject in a more general way.
Could we be a good fit for you? We design and manufacture tiny house off grid solar systems that deliver the best long term value over 15, 20 or even 25 years. We help people who like to deal with the experts, who use quality components and the latest technology. If peace-of-mind is important and you want a solution based on your actual power needs, location and lifestyle, then get in touch. There is no charge for our design service.
We don’t judge anyone when it comes to budget or the ability to afford off grid solar power.
But the fact is, some people who are downsizing to tiny house living are doing it because it’s a cheaper way to live. They are constrained by their budget.
They need it to be low-priced (and fair enough).
Because we have designed hundreds of tiny house off grid solar systems over the years, we know the subject of budget is very important. That’s because low priced off grid solar systems are not usually designed to last.
In our experience, low priced systems will need replacement sooner rather than later. It may be after the first winter, or it could be after five years.
If you only have X dollars in the bank for solar, you may have no option but to install a system because it’s cheap. That’s cool with us.
But we also want you to know that there are consequences of buying the lowest price ‘deal’. While it looks like excellent short term value, the long term value proposition is horrible.
It’s a false economy.
Heres the exception: If your tiny home off grid system is for a bach or weekend place that’s only going to see summer use at holidays and weekends, then there’s a good case for buying a cheap and cheerful system.
But if your tiny home is full time and you plan to be living there for 10, 15 or 20 years, and if you need reliability, then going cheap and cheerful could be a recipe for disaster.
Just because the footprint of your tiny house is small (it may be 30m2 or less), this won’t necessarily translate into a smaller (or cheaper) system.
That’s because the sizing of your system should be calculated on your daily load and your location.
As an example, we have designed tiny home systems as low as $18,950 inc GST and as high as $80,000 inc GST.
Apart from your normal house appliances, if your tiny house off grid system is also powering a swimming pool, a spa pool, underfloor heating, full electric cooking, electric hot water, a clothes dryer, and you are living in Southland, then it’s easy to see how the size (and price) can be high.
It’s all relative.
Don’t panic. Most systems will be waaay lower than that, but it’s an example of ‘house size doesn’t matter’.
Your daily load
Your ‘load’ is the amount of total power you will consume over 24 hrs in winter (expressed as kWh). As well as this, your location helps us to calculate the sunshine hours for your region based on computer modelling, and therefore the number of solar panels you might need.
Everyone is different.
Your size (and price) will change depending on how you handle your hot water, heating and cooking. If you need your off grid system to cover any or all of these items, then that could increase the size (and price) by half, twice or even three times, compared to a system that has alternative sources of energy, such as gas or solid fuel.
We’ll be the first to recommend getting the power connected, if going off the grid doesn’t make financial sense.
If you already know that the cost of getting the power connected to your tiny house site is more than say, $15,000 or physically impossible due to the geology, topography or the distances involved, you might want to skip this section.
If you want to live off the grid as a lifestyle choice, even if power’s close by and available, you too may want to skip this section.
But if you are not sure about the viability and are looking to compare grid tied vs off grid, then read on because this is what you need to consider:
What’s the total price to go off grid? There will be other costs to consider over and above your Power Station unit, panels and components. These include having an approved auto-start generator (yes you probably need one), and the installation costs. Get in touch to arrange a short phone meeting, and we’ll give you a price estimate over the phone.
Get a quote to get connected. What’s the cost to get your local lines company to get your site connected? This will depend on distances, whether power poles are needed, whether a transformer is needed, and other factors. Once you know the price we can talk about viability because every situation is different. Here’s the link to find the lines company in your region.
Dead money. Putting any amount of money into getting your lines company to connect your tiny house is dead money. It will be the next owners who benefit – not you.
Long term or short term? It may be hard to know, but how long do you intend to live in your tiny home? If it’s your ‘forever home’ then it should stack up financially. While you’ll probably never lose money on a quality off grid system if you sell up in five years, the overall value increases for every year in the house.
The load evaluation can be a bit daunting for most people, which is why it’s part of our free design service.
We are more than happy to check your calculations. We don’t recommend you spend money until we check the numbers and do some computer modelling.
Apart from question of how you intend to run your hot water, cooking and heating, there’s a lot that we take into account to get it right.
Be aware of builders, online sellers or electricians who aren’t able to help you with a line-by-line load evaluation and provide a rationale for their numbers. Most of the time they leave that up to you.
Your location influences your system size because of the sunshine hours for your region.
It’s important that your system is sized for the month of June, when sunshine hours are at their lowest. No-one wants to have a system shut down or the generator to run every day in winter.
Getting the correct loads for each appliance you have. We can advise you on efficient options if needed. You don’t need to do hours of research.
Understanding your lifestyle patterns which help us to develop your ‘power use profile’. This could be very important to know especially if you are a shift-worker, if there are young children or teenagers and whether you are home during the day in winter. There’s lot more but this is just a taste.
Will your power needs decrease, stay stable or increase over time? Our systems are modular and expandable
Giving you all of your options when it comes to cooking, hot water and heating. These could include the pros and cons of hot water heat pumps, thermodynamic water heating, wetbacks, infra red heaters, heat pumps and more. You are not the first to do this, and we can shrink your learning curve.
The two important areas to consider are the solar panel array location and the physical housing of your Power Station system (you can watch the video here to see what our self-contained system looks like).
Let’s discuss the solar panels first.
As you know from reading above, the power your system provides is the result of your daily load and the number of solar panels needed. Panel numbers are also calculated by the official sunshine hours for your region.
Because of the limitation with roof space for many tiny homes, you may have to consider mounting panels on a ground array.
Standard high-efficiency panels today are usually sized at over 1m x 1.7m. This means that for eight panels, your roof would need to be nine metres wide. Remember there will be a gap in between each module, and we need to account for this.
So, if your roof is only six metres wide, you may have no alternative but to build a ground array platform.
We can provide plans for timber ground arrays that can be low-cost to build. There are also metal arrays that we can supply.
Many modern tiny houses that have a monopitched roof will be sloping the ‘wrong’ way (usually to the south) when placed on the site. If that’s true for you, you’ll need special tilt-legs, to achieve at least 20 degrees above the horizon, depending on where in New Zealand you live. This can add slightly to the cost.
Rows of solar panels on a roof that are tilted up towards the north, can cause shading from the front row to those panels behind. This is another factor we can help you calculate.
We are manufacturers, not installers. Your state-of-the-art tiny house off grid solar system is built to stringent NZ Regulations and designed to be compliant with safety regulations.
While we do have approved installers in most parts of the country, it’s important to ensure your system is installed in a compliant manner.
The Regulations that apply to your installation are AS/NZS 5139:2019. This Joint Australian/New Zealand Standard™ was prepared by Joint Technical Committee EL-042, Renewable Energy Power Supply Systems and Equipment.
The Regulations state that Lithium batteries must be installed in a separate cabinet (that’s how they come out of our factory), in a structure that is separate from the main dwelling.
This means storage underneath the dwelling or in an external cupboard may not be compliant.
In the past, tiny house builders may even have built a recessed cupboard with external access. These may be non-compliant under the Regulations.
So what’s the alternative? It’s a small garden shed.
The options for the shed location are under a ground array (it can be hidden away if designed right), or nearby to the tiny house itself.
Getting your tiny house off grid solar system signed off by an electrical inspector so that your Code of Compliance is valid is important not just because of safety, but because failure to comply may void your insurance and warranties in the unlikely event of a problem down the track.
If you have questions, please talk to us about your design and options.
If you are ready for a quick chat, please get in touch. We are happy to answer your questions, review your site/building plans, help you with load sizing or if you are ready, provide a quote and report.
A reminder that our other resources on this site include: