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Reality Check on Building a Family-Sized Home Off-Grid

djparnell

djparnell

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Joined
Mar 21, 2024
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Location
New York
Hello Everyone,

My name is David. I live in NY, and have property in the Adirondacks that I am building on this year. I am - and have been for a few years - weighing whether or not I want to make this an off-grid build. So, I am reaching out to, well, anyone that will give me their experience with off-grid living to help me make that decision.

My energy needs were calculated based on my family's current avg. energy usage - ~30KWhs per day - and I worked with two different solar engineers to spec out a system. Of course, we factored peak sun hours per day, as they historically occur in my property's zip code. Using 3 days of autonomy, at the lowest avg. sun hours per day (in December), the system came out as: 13KW PV array and ~2000AH of LifePo batteries. Just to be safe, though, I purchased 26KWs of Longi bifacials, thus doubling the array size. Of course, we would have a backup generator as well.

The build will be ~1200 sq. ft., and built very tight, with spray foam insulation.

Why am I considering and off-grid build? I do not have a pole to my property - the nearest being ~1 mile away - and the quote is $180-$200K from National Grid. I know this is a lot, and I am sure that most-if-not-all that are reading this - on this forum, in particular - are thinking "That's ridiculous. Solar is a no-brainer." That said, please consider the rest of my considerations:

(i) When not in use, I will be renting the property. Renters are not energy conscious.

(ii) I will be adding more, but smaller, builds to the property in the future for rental purposes.

(iii) I do NOT want to be constantly thinking about energy usage / conservation when I am using it.

(iv) I do NOT want to be working on the array/inverters/batteries regularly.

(vi) Based on early quotes, between hardware and installation, the solar will cost ~$80 - $100K. This is before tax credits.

With that in mind, and despite my best searching/reading efforts on line, I have yet to find anyone - and I mean, NO ONE - that has said something along the lines of "Well, we have X-size array and Y-sized battery bank, and we never have to worry about power. We threw in central air, and have a hot tub, and we never worry about whether the batteries are drawing down." There seems to always be some discussion about raising the thermostat in the summer during a cloudy stretch; fear of installing heat pumps; no one uses central air - all mini-splits; etc.

So, with that as my back drop, is there anyone on the forum that has (i) built a 1200 ft. + house (not a small cabin) that supports a family, and (ii) has installed a large solar/PV system with a battery back up in the North East that has had a smooth experience? What do I mean by "smooth"? The system, (a) for all intents and purposes run itself without frequent inspection/intervention, and (b) the backup generator only runs, say, 5 or 10 times per year.

If, for instance, I were able to install a system for the cost that I've spec'd, and it ran "smoothly", then I'd likely go with the Solar, and could scale up accordingly for the other builds. But, if real world experience - at a larger scale - finds that the generator is often running, and there are semi-frequent-to-frequent interventions necessary, then I'd likely bite the bullet.

Please know that I write this with a true spirit of inquisition, humility and curiosity. I'd love to have a great off-grid system. Who wouldn’t? But I am building this property as an asset, and with future plans in mind, so I want to do it right the first time, even if that means bending over backwards to do so.

Thank you in advance to anyone that will afford me their time.
 
As far as renters, meter it. Not to make money of course, but if they have to pay something, then they are more likely to conserve and follow rules, like laundry on sunny days, etc.

I wouldn’t do a hot tub, especially with renters.
 
80-100k for 26kw of solar and 110kwh of storage? That's ridiculously expensive and should be no more than about $50k- perhaps a lot less
 
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“I will be adding more, but smaller, builds to the property in the future for rental purposes.”

So I’m guessing you have plenty of land.

Items that can be added onto for future expansion:

Two adjustable Sinclair Design ground mount systems. ~$15,000 delivered

Ex: 100 x 490W TOPCon bifacial panels ~$10,000 delivered.

Inverters that can be paralleled.

10 x 14.3kWh rack batteries ~$12,000 delivered

I think you could have a very nice system for less than $50,000 before any tax credits.
 
Just as you have plumbers and HVAC service people, you can pay for solar service/repairs. Sounds like you are not a DIY guy, but after you get something that offers freedom like solar, you may become more engaged. So many plan on grid power being always there, but that is not always the case. You will need heat backup, right? Might as well use propane for electrical backup while you are at it.

There must be a way to structure renter use of power so that the foolish don't spoil it for the rest.

You have already purchased 26,000W of solar panels? What'cha waitin for?
 
I am in Florida (not always as sunny as you may think) and am just finishing off a self build home of 2600sqft.
It is very well insulated and was always designed around being off grid.
I have 13kw of panels, 1 (soon to be 2) EG4 18Kpv inverters and around 140kwh of batteries.
I have been testing this system for a year in a regular builders grade house of 2000sqft, all electric and had to lean on the grid for backup just a few times.

You already have what seems to be plenty of panels already, you could be light on battery but you can add more easily.
Are you going to use propane for heat, hot water and generator ? Is a generator even necessary ?

It is absolutely doable, go for it.
 
All of this can easily be done if you find some other way than electricity to make heat. Making heat with electricity is inefficient and asking a solar system to do it is compounding the issue. (Edit: I mean any form of resistive heating elements here, not heat pump systems especially the newer and more efficient ones, nor any form of geothermal temperature control.)
You need propane for heating, hot water, cooking, and clothes drying. Once all of that is removed from the electrical panel things get easy.
I don't even know if they make a propane hot tub but running an electric one off of solar is not advised.
My system for this would look like the following:
2x EG4 18k inverters in parallel
4x EG4 PowerPro 14.3kW battery
1x Generac 14kW standby generator controlled by master 18k, starts when battery SOC drops below 30%
Soft start module on AC condenser
I plugged in 26kW at Long Lake, NY (rough center of Adirondacks) into the calculator at https://pvwatts.nrel.gov/ and it shows your LOWEST month is December at nearly 40kWh per day. This is a rack mount at 20 degrees and 180 azimuth, you might want to count on using a ground mount and maybe bifacial panels to maximize production. Your highest use days will be in the summer with the AC running but you will generally be producing more as well. If it is significantly cloudy it shouldn't be very hot.
I recommended the EG4 18Ks because they are feature rich with user settings that allow the system to run automatically without any user input, even starting and running the generator if it is needed.
I am a member of a prepper community and a 25 year licensed electrician, I have designed and installed multiple systems with a similar need and I'm telling you the same thing I told them. I am getting ready to build my retirement house deep in the sticks and it will be a 100% off grid passive solar structure with all DC appliances, which is much more efficient but is also a bit more trouble to manage.
Don't let people make this overly complicated.
 
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There's a couple developing an off-grid home in the Adirondacks - youtube "Creating a Simpler Life Off-Grid" where they're doing a custom earth covered house. They do Solar - Panels, Sol-Ark, propane-gen. Here's a recent recap you might find interesting - they are straight forward folks with honest info.

I run a 15kw PV array (48 panels) in Southern Oregon and it produces about 15,000kwh/year (90kwh/day in spring/summer but only 13kwh/day in mid-winter). Nov+Dec+Jan+Feb is where I have low power issues. The rest of the year is workable. You can size you're system appropriately and in cooperation with propane auto-start generator such as the folks above use.

Suggest PVWatts - https://pvwatts.nrel.gov/pvwatts.php - for my planning, a simple to use site that takes into account you're location / local-weather to make PV output predictions.
 
djparnell said:
Hello Everyone,

My name is David. I live in NY, and have property in the Adirondacks that I am building on this year. I am - and have been for a few years - weighing whether or not I want to make this an off-grid build. So, I am reaching out to, well, anyone that will give me their experience with off-grid living to help me make that decision.

My energy needs were calculated based on my family's current avg. energy usage - ~30KWhs per day - and I worked with two different solar engineers to spec out a system. Of course, we factored peak sun hours per day, as they historically occur in my property's zip code. Using 3 days of autonomy, at the lowest avg. sun hours per day (in December), the system came out as: 13KW PV array and ~2000AH of LifePo batteries. Just to be safe, though, I purchased 26KWs of Longi bifacials, thus doubling the array size. Of course, we would have a backup generator as well.

The build will be ~1200 sq. ft., and built very tight, with spray foam insulation.

Why am I considering and off-grid build? I do not have a pole to my property - the nearest being ~1 mile away - and the quote is $180-$200K from National Grid. I know this is a lot, and I am sure that most-if-not-all that are reading this - on this forum, in particular - are thinking "That's ridiculous. Solar is a no-brainer." That said, please consider the rest of my considerations:

(i) When not in use, I will be renting the property. Renters are not energy conscious.

(ii) I will be adding more, but smaller, builds to the property in the future for rental purposes.

(iii) I do NOT want to be constantly thinking about energy usage / conservation when I am using it.

(iv) I do NOT want to be working on the array/inverters/batteries regularly.

(vi) Based on early quotes, between hardware and installation, the solar will cost ~$80 - $100K. This is before tax credits.

With that in mind, and despite my best searching/reading efforts on line, I have yet to find anyone - and I mean, NO ONE - that has said something along the lines of "Well, we have X-size array and Y-sized battery bank, and we never have to worry about power. We threw in central air, and have a hot tub, and we never worry about whether the batteries are drawing down." There seems to always be some discussion about raising the thermostat in the summer during a cloudy stretch; fear of installing heat pumps; no one uses central air - all mini-splits; etc.

So, with that as my back drop, is there anyone on the forum that has (i) built a 1200 ft. + house (not a small cabin) that supports a family, and (ii) has installed a large solar/PV system with a battery back up in the North East that has had a smooth experience? What do I mean by "smooth"? The system, (a) for all intents and purposes run itself without frequent inspection/intervention, and (b) the backup generator only runs, say, 5 or 10 times per year.

If, for instance, I were able to install a system for the cost that I've spec'd, and it ran "smoothly", then I'd likely go with the Solar, and could scale up accordingly for the other builds. But, if real world experience - at a larger scale - finds that the generator is often running, and there are semi-frequent-to-frequent interventions necessary, then I'd likely bite the bullet.

Please know that I write this with a true spirit of inquisition, humility and curiosity. I'd love to have a great off-grid system. Who wouldn’t? But I am building this property as an asset, and with future plans in mind, so I want to do it right the first time, even if that means bending over backwards to do so.

Thank you in advance to anyone that will afford me their time.
Click to expand...
I love the idea of a 1200 sq ft place…and the area…and your willingness to spend big bucks…
BUT… coming from a family that had many rental property’s , short and long term, the thought of hoping renters will exercise good judgement and behavior with a very large solar system and use it property scares me to death…
as they know you have to maintain it as the landlord , prudent behavior is not a front burner issue.

Maybe the system will run perfect and need no supervision …or experience…or even knowledge.

But ….Maybe not…

I will leave the technical side to others but in my experience after watching what my my elders went through, renters are sorta like mice… there is no way to anticipate what they are capable of doing or the mess they can create…
It defies even trying to describe…..

Jus my 2cts worth.

J.
 
My house is only off grid for about 10-16 hours a day in the summer, and a few hours every other day or so in the winter, and we micro-manage it, so my thoughts and usage should be taken with a grain of salt as compared with your desired situation.

Thoughts:

Your average daily use you suggest is "energy" use but I'm worried it might just be electrical use. Have you factored in heating, cooktop, water heating, dryer, and other appliances that sometimes use gas? Are you planning to have gas available for those things in your proposed home?

Have you considered other loads - electric car or plug in hybrid charging, for instance - that you or your guests might bring? Additional installed features such as a pool or hottub?

I find that a lot of solar calculators overestimate solar production at a given site, with panels at a specific angle. Further, they don't seem to provide worst case analysis - which is what you need.

Assuming your 2,000AH of battery is with 48V batteries, and your 26kw of solar panels are angled correctly, then I believe those will meet your bare minimum 30kwh/day with a 3 day latency. I'd suggest adding more solar panels - for my house (southeast michigan) I'd need closer to 31kw of solar to meet our needs fully in the dead of winter.

But the kicker is you want the system to be self managing. I think, then, what you need is to multiply portions of the system to add redundancy, and get to know a local electrician who would be willing and able to get to know your system and perform emergency service as needed.

The generators need to handle both the full property load and charging the batteries - so they only have to run for several hours a day rather than all the time. If one goes out then the other should be enough to run the property and slowly charge the batteries.

I'd add another 20-30% solar panels and charge controllers so if one portion of the array goes out - equipment failure, environmental damage, animals chewing on tasty wires, etc - then your system will still handle the overall load.

Likewise I'd suggest several inverters ganged together, with at least 20-30% overhead so one can die and it won't affect your energy usage at all.

If possible, consider splitting the batteries into banks that each have their own charge controllers, inverter(s), etc so a battery failure won't cascade.

With a generator running 5 times a year, you're asking for 98% uptime. That's entirely possible in an off grid solar system, but you will need a rather complicated system with multiple redundancies, and getting the right electrician on board is going to be crucial. Better still, getting a solar contractor you can trust with on-call service and remote monitoring might fit your needs better particularly since you'll have situations where property damage can occur when it's unattended - winter and pipes, etc - but also if you do choose to rent to others.

But keep in mind - a single 120v outlet charging an electric car, particularly one that's just traveled 150 miles to the adirondacks - can consume 43kwh/day. If there's at all, ever, a possibility someone will try to charge their car using your power system, even through a limited 120v outlet, then you'll need to either 1) detect that situation and handle it with a smart breaker panel (cuts off power to a circuit if it's consuming an abnormal amount of power) or 2) resize your system to support up to 80kwh of additional load per day per car, or 3) recognize that you are using an off grid system and you will have to consider loads and educate renters. Someone leaves a room heater on high all day and there goes 29kwh of your system capacity and likely during the winter when your system is at it's lowest capture rate. That's only $5 of electricity, but it'll require you to invest 2-3 thousand times as much initially to support that one errant load.

Having a central dashboard that indicates current power usage, power hogs, and estimated time remaining given projected solar collection, current consumption, and battery charge level might be enough to give you confidence to use a small system in a worry free off grid configuration, but if you truly want to never consider it, and use electricity as though it were grid connected (which can supply 576kwh per day to the small homes with only a 100A service) then your system will need to be larger.

If you need to add electric heat/cooling (even with a heat pump), or an electric dryer, or you plan on using rechargeable power tools for lawn maintenance, then you'll need to revisit your consumption estimate.

Lastly, unless the solar panels are very nearly vertical, you're going to have to do snow and ice removal in the worst parts of winter.

It can all be done, but I've seen a LOT of people who started off grid eventually add a pole because they didn't fully understand their energy usage and all the outliers that may only occur a few times a month, but make solar untenable, on top of the maintenance and constant care.

A week of thick clouds and -3F temperatures will really test your resolve - make sure your generators are up to snuff in cold weather.

A system with 4-way redundancy (four inverter/battery/solar panel/charge controller/generator sets, mostly independent but coordinated), and at least 33% more power than you need in your worst case scenario (someone's turned up the heat, has a portable heater running, and is charging two vehicles through 120v outlets), plus an on-call electrician will probably give you the reliability and thoughtlessness of the grid. 40kwh of battery per set, 12kva of inverter per set, 30kw of solar per set.

You can, of course, start off with what you have, which is essentially one set of the system described above, and then expand as long as you buy the right components to start so that expanding each time is straightforward, and the power building(s) are built to support the additional components you'll eventually need.

It's overkill, but that's what's necessary for a system you want to treat like you'd treat the grid.
 
JRH said:
had many rental property’s , short and long term, the thought of hoping renters will exercise good judgement and behavior with a very large solar system and use it property scares me to death…
Click to expand...
Yeah, I had to pay for oil on a 2 family with a shared heating system. The renters used the windows as a thermostat.
It didn't take long under my ownership for the oil heat to break and be replaced with baseboard per unit.
 
My advice/opinion will be worth every penny you paid for it:

You should have a block outbuilding for your power plant. Generator inverters, switching etc. Leave room to expand your plant, vent it and lock it so the renters cannot get in. Spend some time designing this, and have bypass capability. Generator needs to be big enough to handle 150% of your average load or better. You will want to feed it into the inverters to supplement/charge batteries as necessary. This will provide seamless output for the primary dwelling via the inverters. You will want to over-provision your inverters to handle demand. I would go with 3 or 4 12K output units (Solark, EG4, whatever) 50A each. This will give you the needed overhead to not worry about tripping the main breaker. (150-200A service). Whatever you get for batteries it will never be enough, thus in your building design I would design for full size equipment racks of 50KWH and start with 1 rack. Your propane tank will need to be big enough to run the genny for a week. Objective is to never use it of course. Ground mount all your panels if feasible. 28KW is a good start, engineer space/conduit/etc to double it. Depends on how much time you want to run the generator, and/or how much battery you are willing to buy.

From time to time you may need to take various things offline, put in the needed switching to feed power independently from your generator to the dwelling. For example to do a scheduled firmware upgrade on the inverters, flip the dwelling breakers for the high-load devices, engage the genny & switch to it, do the upgrade, reverse the procedure. Run the 240v service from the building to a panel in the house, just like the power company would. Add a manual 200A transfer switch in front to tie another source in there should things change, or something go horribly wrong, you can flip it and hook something up direct. $15K for batteries, $20-30K for the inverters, likely another $5K for the wire and conduit.

I've been gradually moving my setup to this nirvana. Like you, my idea is I don't wish to change my lifestyle just because I put in solar. I have not used the grid since February, and I don't want to spend time "managing" my system. Maintenance and testing (scheduled) is fine. Your also going to want to monitor and get alerts when things are not as expected. You should excercise the generator and get reports, and test your failover scenarios and alerts before renting it out. You will need to respond rapidly should there be an issue, figure out what you might need, store it in your outbuilding.

Let us know what you end up doing.
 
Thanks so much to everyone so far!

The locale is Lyonsdale, NY, and I have 30 acres on the Moose River.

Avg. daily sun during summer is 4.13 hrs (peak months are June/July at 5.3), Avg. winter sun is 2.65 (bottom is Dec. at 2.3).

Panels were ~$8K (Got a steal in Ebay - brand new Longi 375W bifacials)
Batteries - ~$14K (From Amy Luan - quote). I would likely opt for something closer to home, though, with the thought of better support and quicker turnaround if there are issues.
Battery Racks - ?
Inverters - 2 EG4 18 KPVs - ~$10K
Charge controllers - ~6 @ ~$250 - $1500
Sinclair ground mounts (adjustable) - 2 X 36 panels = ~$10500
Generator (15KW EcoGen) - ~$5K
Off site insulated building to house equipment - ~5K
Wire/conduit - There will be ~300 ft. b/t PV array and building. Unsure, but expect this to be ~$2-3K

Installation - I am careful to not put the quotes I've received for installation into public view without having taken contract.

So, equipment - if I went with Amy Luan - would be ~$57K. If I did something like EG4 LP4s (48V @ 100 AH) X 20 (to get the 2000AHs), ~$23K, which would put equipment at $~66K.

If I took the lowest installation quote, I'd be over $100K for the installation. And that's without considering any ancillaries.

So, it sounds like air conditioning wouldn't be the worst issue. I will be heating with propane - ideally a hydronic system. But again, based on the forums, there is quite a bit of negativity on running pumps.
 
Being up north, I’d look into geothermal heat pump for heating and cooling.
 
Snaketzu said:
All of this can easily be done if you find some other way than electricity to make heat. Making heat with electricity is inefficient and asking a solar system to do it is compounding the issue.
Click to expand...
Disagree. I'd have a propane heat backup, but variable speed heat pumps today will heat a room very efficiently without extreme electric usage.
Snaketzu said:
You need propane for heating, hot water, cooking, and clothes drying. Once all of that is removed from the electrical panel things get easy.
I don't even know if they make a propane hot tub but running an electric one off of solar is not advised.
Click to expand...
I disagree. I would build my home all-electric, induction range all electric, standard electric HWH. I would not use a demand HWH unit.
Snaketzu said:
I plugged in 26kW at Long Lake, NY (rough center of Adirondacks) into the calculator at https://pvwatts.nrel.gov/ and it shows your LOWEST month is December at nearly 40kWh per day.
Click to expand...
This might be wishful thinking. I have 20kw of panels in Phoenix. Somewhat sunnier than New England. I February I had a 1 week period where my average was closer to 25. I also had days over 80. The sun doesn't subscribe to that web site, and you may be running the generator for a week at a stretch with abysmal weather. Plan for it.

Again the objective is seamless/hands-off. I'd consider in-floor heating with multiple/redundant loops with both electric and propane heat available, but I think mini-splits and a propane/wood-stove in the living room for emergency backup heat + ambiance would be lower maintenance.

The problem most people have is demand not average daily kwh. Build out the inverters for demand, add on panels and batteries as needed to meet consumption goals. I put it as "who cares" if I can produce the power need via solar. All the creative stuff you see is to work around demand, but if you look at usage an electric range (for example) generally doesn't consume squat over a month. Even a regular old hot water heater is not that significant. Turn it all on with a microwave, a toaster oven, and a blow dryer, and now you have a demand problem if you don't have enough inverter. I charge two (2) EV's which creates 7600KW of demand for hours. That is a lot of consumption,10% of one car charge (40 min) is roughly a load of laundry, hot water, wash, and electric dry. With my current build I want a third inverter which gets rid of my demand monitoring. I will have a slight increase in solar production from replacing some used panels in a few months up to around 24KW. 60KW of batteries seems to do well but at some point I will want 90

In New England, your overall usage, on an all electric home should be significantly lower than what I use, even with winter heating, I live in a brick (not verneer) home with minimal insulation. Over build to what I will have you should be able to run your power plant and not even think about it. It's all about DEMAND! Increasing production or storage is simple enough once you can meet your demand. If you have access to inexpensive fossil fuels (wood, oil, propane, etc) I'd drop storage, but all those organic heat sources come with a caveat: The price can go up.
 
Op I admire your ambition. Personally, I’d pay not to be in an off grid situation with renters.

If the cash flow works I might go for the line. But that seems unlikely.

Is there any neighbor you can share the cost with?

The only other alternative I can think of is to run a smaller line with a lower ampacity. Use it to charge a large battery bank 24/7.
 
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