Home Backup Power Systems

[Larry Caldwell]

I have leaned heavily on technology that does not require electricity. The wood stove provides heat in winter outages and low head water allows flushing and cooking without electricity. I installed a 60 amp transfer switch to power the water heater and well pump for showers, plus refrigerator and freezer. The generator is a 6500w propane electric start. A top of the line lithium battery UPS will keep the modem and router up for at least 12 hours between generator runs.

I have spent far more on energy efficiency than on backup power. New doors and windows, plus Hunter-Douglas fitted cellular blinds for the windows, roll-up awning for a full glass double door on the south side to cut summer heat and allow winter solar gain. Insulated the attic, subfloor, plumbing, and ductwork.

We have a mild climate. Average winter nighttime heating is only 40 degrees, often only 30 degrees. Maximum summer cooling is only 30 degrees, and the heat pump doesn't kick on until 3:30 PM on the hottest days, 6 PM if it only gets to 90. We could be fairly comfortable without AC. If I lived in a more severe climate, I would make very different decisions. Thanks to geology, I have a poor site for solar, though I do have a couple acres of 100% slope south facing bare rock a couple hundred yards from the house.

My choices are also a lifestyle decision. The silence of a winter outage is glorious. The last thing I want is to listen to the sound of a generator, so I try to minimize runtime as much as possible. Before I bought the UPS I used a little ultra-muffled 1000w camp generator to keep the electronics up. It wasn't too obnoxious on the other end of a 100' extension cord. If you are beset by neighbor noise, silence might not even be a consideration for you.

 

[dmccarty]

I have been around and around and around on this issue.

So to skip to what I would do today, go to the last two paragraphs. The rest of this long post is how I got to the last two paragraphs.

When we first bought the land, well before we owned land, I thought that having a passive solar home with solar panels was they thing to do. When we designed our house, it was sited to maximize solar power and passive solar heat gain.

The problem back then was the limitations with lead acid batteries. I had kept up with solar power technology for decades, and maybe 20 years ago, went to a class taught by a local developer who built a quite a few homes with solar power. Lead acid batteries were a limitation but also the NC system for paying for surplus power production. Basically, back then, and now, it is not worth over producing power to sell to the grid. Just not worth it.

I have recorded every power build we have had since we moved into the house two decades ago. Our power bill has gone from 8 cents to a maximum of 18 cents per kilowatt hour. This includes the cost of power, taxes and fees. The highest payment was 18 cents but that was a one off when we built the house, and the recent cost has been 16/17 cents a kilowatt hour. That is a long winded way of saying saying our cost for power has gone up very little, compared to how much money we can make in the stock market. I could never justify spending money on a solar power system.

In the class I took, we lost quite a few "students" when they found out that they could not just put up some solar panels and have power during a power outage. They just got up and left. The solar panel and inverter costs are only part of a back up solution since one needs batteries. Lead acid batteries were just really expensive back then, and even today, but there are better solutions now.

While all of this was going on the with the house, we became interesting in buying a boat and seeing the world. Solar power production and energy storage is a much bigger problem/solution on boats than in houses. LiFePo batteries have greatly changed boating. Simply a game changer. If we build a boat, it would have 7,000+ watts of solar power, at least 25kwh of battery storage, and maybe around 100kwh and hybrid propulsion.

I have not looked at the power wall solutions in years. What turned me off to them was they were Lithium batteries and one could not charge with a generator. That is absurd. There are many Lithium battery chemistries but the safest is LiFePo. I would not use any battery chemistry in a house or boat other than LiFePo.

Over the years, even though we are rural, we have only lost power for more than 12-25 hours 2-3 times. It has been a PITA for sure, but money wise, it does not make sense to spend tens of thousands of dollars to provide power for a few day of outages. Part of our power backup system is a wood stove which easily heats the house. When I had time to make firewood, we heated the house full time with the wood stove. I plan to get back to heating the house with the wood stove. We really miss it and forgot how well it worked. We started the wood stove for the first time in years this month and we had forgotten how well it heated the house. <sigh>

Today, if I was going to put in a back up power system, I would buy Victron inverter/chargers and LiFePo batteries. Victron equipment is used in RV, boats, and homes to provide power and they have a well integrated system to do so. Having the batteries charged by the grid, solar, or generators is what Victron equipment is setup to do and does world wide on boats, houses and RVs. No need to be limited by the power wall companies. LiFePo batteries are not 100% safe but they are the best that is out there right now. They can still produce explosive gases if over charged but nothing like other Lithium battery chemistry. Having said that, I would put the batteries in their own enclosure away from the house. No way am I hanging a power wall with Lithium batteries on the house. Not happening.

With Victron, and there are similar companies out there, one can charge the batteries with the grid, a generator, solar, or even wind. Since our power outages are mostly 12 hours or so, we could build a battery system that could easily provide power for these shorter time frame outages, but we could also simply add more batteries to provide power for longer periods of time. Just a question of money.

 

[orezok]

When I built my system here in the desert, it was the most efficient both production and cost effective. It’s a ground mount system that I installed myself. I’m a GC so no issue. We have a 2450SF all electric house. Annually (2025) my 7530 watt solar system produced 15.4 kW in ‘25 and I consumed 17.1 kW for the year. My annual settle up with SCE has been $1200 for the last 2 years. $100 a month is hard to beat. It’s necessary when summer temps go above 115º. I looked at batteries which are very expensive, the ROI would never make sense at $100 a month electric cost.

We did install a 22kW Generac for the longer term outages as we are old and don’t tolerate excessive summer heat without AC.

 

[ultrarunner]

I’ve seen some expat off grid million dollar properties on 40 acres or so…

The only monthly house expense is satellite internet…

Those that have designed their systems are very pleased…

I confess that for a long time I would check my surplus solar generation from the day before… it was rare for me not to have a slight surplus from my 6kW ground mount and every year at true up I receive a few hundred which easily covered the $15 monthly meter fee…

I expect this to change under the equity legislation where solar producers will have much higher monthly fee plus for new producers almost no buyback income…

 

[hayden]

Today, if I was going to put in a back up power system, I would buy Victron inverter/chargers and LiFePo batteries. Victron equipment is used in RV, boats, and homes to provide power and they have a well integrated system to do so. Having the batteries charged by the grid, solar, or generators is what Victron equipment is setup to do and does world wide on boats, houses and RVs. No need to be limited by the power wall companies. LiFePo batteries are not 100% safe but they are the best that is out there right now. They can still produce explosive gases if over charged but nothing like other Lithium battery chemistry. Having said that, I would put the batteries in their own enclosure away from the house. No way am I hanging a power wall with Lithium batteries on the house. Not happening.

With Victron, and there are similar companies out there, one can charge the batteries with the grid, a generator, solar, or even wind. Since our power outages are mostly 12 hours or so, we could build a battery system that could easily provide power for these shorter time frame outages, but we could also simply add more batteries to provide power for longer periods of time. Just a question of money.

This is how my off-grid house is powered, with solar as the primary power source, and backup diesel generator. I have only 30 hrs on the generator so far this winter, and it never runs spring, summer, and fall.

 

[Larry Caldwell]

This is how my off-grid house is powered, with solar as the primary power source, and backup diesel generator. I have only 30 hrs on the generator so far this winter, and it never runs spring, summer, and fall.

I have less than 5 hours on my backup generator 4 years. Right now the south windows are warming the house just fine. Spending thousands on a backup system is absurd if all you need is to run a water heater and well pump. For everything else, electricity is a convenience, not a necessity.

 

[ning]

I have an Enphase grid-tie battery+solar setup. Fantastic for occasional not-too-long outages in winter, or longer ones in summer. If we had a bad power outage during winter storms, even at basic household use the batteries probably wouldn't last two full days, but as long as I don't turn on AC I shouldn't have any problems mid-spring through mid-fall (fall actually being when we've had our worst power outages at our place, due to wildfire power line destruction or proactive shut-off).

I intend to add a propane generator (we have large tanks and more and more don't use a lot of it as I've had a lot of wood to burn) that can be used to recharge the batteries. There may be incentive/tax issues with directly charging from fossil fuels, but I think in a grid outage it could be argued that it's an emergency situation.

I wouldn't rely on an automatic whole-house backup generator as those will be running 24/7 (I did say automatic) and if you're on propane, you'll run your tank dry in nothing flat. That happened to a lot of people around here three years ago - they ran out of propane within days and then had no heat and no electricity, and many roads were impassable for a couple weeks and the propane deliveries either impossible or backed up for weeks.

Presumably TBNers wouldn't fall victim to this by manually scheduling running of the generator... presumably. (I've warned my newer neighbors about this as they inherited a full-house automatic system which I hear kick on when the power goes out; so far I don't think we've had long enough outages and they're also so frazzled with their busy lives that I don't think they've noticed just how much propane that takes.)

I do think a whole-house backup generator, in conjunction with batteries, is the ideal situation, at least until we get sealed buried nuclear power generators. As @ponytug mentioned, most generators run most efficiently near full load, and if you size your generator to your battery recharge needs, you can have plenty of electricity, quietly for most of the day, and only a few hours a day have the generator run to recharge (my system can be programmed to kick on the generator when battery levels drop to some low point, and have the generator turn off once it regains some amount of charge, plus prioritizing generator quiet times). I haven't installed this yet, but it's on the list...

 

[TractorTYMe]

I have a Generlink power meter auto switch generator system. It goes between power meter and wall. And supports up to a 12Kwh portable generator. I'm all and all $2200 into my home emergency power setup.

 

[grsthegreat]

I have a 22 kw propane generac. Love it….abd best part of it it was free.

I sold and installed so many of these, the promotions kept piling up and i was able to get either this one for free or i could have gotten a liquid cooled 22 kw for maybe an additional $1000 or so out of pocket. But i trust the air cooled more than the liquid cooled after all the issues i was seeing with customers liquid cooled units.

9 years later….. 1 battery plus annual maintenance.

Being a generac service tech…. I have all parts for it ill ever need.

 

[BackRoad]

I have a 22 kw propane generac. Love it….abd best part of it it was free.

I sold and installed so many of these, the promotions kept piling up and i was able to get either this one for free or i could have gotten a liquid cooled 22 kw for maybe an additional $1000 or so out of pocket. But i trust the air cooled more than the liquid cooled after all the issues i was seeing with customers liquid cooled units.

9 years later….. 1 battery plus annual maintenance.

Being a generac service tech…. I have all parts for it ill ever need.

Mr. GRS, you are the Generac Oracle, interested in your guidance on the air cooled vs. liquid cooled issues...I would have placed to liquid cooled to be a better unit above the air cooled just for life expectancy.

Was it a bad design that's been since changed, or do the liquid cooled still have gremlins?

The air cooled are reported to be louder? Is that noticeable to you?

Are there other material differences between the air or liquid cooled with similar capacity?

 

[grsthegreat]

Mr. GRS, you are the Generac Oracle, interested in your guidance on the air cooled vs. liquid cooled issues...i would have placed to liquid cooled to be a better unit above the air cooled just for life expectancy.

Was it a bad design that's been since changed, or do the liquid cooled still have gremlins?

The air cooled are reported to be louder? Is that noticeable to you?

Are there other material differences between the air or liquid cooled with similar capacity?

Im not saying liquid cooled is bad, but if there is a problem, cost is magnitudes higher…. The generac line has way too many sensors. And there too finicky. The worst 2 are the cam pulse sensor and the water level sensor. The cam sensor is always causing no starts, lots of the time just from crud sticking to it. PITA getting late night calls on this. But worse is the water level sensor. I swear let the radiator get 1/10” low and generator shuts down. These sensors also get a coating of crap accumulate on them and shut down.

Not all liquid cooled run at 1800 rpm. The 45 kw generac runs at 3600 rpm and sounds so loud i have to wear hearing protection when standing and working on one (like 3 of the aircooled 22kw units running at same time) Whereas the 48 kw is about half as noisy as it spins at 1800 rpm.

For people that experience rare outages the liquid cooled are not necessary in my minds eye. But some people in their mega mansions insist on having warm towels during outages and need big a** generators. I have one customer with a 130kw unit that sucks down 19 of propane PER HOUR.

I think the evolution1 and 2 series are a great generator for occasional power outages. There not meant to run for weeks on end or off grid situations. But for occasional use there great units. There easy to maintain and very reliable.

If it wasnt for the hassle of diesel storage, a diesel 1800 rpm generator is the best of both worlds. Quiet and last forever. Dont seem to have the same issues of their gas relatives. But man, are they expensive. And you best have a good diesel mechanic available. You cant haul them into the service dealer.

My biggest dread is generac has changed their entire air cooled lineup. New units have lots of sensors, fuel injection modules, dual this and that….and hydraulic valves. The engines are actually smaller than the trusted 999cc, and they now are all hydraulic valves. No more digital control panels, there cellular and bluetooth controlled. They let the techs take over, and im just not happy.

 

[D&D]

I have an Enphase grid-tie battery+solar setup. Fantastic for occasional not-too-long outages in winter, or longer ones in summer. If we had a bad power outage during winter storms, even at basic household use the batteries probably wouldn't last two full days, but as long as I don't turn on AC I shouldn't have any problems mid-spring through mid-fall (fall actually being when we've had our worst power outages at our place, due to wildfire power line destruction or proactive shut-off).

I intend to add a propane generator (we have large tanks and more and more don't use a lot of it as I've had a lot of wood to burn) that can be used to recharge the batteries. There may be incentive/tax issues with directly charging from fossil fuels, but I think in a grid outage it could be argued that it's an emergency situation.

I wouldn't rely on an automatic whole-house backup generator as those will be running 24/7 (I did say automatic) and if you're on propane, you'll run your tank dry in nothing flat. That happened to a lot of people around here three years ago - they ran out of propane within days and then had no heat and no electricity, and many roads were impassable for a couple weeks and the propane deliveries either impossible or backed up for weeks.

Presumably TBNers wouldn't fall victim to this by manually scheduling running of the generator... presumably. (I've warned my newer neighbors about this as they inherited a full-house automatic system which I hear kick on when the power goes out; so far I don't think we've had long enough outages and they're also so frazzled with their busy lives that I don't think they've noticed just how much propane that takes.)

I do think a whole-house backup generator, in conjunction with batteries, is the ideal situation, at least until we get sealed buried nuclear power generators. As @ponytug mentioned, most generators run most efficiently near full load, and if you size your generator to your battery recharge needs, you can have plenty of electricity, quietly for most of the day, and only a few hours a day have the generator run to recharge (my system can be programmed to kick on the generator when battery levels drop to some low point, and have the generator turn off once it regains some amount of charge, plus prioritizing generator quiet times). I haven't installed this yet, but it's on the list...

Exactly, most people with whole house generators don’t think to conserve energy and turn the thing off periodically. like the person with a new boat that runs hard all day, then gets mad at themselves for burning $500 of fuel.

 

[BackRoad]

Good...no, GREAT contributions from all...Thank You!

The air cooled vs. liquid cooled discussion is significant. I live in a temperate (was 5b, now 6a) zone and going air cooled rather than liquid may increase reliability, while reducing cost...and headaches.

 

[Carl_NH]

HI Backroad,

Sounds like your on a mission to install a whole house unit similar to us -getting older and after doing cords/generator in 2006, then a whole house portable in 2015, finally to a automatic 8KW Generac on propane in 2025. We have a 1,5 hp well pump FHW oil heat and DHW and gas stove. 8KW is plenty for the house load and AC is not needed 90% of the time.

We got our Generac free from a remodel who wanted an upgrade - 170 hours 2017 model - cost was the installation $6500 which included a propane tank $1K.

Point being, there are a lot of lightly used low hour Generac or similar available for $1-2K and given you have NG already its not a big expense to get a whole house system.

Where abouts is "rural pa" - it's mostly rural! I grew up 20 miles north of Carlise and went to PSU in State College in the 70s then stayed and worked in State College doing farm automation for Agway back then.

 

[BackRoad]

Mr. Carl, we're center of the state East to West, about an hour north of Williamsport up Route 15...Tioga County.

Our land is 1/2 mile south of the NY state border with Corning, NY the closest real grocery store.

 

[Carl_NH]

Know the area a bit - have a customer in Wellsboro I've been to several times - Trucklite, then spent my first 6 years in Elk County - Wilcox area on a farm, still have forest land there. Rt 6 is a great road to travel in PA

 

[mikester]

2. Is there new emerging technology that might be worth considering (such as a Powerwall)?

3. Are there emerging technology or systems that should be avoided?

I thought the powerwall sounded interesting until I read it needs an active internet connection to work.

We have more frequent internet outages with starlink than we have power outages.

 

[duffer]

A word of caution for those of you thinking of adding a Generac whole house system. A couple of years ago, they opened up a new plant in Trenton, SC. I actually worked there for 91 days. I can tell you from 1st hand experience there is no quality control, or training in that plant. (nor any effort to improve their systems/processes. That's why I quit).
There were literally 100's of partial and finished units that failed initial testing sitting in the aisles of the warehouse. (that is not an exaggeration)

The other plants (like the one in Wisconsin) have been established for decade(s). They've worked out the bugs. If you're going to buy one, make sure it does NOT come from SC. They can trace the serial number to see where it was made.

Just my 2¢.

 

[ponytug]

I thought the powerwall sounded interesting until I read it needs an active internet connection to work.

We have more frequent internet outages with starlink than we have power outages.

They can function with cell service or home internet.

We have had powerwalls through a period of intermittent / unreliable internet service. They do need internet to upload the system settings, state of charge and current flows to Tesla servers, but we've been down for a day or more with no issues. IIRC, it was after three days straight of no internet service that it complained. We have zero cell service here.

Once we switched to Starlink, we have had fewer and fewer internet disruptions. These days, it is never an issue. However, I have the Starlink antenna located where it has no obstructions, so the outages have always been on Starlink's side.

FWIW: I just checked seven disruptions of no more than 0.7s in the last 24 hours.

All the best, Peter

 

[grsthegreat]

They can function with cell service or home internet.

We have had powerwalls through a period of intermittent / unreliable internet service. They do need internet to upload the system settings, state of charge and current flows to Tesla servers, but we've been down for a day or more with no issues. IIRC, it was after three days straight of no internet service that it complained. We have zero cell service here.

Once we switched to Starlink, we have had fewer and fewer internet disruptions. These days, it is never an issue. However, I have the Starlink antenna located where it has no obstructions, so the outages have always been on Starlink's side.

FWIW: I just checked seven disruptions of no more than 0.7s in the last 24 hours.

All the best, Peter

Man…no way i want my backup to depend on internet…much less a 3rd party screw up. I had no idea the powerwall had external control.