14.4 KW solar, 40.96 kWh backup, 2 solark 15k inverters, off grid family home, doable or delusional?

[Themillpondhouse]

We live in South Louisiana, but are planning to build a house in North Louisiana on owned property, if we choose to sell our current house. There is a lot of development coming up where we are at, and we don’t like it. We received a great offer on our house from a developer because we have highway facing property that is right off of an interstate exit. The offer is roughly 4x what we paid for our house so it’s appealing. It is enough that by the end of it we would be able to build mortgage free, with a new build, with money left over, if we utilize the land we already own.



However due to the current housing market, it is hard to find a place we like, with enough acreage, in our budget, in our state, without having to remodel many things, with a shop for our business, without having to mortgage some of it.



Pretty much, housing market horrendous, rate horrendous, it makes more sense to build.



The alternative of not selling and us staying will result in us staring at a truck stop being slapped up across the street on the newly rezoned land. and behind us will eventually be converted from farm land to industrial. So our land up north is looking pretty good right now from that standpoint.



Here’s the big kicker after all my copious amounts of research; It would have to be entirely off grid which is not normally done in this area. Zoning is outside city limit, so off grid is permitted, no restrictions. Called a couple of local Solar companies and they either aren’t in service anymore, or they only do grid tied. Im having trouble measuring the scope of this.



There is a lot of resistance against renewable energy in our state thanks to Jindal (governor a few years back vehemently against Solar) along with the state thriving pretty heavily on the oil and gas industry. It is not embraced.



We had the electrical engineer come out and assess our property a couple of weeks ago. Cost to run electrical to property would be upwards of $60,000, not including cost to clear the lane for electrical or removal of canopy. Also would have to gain easements from surrounding timber company land owners, which will probably not happen, or will come with hefty price in addition to.





Comparable acreage in this area is upwards of $100k and not easy to plan on it being available 6 months later (due to a long due diligence period with developer) so It is worth it for us to pay for an ample Solar setup on the property we already have. I think it would be less costly to do that, than to buy a plot to build on that already has utilities.



We are a five person family; me, my husband, 3 kids. Not looking to do the whole tiny house thing. Not getting EV vehicles in the future.



So here’s the scope of what we are planning to build

Modern farmhouse 3 bedroom 2 bath main floor
2570 sq ft heated/cooled living space

Also,
416 sq ft bonus living area upstairs over the garage with a bathroom (will not be used much)

2x4 framing, Spray insulation. Orient house with long sides North and South. Front Door will be facing south.



Location is in North west Louisiana area, Approx 25 acres is ours. Flanked by additional 66 acres that is also family owned (uncle) on one side, and paper mill timber land on the other. It is on a private gated road so very private and secluded, yet about 10-15 minutes to nearest town. Outside of city limits.



Water will have to be well. Well company said between 80-280 feet is the norm for the area. I’m not sure what that translates to pump size, but can source that if needed. I know the water pumps can be taxing on the load.



Septic- aerobic w/ sprinkler.



HVAC- we think that the MrCool universal heat pump split system up flow/horizontal 4 to 5 ton 18 SEER (ducted) would be best option for us. I will say I am having trouble trying to discern how much of a load this puts on a system. I know it would be better than the traditional central AC setup. I also know that mini splits are less taxing than this, but they are ugly as sin and this seems like the happy medium.



Other things that would use power( and not all at once but regular/usual usage:

The usual light situation for a house that size (led bulbs, being mindful to have no Edison or funky stuff)

TV (multiple, kids)

Starlink internet

Garage doors (2)

Ceiling fans (at least 4)

Cove security system

Laptop, electronics, cell phones charging

Kids game devices

Range hood with vent

New Dishwasher (energystar)

New Full size refrigerator without fancy screens etc (energystar)

Electric dryer (energy star)

Electric washer (energystar, the current one we have is top loading)

Garbage disposal

Microwave

Oven part of gas range is electric



Note on dryer: will be switching to gas when this one dies. It’s about 5 years old, Samsung.



We may go new with washer and dryer to get ones that are better suited for our solar setup.



Occasionally I use an air fryer, blender, bread machine, rice cooker, toaster, standing mixer, etc. rarely use the coffee pot because we like French press but we have one of those too. Of course not all at once.



Estimating we need at least a Propane tank 500 gal



Propane appliances:

Tankless gas hot water heater

36 inch ILVE gas range (electric convection oven)

Vented gas fireplace insert



Also Generac dual fuel 18kw w/ standby switch whole home generator, I think this would be ample size for the house/solar backup.



Other details; our current usage is extremely high due to living in a 1937 home with basically no insulation and it is drafty. South Louisiana has also been quite a bit hotter than the north this year. Also older appliance usage, older air conditioning units, along with a shop that we run our business out of on current property(lots of power tool usage) makes estimating off of our current usage extremely innacurate.



If we build, then our business would be located separately from residence and in the town.



A comparable usage would be my inlaw’s house in the same area as we are building. Highest month usage is August, with 39.4 KWh a day/ 1144 kWh a month. Their house is about 2300 sq ft and they have older appliances, at least a 3 ton AC unit that is older as well, not very rationing with lights or televisions, and they use space heaters like crazy in the winter. I believe that August is the most taxing due to having to cool so much for it also is our hottest month.



So about what we think we need:



I found this on shop Solar kits website.



14.4kW Solar Power System - 2 x Sol-Ark 15K's + [38-40.9kWh Lithium Battery Bank] + 36 x 400W Solar Panels | Complete Solar Power System | [HDK-MAX]



We are looking at this, with the 2 x Sol-Ark 15K inverter option and the 8 x EG4-LL - 40.96kWh / Server Rack Battery - 5-10 Year Warranty option.



This is a complete kit that seems to fit within the parameters of our needs but I am not sure if it will be hefty enough. There’s just not enough data I have found out there of people doing something like this on this scale truly off grid.



It’s at 57kWh a day which is oversized for the current usage estimate I am going off of.



Also 40kWh of backup means roughly a day of backup on the heaviest days which sounds a little spooky. I’m hoping that the generator will cover this a bit when needed. In-laws are about 15 min away so if a bad week happens then we have a place to go to keep the system at minimum.



It is easily expandable to up to 44 additional 400w panels, and 8 x power walls (batteries?), along with an additional inverter if needed to increase output.



So if this system struggles, we have ways to easily expand.



Solar array will not be roof mounted, because I don’t want hundreds of holes in my new roof. Also I read about heat from the roof impacting the panels and that just sounded bad because it gets hot here.



We will have a cleared area with ground mount. We have land to work with. Looking at a seasonal tilt vs the fixed option.



Altogether this would run about $50k. We aren’t batting an eye at that because it’s less than what it would cost for entergy to run a line if that is even an option (easement issue). That’s the kit with the options we want, and a seasonal tilt mount. I looked for one with what seemed to be the best that’s out there and plenty of warranty.



We plan for Solar to be in a separate shed with a small mini split, or in the room in the garage (but cooled). Leaning towards shed, because room in garage is less than 4 ft wide and I would rather not have batteries in my house.



It would be a DIY install which also makes me a little nervous. It comes with schematics and everything you need to get the system up and running. The best alternative I have found is a man from Lafayette with a local solar business that said I am looking at about $120k upwards for a truly off grid system that can keep up, with him traveling and installing it. A few others I have called only due grid tie.



My husband has a few years of electrical experience as a journeyman, but not with solar. He is familiar with industrial installations as well and very mechanical savvy. He feels pretty confident in the install. He also thinks I am crazy and overthinking this. I think for new build construction permitting in our area, a licensed electrician may have to make the final connections or inspect the system (our builder is willing to help us figure this out).

 

[Themillpondhouse]

If I did it right, PVwatts says 20,049 kWh a year with the lowest months being November/February with a monthly range of 1200-1350 kWh



In north west Louisiana, the summers are hot and oppressive; the winters are short, cold, and wet; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 38°F to 93°F and is rarely below 25°F or above 99°F.

We get about 214 days of sun, 114 of those are partly sunny, and 100 of full sun.


State sunlight rank 18/50

Average Annual Sunlight Hours: 2600 hours

Clear Days: 101 days per year

Summer Peak Sun Hours: 5.71 hours per day

Winter Peak Sun Hours: 3.63 hours per day

Average Peak Sun Hours 4.92 hours per day
Not many seem to be doing this path. I’m sure most of it is that there is usually no need to do so here. We would have funding to do all of this and have some left over, I just want to be sure I have the true scope of things. We are not power hogs but we are also not necessarily a prepper family or wanting to do this for simplistic or rustic living. We like our modern comforts and also given the area, keeping cool in the hot days. I would be able to balance and manage loads to not run everything at once.

Also during most week days, we would be gone from the house until the evening due to work/school. Our shop will be located at inlaw’s house and the kids would come home to there until we would go home for the evening. So the usage load during this time would be minimal, other than putting appliances on timers to get day loads done while we are out.

Am I missing anything? Am I out of touch? What else am I not thinking of?

If you made it through this essay, I commend you. Thanks in advance for any advice.

 

[1201]

If you're going to be in a well, look for a solution that has a low surge. Like the grundfos pumps.

I wouldn't get Mr cool units. Get a regular mini split and a $120 vacuum pump and gauge kit. That way you can shorten the lines as needed

 

[Mattb4]

We live in South Louisiana, but are planning to build a house in North Louisiana on owned property, if we choose to sell our current house. There is a lot of development coming up where we are at, and we don’t like it. We received a great offer on our house from a developer because we have highway facing property that is right off of an interstate exit. The offer is roughly 4x what we paid for our house so it’s appealing. It is enough that by the end of it we would be able to build mortgage free, with a new build, with money left over, if we utilize the land we already own.



However due to the current housing market, it is hard to find a place we like, with enough acreage, in our budget, in our state, without having to remodel many things, with a shop for our business, without having to mortgage some of it.



Pretty much, housing market horrendous, rate horrendous, it makes more sense to build.

The first major issue with selling a place you live in and moving to undeveloped land is having a place to live while developing that land. There is no present services there. This adds a great deal of difficulty with simple things getting accomplished. It is not just no electricity but there are other amenities that do not exist. Having bought and developed homes twice now over my life on remote parcels of property I can say that it is not for the faint of heart and it may be too much for a family with children to do.

It also is going to cost more than you can imagine if you have never developed land from raw to homestead.

 

[Themillpondhouse]

The first major issue with selling a place you live in and moving to undeveloped land is having a place to live while developing that land. There is no present services there. This adds a great deal of difficulty with simple things getting accomplished. It is not just no electricity but there are other amenities that do not exist. Having bought and developed homes twice now over my life on remote parcels of property I can say that it is not for the faint of heart and it may be too much for a family with children to do.

It also is going to cost more than you can imagine if you have never developed land from raw to homestead.

I’ve gotten quotes for every utility we would need, quotes for building house with accounting fora cushion over budget of about 25%, along with quotes for gravel drive, house pad, dirt work, clearing of land, you name it, I’ve gotten it. It all fits well within our funding with a good amount of room for error and unexpected costs.

This is more of a case of owned landlocked property than a true off grid rural location. It is our hunting property that we would like to make into a homesite. Civilization is about 10 minutes away.

The only thing that is somewhat iffy is the solar aspect. Is this going to be enough power or should I account for more?

We also have a solid place to live while building that is within an 15 minute drive, and we know our builder pretty well so I feel like his estimate is very solid.

 

[Quattrohead]

Your potential new home sounds very similar to the one I am building in Florida, except I went with ICF for hurricane resistance as well as insulation.
You might be OK with 1 inverter but should probably plan on 2 paired together, the 14kw of panels sounds fine but I would bump the battery up to 100kwh.
Any fully variable speed HVAC will be good, I choose an ACIQ 3 ton system, hybrid HWT.
BTW putting the panels on the roof is a good idea, they will shade the roof and actually cool themselves with natural convection under them.
Mounting systems from Ironridge are 100% water proof and I am sure self build you will be more careful with this.

 

[Themillpondhouse]

Your potential new home sounds very similar to the one I am building in Florida, except I went with ICF for hurricane resistance as well as insulation.
You might be OK with 1 inverter but should probably plan on 2 paired together, the 14kw of panels sounds fine but I would bump the battery up to 100kwh.
Any fully variable speed HVAC will be good, I choose an ACIQ 3 ton system, hybrid HWT.

The kit comes with 2 inverters with ability to easily add one more. I was also thinking more on battery but I also know you need enough panels to keep additional battery tanked.

 

[pvgirl]

4-5 tons is probably over sized for around 3000 sqft, a load calculation such manual J or similar(such as the free: https://www.loadcalc.net ) will determine what the actual load for your home. For most home layouts a ducted system is going to be the best option, either a traditional air handler, or a ceiling concealed slim duct unit. A propane Direct-Vent Wall Furnace that doesn't require electricity is a common last resort heat source for off grid homes.

 

[BentleyJ]

Since you have obviously already put a great deal of thought into the project. My first recommendation would be to simply take the list of appliances noted above and put those on a spreadsheet and assign some electrical consumption estimates. At the very least 2 columns, Peak kW demand and daily KWh energy needs.

Having Propane is a big plus for sure and the dual fuel generator is nice in case there are Propane shortages and you need extra electricity to heat water and cook. (assuming the other gen fuel is gasoline)

I recently did a quickie electrical audit of an all electric rental house I own in the desert region of So. Cal. Was a bit surprised to find the potential electrical peak demand was 34kW. On course not all the appliances would be on at the same time. On the other hand, our primary residence with Nat Gas appliances has never exceeded 6kW even with summer A/C running.

Based on your post, seems like your new residence is somewhere in the middle. I believe the kit you propose would be a comfortable choice to begin with.
1) Absolutely agree with the decision for ground mount. This way you are not limited on solar PV due to roof space. Would recommend oversizing the conduit between the PV array and the inverter location so additional panels and parallel wiring can be added easily. Ideally you pull in the extra wire at the beginning.
2) Consider building a well pump/pressure tank house/shed large enough for the generator, inverter and batteries. Generator in a separate section with ventilation.

 

[superchachi]

My 2 cents.

prioritize air sealing the house. Put more budget toward air sealing and insulation...the kind that you can spray.

We live in central texas...similar in many ways...just not as much humidity as y'all get. Manual J calcs are nice, but they are not worth much unless you have a tight house in my experience. There is a reason most HVAC contractors still like using their rules of thumb...because the south gets really, really hot and humid. And like most energy efficiency ratings, they like to use averages. That is great, but it doesn't help you at the margin...when it is really hot and really cold. Don't get me wrong, I just did a full manual J calc for our house remodel...but, it is only as good as the input. The beauty of the ACIQ hybrid ducted deals is that you get the benefit of the variable speed stuff (so you can "oversize" and cool your house on the hottest days) and also be able to heat your house with electricity when the temps outside are below 34 degrees (which we see every February here). Our current heat pump won't run in near freezing temps...toaster oven heat anyone?

Based on real data from our house (using Emporia energy monitors), our A/C accounted for 75% of our electricity this summer. We have a propane on-demand hot water unit, but have electric everything else. A/C, oven/range, dryer are the big users. The Goulds well pumps (lift and pressure pumps) are not big users for us...and we are pumping 350' to the surface). Our dryer and induction range (newer units E-star) use 5-7.5kw when they are going.

Normally we are 50-60kwh/day in the non-ridiculous weather months and 120-130kwh/day when it is hot.

We sealed the attic with 5-6" of open cell (yes, not perfectly "sealed" yet...we have plans for exterior roof work) and it made a fairly significant difference over last year. Not only did we use ~15-20kwh less electricity, the a/c was able to cycle (as it is supposed to) on the hottest days.

We are remodeling and will be air sealing the walls all-around the house, adding some exterior foam as well.

The goal is to flatten our energy usage year round as much as possible to be able to "predict" running autonomously.

 

[NC_hydro]

If I was embarking on this project I would get dual Victron Quattro 10,000VA’s and go with at least 4 if not 6 15kw, 304Ah Trophy batteries. You’re off grid and will have a well, Low Frequency inverter is the way to go. If not Victron, then a Schneider, Outback or SMA. Check out current connected they have some kits you could do and add batteries from Trophy. Trophy is in SC so you could pickup in person and save some shipping. You seem like someone that would like everything to just work after setup, getting a good Tier1 LF inverter is worth the extra.

 

[Zwy]

For the new well, use an inverter Grundfos pump. When my well pump needs replacing, I will use an inverter pump. I can power the current pump just fine but if my wife has many loads running at once, I could see where an overload on the inverters could occur at pump startup.

As for a Sol Ark system, I'd look at what Ian has in a package deal and just add more battery and one more 15K. https://watts247.com/product/ul-lis...o4-batteries-pallet-17kw-550w-bluesun-panels/ Add in a Sinclair ground mount and you will be under the $50K if you do the work yourself.

 

[Quattrohead]

Low frequency inverters are on their way out along with AC motors, everything is being replaced with DC drives slowly but surely and for very good reason too. AC motors have served us well, they were very clever and efficient when new a hundred years ago but now they are hopelessly inefficient and inadequate. Just like horses got replaced with cars lol.

 

[Quattrohead]

Can the solark and sok batteries be fully controlled by a small simple RSD button?
For a new build the fire department is still going to want a simple one step process to kill power to the whole house and this is achievable now with the EG4 18k and it's paired battery or the newest LL rack batteries. Hit the little RSD button and the whole lot shuts down. Easy peasy. I have just had plans approved with this system.

 

[GuyG]

Cost to run electrical to property would be upwards of $60,000

Keep in mind that under the Inflation Reduction Act, putting $60,000 toward an off-grid solar system will give you a 30% tax credit. Seems like a no-brainer to go with Solar instead of paying Entergy 60 grand for the privilege of paying them an ongoing monthly power bill and suffering through their outages.

For off-grid I’d recommend at least 60 KWH in batteries, maybe more. You could build four 15 KWH batteries yourself for about $10,000, or buy them off the shelf for $15-20 K. Those costs likewise get you the IRA tax credit.

Good luck. Keep us posted.

 

[Pericon]

Just a couple of notes. I have a similar situation in Florida but although we have Electric Utility service we will be going Off-grid or Grid backup in the near future.

Our 3/4 HP well pump pulls about 10.5 amps at 120 volts.

We installed a 48,000 BTU Mini-Spilt system in our 2,100 sq ft home and it was the best thing I've ever done. I agree the Wall units are butt-ugly so we instead opted for 2 ceiling cassettes and 2 Ducted units all serviced by I single 48,00 BTU condenser unit. The cassettes were installed in common rooms kitchen & dinning area, the 2 ducted units served the 2 bedroom areas, each with 2 bedrooms and a bath. The effect was having a completely zoned system that very rarely operated at full capacity. Most days we would run just the kitchen area and on hot days over the summer we occasionally ran the living area. Bedrooms as needed. Hot water, oven/range and dryer all run on LP gas. All lighting is LED. I'm not at the property as I write this so I can't give you exact spec on energy usage but I can tell you that the electric bill averaged $105 dollars/month for the past year. This includes power used by a small "gatehouse" building we have near the front road entrance which has lights, a separate well pump, window AC unit and refrigerator. The only thing I would change about the AC system would be to install 2 24,000 BTU outdoor units instead of the massive 48,000 unit simply because of redundancy. I installed the system myself but did hire a local AC guy to connect the lines, vacuum pump and check out the installation. I would not use Mr. Cool on this type project.

 

[Pericon]

The total cost of the Mini-Split system including all components, duct work, small amount of electrical and including the cost of 2 AC service tech visits was about $11,000. But I did all the labor. The equipment company I used was Pioneer.

 

[Doggydogworld]

Yes, it's doable. And you're gathering the right data.
Start with an energy audit. This page explains the basics and has a link to a handy spreadsheet. The audit helps pin down your total energy use as well as your maximum instantaneous power needs. Both are important.

Heating and A/C will probably dominate your energy consumption, so you want to nail those down as much as possible.

If I did it right, PVwatts says 20,049 kWh a year with the lowest months being November/February with a monthly range of 1200-1350 kWh
We get about 214 days of sun, 114 of those are partly sunny, and 100 of full sun.

That's good data for sizing the solar array, but you need daily variation data to size the battery. Unfortunately it's hard to find good daily solar output data. A neighbor with 10 years of daily solar panel production data would be ideal, but sounds unlikely in your case. You do have relatives there, though. If nothing else, mount a panel on their land this month and collect one winter's worth of data. If 3-5 day cold, cloudy stretches are common you'll want more battery and/or a way to heat the whole house with propane.

Cloudy stretches in summer aren't as big a deal, because clouds greatly reduce A/C consumption. But clouds in winter increase heating needs. So it's a double whammy -- less solar production just when you need more heat. A backup propane heater sounds like a good idea (maybe the fireplace insert is enough?). A way to route waste heat from the generator into the house during winter would be even slicker.

You're wise to consider expansion. You can start with a minimum system and just run the generator more often the first year. Then use that data to decide if you need to expand the array, the batteries or both.

Reliability and serviceability are key. If something breaks you must be able to fix it quickly. You want a vendor who picks up the phone and has parts in stock vs. having to order them from China. Look into redundancy. Dual MPPTs, inverters, etc. are great if you can reconfigure them and limp along on a single unit when necessary.

Also during most week days, we would be gone from the house until the evening due to work/school. Our shop will be located at inlaw’s house and the kids would come home to there until we would go home for the evening. So the usage load during this time would be minimal, other than putting appliances on timers to get day loads done while we are out.

This could help a lot with A/C in the summer. It also gave me a screwball idea. You could get an EV with bi-directional charging, charge it up at the shop during the day then use it to supplement your home battery at night. You're paying 13-14k for a 40 kWh home battery. You can find 2019 Nissan Leafs with 62 kWh batteries for not much more than that. They make great 2nd cars for commuting and errands (200+ mile range). And they can save you $1000++ a year on fuel.

Look into geothermal heat pumps. They cost more, but might save money on the solar side of your budget. Especially since you have to drill a well anyway.

I recommend a radiant barrier in the roof and maybe some walls to reduce A/C load. Your contractor may already have that in the plans. South facing windows with solar screens or shutters can reduce your winter heating load without adding much to A/C load. Thermal mass can help you punch through a couple day cold snap. Big slab, brick exterior, etc. Or an indoor pool, ha! Thermal mass also lets you "pre-cool" the house directly from solar during the day then let it "coast" at night instead of running all night on battery.

 

[redalertdt]

Your in the ballpark. I would up the batteries if possible. 100kwh is comfortable and only running generator during winter time (2-3 months).

I'm at 12kw solar and 100kwh batteries and need a bit more solar. No gas appliances though, but high efficiency electric appliances, and a pellet stove and generator in the winter.

Not sure sizing for the Solark, but it sounds about right to me.

 

[KauaiMolokai]

Hi Millpondhouse,
Congratulations. You can definitely do this. Check out Engineer775 on youtube and see if he'll help you. You will get dozens of different, sometimes conflicting, opinions as you research this. If you're interested in importing various components direct from China, send me a private message - you click or hover on my name and start conversation. This can save you a lot on components. In any case, go for it. It will be a learning curve and not without challenges, but you'll do it!!