Backup Heat for Small, Tight House
We have a 1,300 sq ft ranch, reasonably insulated, and pretty air tight (1.6 ACH50). We’re heating it with a Mr. Cool 18,000 BTU mini split, with some small supplemental baseboard heat in distant bedrooms. (Manual J says our house needs 16,000 BTU for heating at 99%, and that has seemed pretty accurate.) But we don’t have any backup heat for when power goes out.
I would love to have a direct vent propane heater (ones that look like a wood stove), but they are too expensive to install and to heat with. And any real wood stove would simply roast us out of the house, and I think we’re way too air tight for that.
We’re considering using a small pellet stove, thermostatically controlled, with a battery backup and an outside air intake vent. But I’m concerned that an intake vent may still not provide enough fresh air in this situation.
Anybody have any suggestions on backup heat options for us? We do plan to get a small generator and some batteries for a few items in the house, but that won’t be enough to help much with heat. Thanks.
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How often do you lose power and for how long?
How about one of those tank-top propane heaters that go on a barbeque tank? They put out 15K BTU/hr. They run for 28 hours on a tank of propane. They cost about forty bucks.
Debra,
If you can wait a few days, I've got an article in the works that addresses this very issue! The short of it, is that you can probably add a small portable generator setup for about $1k or less that will be sufficient to power your entire home, since it's small, and air tight.
I wouldn't be concerned with 1.6 ACH being too tight for a wood burning appliance but you should have a plan in place for make up air if necessary. My home is 1.2 ACH and I have no issue with my wood stove.
A wood stove sized between 20K-30K BTU that's EPA certified could work. Newer stoves have impressively small clearance to combustible surfaces and long burn times that don't roast you out like stoves from previous generations. They burn much cleaner with secondary/tertiary combustion. Catalyst equipped versions also exist that have a marginal improvement in emissions at the cost of replacing catalytic converters. Vt. Castings Aspen model comes to mind and there are others too, quality it not what it used to be with many cast iron stoves, beware, plate steel stoves also exist. Enough 6 inch Class A chimney pipe for a single story home will cost $2250 including ceiling/roof penetrations/support and flashing. Total cost with stove and hearth for floor protection and your looking at $5000 labor not included. Opt for stainless steel VS galvanized Class A chimney pipe as the savings aren't meaningful. Federal rebates are available for materials and/or labor upto $2000 I believe. The biggest challenge in a small home is placing the stove so it's not in the path of walking due to the 16 inch hearth extension required in front of stove.
A direct vent propane monitor is a good option, but propane is fairly expensive. Direct vent gives you plenty of options of where to place the unit on an exterior wall and require minimal if no clearance to combustibles. If the monitor has a 110 volt plug in or has a powered exhaust fan it will need a back up power source, preferably from a sine wave generator to protect sensitive electronics. Rinnai makes quality monitors around $2500.
Pellet stoves fit somewhere between the two previous options and have similar challenges with clearance to combustibles, venting requirements and needing a sine wave power source to operate thru outages. Quadrafire makes a quality pellet stove starting at $3000. Rebates may be available. The least maintenance of the three options is propane, along with being the most user friendly.
As far as back up power sources, Honda makes the best portable sine wave generators starting around $1000.
A portable power station (PPS) is also a good option to run a pellet stove, propane monitor or fridge, but you'll need a way to recharge the unit about every 12 hours and a sine wave generator is the preferred method due to the lithium battery electronics. They can charge in about an hour and offer pass-thru charging which allows the PPS to be used while being recharged. Look for models with lifepo4 battery chemistry VS NCM Li-ion chemistry and a battery capacity of 1000 watt hours or greater. Ecoflow and Bluetti make quality products starting around $1000.
Debra,
Power outages are rare. If you have a power outage, it shouldn't be particularly difficult to crack open a window for more fresh air ventilation or to supply combustion air to a wood stove or pellet stove. Just common sense -- and it's only for a few hours (or a few days at worst).
The cost of propane is also irrelevant. If you decide to install a propane space heater with through-the-wall venting -- that's what I used for years -- I'm sure that you can afford the propane if you are only using the heater for a few hours per year.
The easiest option is a small generator to run that minisplit. A typical box store "screamer" (small generator) is usually around 4-5kw, which is enough to run that minisplit and possibly up to two space heaters if you push it a little (you have to make sure to have one space heater on each "side" of the generator, not on the same 120v circuit). You can setup a small manual transfer switch and power inlet (like a male plug in a weatherproof box that mounts on the outside of the home) easily for the minisplit, or do things a little nicer with one of the Reliance Controls manual transfer switches that can also run a few circuits in your house for some lights and a space heater or two in the remote bedrooms.
If power outages in your area are rare, that small generator setup is probably all you really need, and it has the advantage of being able to run more than just some heat. It's nice to have some lights and a radio or TV that can run during a power outage. A system like this is probably around $3,000 or so installed, much less if you can do the installation yourself.
Fuel costs for the generator, or for any backup heater, are irrelevant here -- you won't use them that often, and when you do, the alternative is freeze proofing your house and staying in a hotel room. Even if you pay a few hundred bucks in fuel every few years, that's really not all that much.
I would not bother with batteries for backup power. They have very poor energy density, so while they can be useful to "ride through" short outages, they aren't very useful for extended outages (hours to days). If you're in an area with infrequent power outages, that means if you have an outage where you really need your backup system, it's likely to be one of the unusual lengthy outages due to a major storm or some other severe event.
BTW, if you go with a small generator, do be sure to do annual maintenance on the unit. That means run it at least every few months or so, and do yearly oil changes. Many homeowners get a generator, run it once to test, then put it in the garage and leave it there. For years. Then one day, they have a power outage, and they think "yay! We're PREPARED! We have a GENERATOR!". But they can't get it to start -- the fuel has degraded and gummed up the carb, the oil is questionable, and mice built a nest in the unit and chewed up the wiring harness. Bummer.
Bill
DC: Unfortunately, I don't tolerate unvented propane or kerosene. It gives me massive headaches. We've only been here for one year. We've had one short outage so far, but friends in the area have sometimes gone over a week without power.
Kyle: I'm looking forward to your article!
Capecodhaus: Thanks for sharing all that information. I'll look into those options.
Martin: In addition to the usual less common (though sometimes prolonged) outages, I'm quite concerned about the long-term reliability of our national grid. It desperately needs upgrading, and the 3,000+ local power companies don't have much incentive to do that and so far can't be required to do it, either, from what I hear.
Our national plans to convert vehicles to EV over the next few years will increase the demand on our grid tremendously, not including the plans to try to convert most fossil fuel heating systems to various forms of electric heat pumps. And our grid is very susceptible to various forms of attack, including the one recently in NC. So I'm concerned about the possibility of more frequent outages in the future. I'm not planning to go off grid, just find a way to be prepared for more unreliable power.
Bill: Thanks for sharing your suggestions. Our main non-heating concern is our fridge and small freezer. I have a friend that is giving me 3 large solar panels, and I'd like to have a small battery system for that. Maybe. Still need to do more research to see if it's really worth it.
I guess it depends on whether you want the back-up purely for heat (to keep pipes from freezing or to come on automatically if the grid goes down and you're away - again to keep pipes from freezing) or you want the added benefit of "appearances" (ie sitting in front of a fire on a cold night).
If purely for heat to keep pipes from freezing than a direct vent propane heater attached to a thermostat that will turn on only when the indoor temperature drops below a certain point is fine.(some can look like a panel mounted on the wall and really disappear).
If you want more of a "fireplace" look, maybe one of those ethanol fireplaces would work?
https://www.portablefireplace.com/blog/are-ethanol-fireplaces-safe/#:~:text=Yes%2C%20ethanol%20biofuel%20fireplaces%20are%20safe%20to%20burn%20indoors.
Otherwise, you could try a really small Cubic Mini wood stove.
https://cubicminiwoodstoves.com/collections/grizzly-cb-1210
rockies63,
The problem I found when trying to get a wood stove for a very small ADU is that most (like the Cubic ones) are not certified.
Any marine stove like a Cubic is not designed for residential use and is not UL listed. Not to mention it would output a meaningless amount of heat in a home. Another issue is the cost is ridiculously prohibitive compared to a proper certified wood stove.
Debra, three "large solar panels" is probably at most around 900 watts, and that's only when conditions are optimal. There are some larger panels available, but the typical "large" panel is usually around 250-350 watts or so. "large" here is slightly smaller than a 4x8 foot sheet of plywood, If the "large" panels are more around 2x3 feet or so, they are probably 50-100 watt panels, somewhere in that range. Keep that in mind -- it's not a huge amount of power, so the things you can run with those panels alone will be limited, and also remember that if you get power 8 hours out of the day, but need power for 24 hours, you actually "get" less than 1/3 of the power the panels can put out, because it gets spread over the entire day, and the power converters are less than 100% efficient.
Solar on that scale MAY be able to run your freezer, but I wouldn't count on it running much else. I would advise against putting in a sufficiently large battery system just for backup purposes, because batteries are an expensive maintenance item, so it's generally best to avoid them unless you really need them. I work with large battery systems at work (one system I was recently involved with was over half a million pounds worth of lead acid batteries, for example). Most of the people who work with batteries professionally hate the things. Lithium ion batteries are better in some ways, but they have some issues too so there is no free lunch here.
For just the fridge and small freezer, one of the really small Honda inverter generators of around 1kw or so would probably be a nice fit. These units are not terribly expensive, they are relatively lightweight as generators go, and they are *very* fuel efficient. One of those and a few extension cords and you're good to go, although I recommend you also have a gas can or too on hand for some extra fuel. BE SURE to run ANY generator OUTDOORS though, and away from open windows or doors cracked for extension cords. Running in a garage with the overhead door mostly closed is also a bad idea. Carbon monoxide can be a real concern here -- it's easy to be safe, but you do need to take those simple steps to ensure you don't have problems.
I agree with you about power problems becoming more common in the near future. I work with critical systems at work (telecommunications sites, some hospitals), designing backup power systems as a big part of my job. The commercial account reps with the utilities have been advising large industrial customers since at least about 10 years ago now that power reliability will likely decline in the near future. The problem isn't so much "the grid" as it is a general shortage of reliable/controllable generation. There are transmission issues too (the big lines usually on the big metal pylons). The utilities are typically required by statute to maintain certain reliability levels, but they get a lot of pushback whenever they propose a construction project, and that's been going on since the 70s, maybe earlier. They have basically given up pushing hard.
The transition to more electrical vehicles is a big problem, because the capacity to do it on a large scale, in terms of available power supply, is just not there. I recently (a few months ago) calculated how much additional generation and transmission would be required to replace all the gasoline consumed in the state of California. I used EIA numbers for gasoline consumption (and it was a LOT! I was blown away!) for that state alone, and the EIA estimates for miles per gallon fleet averages and miles per kwh for electric vehicles. This assumes all gasoline goes into vehicles, which isn't entirely true, but it's probably close. Anyway, I calculated that they would need DOUBLE the capacity they currently have, just to replace all of only the gasoline fueled vehicles with electric and assuming the same number of miles driven. That's twice as many transmission lines, and twice as much generation. Keep in mind that they currently have power shortages in some areas out there, so they're basically starting out in the red. There is no way that's going to be rectified in the time scale being proposed for electric vehicles to replace gasoline vehicles. It would take decades, plural, to build that much new capacity.
Sorry to get a little offtrack from your original post, but I thought I'd expand a bit on what you were concerned about since I work with this particular industry more than most.
Bill
Just a note as many of you have mentioned generators. Much of the newer electronics around HVAC control will not not run on generator power, and UPS’s installed to power other electronics will switch between line and battery until exhausted. If you are looking for backup power, inverter/generators are a much safer bet. Testing is key if you are not using an inverter/generator.
I maintain a 60 000 BTU fireplace (high efficiency, outside air etc) and it will keep our entire home toasty at -30 C. We don’t use it all that often, but when fired up everyone loves it, particularly our two cats :-) I would consider a small EPA type wood stove for simplicity in your case. They use very little inside air when the door is closed, do not need power to run, and will heat usually for 8-12 hours on a single load. Once they reach temperature there is pretty much zero smoke.
Inverter generators won't have issues running anything, except sometimes things with large motors. Some electronics do have issues with the box store "screamer" generators, since those generators generally have crummy frequency stability and put out a less than ideal sine wave. UPSes can often be set to a low-sensitivity mode to avoid the cycling issue, and furnaces running everything on a 24v control transformer shouldn't have any issues.
Note that larger generators, such as the permanently installed standby units, will be able to power anything, are much more frequency stable since they generally use isochronous speed control instead of a mechanical governor, and they have proper voltage regulators as well.
Bill
Thank you, everyone, for sharing your ideas. It's given me a lot to consider.
Bill, after learning more about the pros, cons, and costs of solar and batteries, I've had to put them on the back burner. The cost is far more than what our budget can allow. I do appreciate you sharing what you've learned about the potential upcoming reliability issues with our electric grid.
Dennis, yes, after reviewing our options, we plan to purchase inverter generators - probably 2, in parallel. Due to our age and arthritis issues, we decided that we want to run these on propane AND have an electric start feature. Unfortunately, I haven't yet been able to find a quality portable inverter generator, with dual fuel and electric start, that offers 240 volt capability. So they won't be able to handle our mini split.
Neither a wood or propane stove fit in our budget, either, right now. (Sigh...) BUT, our heating needs are so low, that for now we could probably just use three 1500 watt space heaters (15,000 BTU) to temporarily heat our home, off the generators.
Two parallel 3500 watt inverter generators will give us 7,000 watts of power. Enough for space heaters, fridge and freezer, lights, computers, etc. If we lose power when we don't need heat, we can run just one generator, to save on fuel. I'm still looking forward to Kyle's article!
Just need to create a short, safe, extremely well ventilated shelter for the generators in our backyard, about 12 feet from the meter panel. And figure out how much propane to store. And learn how to safely tie our generators to our house system. (I did all of the wiring for our new house, including the main panel. So, I think I can figure out connecting the generators.)
If you get a "120/240" generator, keep in mind that you can't just divide out the total wattage to figure out how many space heaters you can use. A 5,000 watt 120/240 volt generator cannot run three 1,500 watt space heaters, for example. The reason is that that 5kw 120/240 generator is electrically like two 2,500 watt generators in series (one for each "leg" of the 240v output), so 120v loads can't total more than 2,500 watts on either leg. That means you can only run two 1,500 watt space heaters, leaving 1kw available on either leg for additional 120v loads, or 2kw for 240v loads. Keep that in mind when sizing your system. If the generator is 120v ONLY, then you won't have this issue, but you also won't have the ability to run any 240v loads.
Why do you want to run on propane? Propane has two issues: lower energy density than gasoline, and less availability of supply for refueling. Propane's major advantage is that it can be stored indefinetely and never degrades. For a small backup system, I would just use gasoline fueled generators to keep things simple.
For your system, you may want to consider an interlock kit for the main panel, which is the cheapest way to implement a manual transfer switch. An interlock kit is a bracket that lets a branch circuit breaker act as a second "main" breaker for a generator input, and the bracket ensures that only one of the two breakers can be in the "on" position at any given time.
BTW, If you're knowledgeable about electrical systems, there are ways to use transformers to get different voltage configurations from a generator, such as deriving a 240v service from a 120v-only generator. That may be an option for you, but it increases the complexity of the system, and the transformers are pretty heavy.
Bill
Bill, it’s not the motors..it’s the controls. The forums are full of similar stories, but my personal experience was with a high efficiency furnace with a touch screen and digital interface. Even after carefully tuning the generator governor rpm and voltage regulator with a Fluke meter, it would not run from a generator. Same thing with the UPS units. A small inverter and all is good.
I suspect the electronics have a very low tolerance for frequency fluctuations. I have zero testing with the permanent installs, but I would hope they would clean sine power. In any case, the inverter generator has zero issues powering anything in the home, including a pretty large collection of automation bits. It also fires up the EVSE unit (with a bonded neutral plug) and charges the EV with no issues.
I’m making the point that you should test all your critical items first as things like the neutral bonding/ EVSE will come up even with an inverter generator depending on how you are connecting it.
I suspect it's power factor corrected power supplies, which are more common in fancier systems and anything that is sold into the European market. Those supplies have to synchronize with the line, and they can't do that if it's not stable. The two big issues small generators have is that the mechanical governor tends to under- and over-shoot, and wobbles around. The other issue is the little gensets tend to use a capacitive voltage "regulator", which makes voltage stability directly dependent on frequency stability. The result is an output waveform that is pretty unstable all around. Small UPSes can usually be made to work on it though, and basic things like lights and tools.
Isochronous speed controls use a seperate speed sensor and an electronic throttle actuator so they hold frequency much more stable. "Real" voltage regulators control the field current in the generator to keep the output voltage stable, rather than relying on magnetic tricks with a capacitor. The result is a much, much more stable and clean output waveform. Those types of generators tend to be larger in terms of capacity, which also helps, since the larger the rotating mass, the less anything changes with the load on the generator varies. I know my 18kw genset at my house runs everything -- including the UPS for the computer stuff -- with no trouble at all. The large units I design and install at work are fine to (and usually hundreds of kilowatts and up into the megawatt range). It's really only the small portable generators that tend to be an issue.
What makes the inverter generators special is that they generate the output waveform electronically, using PWM under microprocessor control. They can then vary the engine speed (which is otherwise mechanically tied to the generator, directly linking engine speed to output frequency), so they can run the engine at whatever is optimum for the load presented. Since the inverter is generating the output waveform, not the mechanical generator itself, the output waveform's voltage, and especially frequency, are held far more stable with load changes compared to a "regular" small generator. I would expect a small inverter generator to be able to run any type load up to the capacity of the generator with no trouble at all, and it would tend to be more fuel efficient while running that load too.
Bill
Malcolm & Capecodhaus: does a wood stove need to be certified or have UL listing?
Although the header for this article states "cookstoves" and the site is focused on Canada more than the US I think under points 1 & 2 they are referring to all wood stoves.
https://www.woodcookstoves.ca/wood-stove-certification-in-canada/
Of course, check with your local bylaw enforcement department and building department first, as well as your installer before buying or installing a non-certified or non UL listed wood stove..
rockies63,
You can not install an un-certified stove or chimney in a house in Canada. Once you cut through the confusing rhetoric, all that site says is the EPA standards don't apply in Canada. They are careful to note you should check with your building code (which precludes their use) and insurance company (which will not cover them) before installing a non-certified stove.
Rockies63,
Depends on enforcement. No you shouldn't, and home insurance would not allow in most residential situations and forget about it in new construction, and they waste a lot of wood and don't burn as clean. Sure there are non approved stoves being used, deep in a rural county with no codes. Plenty of people weld steel plates into stoves in NC, Virginia and everywhere else too probably. Craigslist has tons of this stuff for sale. I've found Yotul and Morso stoves for sale from the 1960s-1970s that are UL listed. Would I install one in my home, probably not. Same goes for stove pipe VS chimney pipe, most people makes their own rules as they see fit, beware of the safe-enough approach VS code minimum.
The experimental approach I have taken at our small (1600 sqft) Northern California home is to install one of those unvented ethanol fireplaces. Ours puts out 12000 BTU while lit.
The claim is that they put out only C02 and H20,
but when I have it lit (so far only for visiting company), I crank the HRV to max and crack windows.
I've not yet had to use it to heat for a power outage, which around here tends to be in the summer and fall (but a lot of people lost power during the recent atmospheric rivers). If I did need to use it during an power outage during the heating season, the idea was to use our backup battery to run the HRV instead of the heat pump.
But, it's an experiment in progress which I don't know if I'll ever get a chance to test - my family wouldn't take kindly to my attempting a simulation 😁.
Several years ago, we got a 7000 watt Honda gasoline inverter generator, wired to an outdoor receptacle that is connected to our electric panel. It runs our two minisplits, our induction cooktop, well pump and the usual lights,tv , etc. It'll run our HPWH too. If we're careful, we can even use the electric oven.
We all need electricity, not just for heat, but to run the other stuff too. We need more than just supplemental heat.
I have an Empire dv-35 direct vent propane wall furnace that has no electric requirement and heats my 720sqft drafty house in zone 6 with ease. Willams makes similar models to Empire that have no electric requirement unless you opt to install a fan. They're direct vent heaters that have a sealed plenum and utilize outside air for combustion. Take a look at these heaters. They're an excellent choice for backup heat during power outages.
My mother-in-law had one of those installed a couple of years ago in her off-grid house and it's been great. No more running over there to keep the woodstove going when she's not home!
An overview of various models.
https://www.pickhvac.com/space-heater/types/vented-propane/
https://www.hvac.com/resources/best-vented-propane-heaters-2022-reviews-tips-and-troubleshooting/
An Empire direct vent would be my first choice (don't install an unvented gas or propane wall furnace that uses indoor air for combustion and produces toxins that go into the room!). Empire also has a high-efficiency DV-20 model.
http://empirezoneheat.com/wp-content/uploads/2020/10/00044_070119_HighEfficientDV.pdf
There's also the really cool looking Martin Direct vent Wall Heaters.
https://martinproducts.store/shop/ols/categories/direct-vent-heaters
And ones from Rinnai.
https://www.rinnai.ca/residential/direct-vent-furnaces
From US Stove
https://www.usstove.com/gas-stoves-fireplaces/11000-btu-direct-vent-propane-heater/
Any other great options available?
rockies63,
Those Martins look nice. We had an Empire and it worked well, but they look like something from the 1950s, and there isn't much you can do to smarten them up.
I've been doing tons of more research about our options over the last few days. Here's some of what I found out:
1) I communicated with Quadra-Fire about their Outfitter 1 pellet stove, sharing the details about my house and my concerns about if the outside air intake would be good enough in my tight house. Their technicians discussed my case, and said that they could not recommend that I use the pellet stove in my situation. This was the only pellet stove that I felt was small enough and more affordable (with a good company), but I've also read quite a few complaints about the quality of this stove.
2) I sat down and created a small spreadsheet to compare features/fuel/run times for several different inverter generators, primarily Champion and Honda. My target was to have backup for just 2 days of power outage.
My idea for 2 parallel propane generators (<3500 watts each) turned out not to be realistic, if I wanted to use 3 small space heaters. Cost about $2,500 to buy and install. Those combined inverter generators could use (at full load) more than 80 gallons of propane in just 2 days. There are a number of issues for us leasing a tank large enough to handle this, and we can't physically handle 100 lb tanks (and we could need 4 of them for just 2 days of backup). And it could cost over $300 of fuel for just 2 days!
I checked out a Honda inverter generator (5500 watts), which uses gas and has an electric start. But it would cost over $5,500 to purchase and install. (Yikes!) But it has a 240 volt feature, which could run our mini split and other essential items. But for a 2 day backup, we would need to store 40 gallons (8 five-gallon jugs), AND we'd need to go outside into severe weather or in the middle of the night to refill the generator as it only lasts 6 hours at full load. And we've had bad experiences with gasoline generators in the past, so I really don't like them.
3) I can look a bit more into direct vent propane heaters, but again, we don't have a good location on our property to lease a tank large enough to provide adequate fuel (among other issues).
4) We're considering the Jotul 602 V2 wood stove. Small, very efficient, and sort of adequate for the job. Unfortunately, burn time is only a few hours - we'd need to reload it in the middle of the night, but at least it would be inside work! Still trying to work out fresh air requirements for it. Haven't yet found any other good tiny stoves with decently long burn times. Unfortunately, where we live, we don't have dealers for many of the better brands of stoves.
This stove only costs about $1,600 BUT as another person said here, the stove pipe is much more expensive than the stove itself. Still looking for a slightly more affordable source for it. At least I can install it all myself. And I would only need one small generator for some essential items in the house, which wouldn't need nearly as much fuel.
I really appreciate everyone thoughts and suggestions. I'm diligently researching more information about them. Thanks!
Propane -- or any fuel -- will provide about five times as much heat burned directly as it will if you use it to power a generator and use the generator output to provide heat. An efficiency of 20% would be really good for a generator.
As I noted above, a 15,000 BTU/hour propane heater will run for 28 hours on a 20-pound tank of propane. That's the tank you use for a barbecue, the one you can refill at any hardware store and many gas stations. A couple of those would probably be enough.
Thanks, DC. I'll see if I can decide which heater would suit us best.
Debra,
I don't have experience with The Outfitter 1 and 2 pellet stoves. They are somewhat new to the product line. I have owned two Santa Fe pellet stoves from Quadrafire, they are solid, reliable stoves. I've put over 400 bags of pellets over four years in the first Santa Fe before selling that home. It was the primary source of heat while living in New England. Never needed any repair except a door gasket. I've had no issue with make up air either and in the case of the Santa Fe the optional (MUA) kit doesn't attach directly to the combustion chamber meaning its not sealed and mimicks leaving a window ajar and is very inefficient overall for any home year round. Manufacturers love to cut holes in peoples air barrier for some reason.
In my new home, I use the Santa Fe for back up heat, and I previously powered it from my Honda EU2200 inverter generator. I currently power it from a 1000 watt hour PPS from Ecoflow. I've reduced generator run time from 24 hours a day to about 3 hours. A huge savings in gasoline and no generator running thru the night. I keep 10 gallons of gasoline in a shed.
The Santa Fe doesn't qualify for Federal rebates due to slightly worse emissions compared to the Outfitter, but the BTU output is identical. I take the emissions rating with a grain of salt.
I favor propane or wood burning stove over a pellet stove for back up heat.
The larger Honda inverter generators are impressive units but they are hungry for fuel regardless how efficient they've become thru the use of fuel injection etc.
The Yotul 602 has been around for decades and will roast with a BTU rating of 15k-50k compared to the more controlled Vt. Castings Aspen at 25k. Im not picking favorites but I do like the Yotul, its also tiny in size and can look a bit odd in a small to medium sized space. Quality has taken a dip overtime also like many things. The Yotul barely achieved the efficiency threshold to claim a federal rebate also. Many people prefer the Yotul because it will get very hot and you can cook on it, the Vt. Castings runs about 100-150 degrees cooler but will burn longer. http://www.Northlineexpress.com is where I quoted you for chimney pipe and related parts and is the best online source.
My vote is propane and a large enough tank permanently installed somewhere on your property if possible. Regardless of decision, your spending somewhere between $4k-$7K. It becomes more a decision about about ease of use, reliability, maintenance and comfort in the end.
If you are concerned about your physical ability to move fuel around, that is a big concern for a wood stove or pellet stove too. Heating with wood has some advantages here, especially if you have plenty of wood from your own land, but the big downside is it is a LOT OF WORK, especially if you have to chop wood for a conventional wood stove. I haven't ever used a pellet stove, but I would expect similar amounts of effort to move equivalent amounts of wood around, just without the need to chop and season the wood. Wood is heavy, and you have to keep "refueling" as you burn the wood. Keep that in mind.
Honda's small generators are generally considered to be the best on the market, but you pay for that. Champion and similar are generally not as reliable or long lived, but they are significantly cheaper. There are always tradeoffs.
Since you mentioned your primary concern is your freezer, not heat, I would consider Honda's 2200 or 3200 watt inverter genertors, which are a bit under 50 pounds for the smaller one, and about 60 pounds for the larger one. Either is said to run for around 8 hours with variable load. The small one would be nearly maxxed out with a single 1,500 watt space heater, but the larger run could run a heater and your freezer plus a little extra, although it's still only 120v output so no minisplit operation without some transformer mojo.
Don't try to store large amounts of gasoline at home. Gasoline degrades rather quickly, and is hazardous to store. What I would recommend here would be to have a few gas cans on hand, and maybe something smaller than the typical 5 gallon can to make it easier for your to handle (a full 5 gallon gas can is around 40 pounds or so). Keep some gas on hand when you expect outages, but otherwise store only a minimal amount -- and be sure to put stabilizer in any fuel you intend to store. When you expect a storm is coming, maybe fill a gas can. If you actually have an outage, you can usually go out and find gas stations to buy more fuel from as needed, so that you don't have to store large amounts at home. Any fuel left over in your gas cans after the power is restored you can just put in your car since the generators use the same fuel as most cars. This way you don't waste any fuel. You can keep the generator on a furniture dolly to make it easier to move around when you're not using it.
Typical generator loading is less than full load, so you'll get more runtime with lighter loads. The space heaters would be the only thing likely to really guzzel the fuel, but you're still probably looking at refueling at least every 10-12 hours or so, but that's less frequently than with a wood stove. You can run your generator in a sheltered area, such as a car port, and sometimes a garage with the overhead door FULLY OPEN, although it's recommended to run the generator completely outdoors. What I've done for people before is build a simple lean-to shed with legs and no walls, to act as a weather shield for a portable generator. This makes refueling easier.
If you go with propane, you have the advantage of a fuel that can be stored indefinetely without risk of degredation, and you can order fuel deliveries (note that in major diasasters, propane deliveries tend to be harder to get though). If you're in a cold area, you need to size the tank not just for runtime, but also to be able to provide sufficient gas flow in BTUs at the lowest outdoor temperature you expect. If you have a tank sized too small for the gas flow at cold temperatures, you won't be able to "boil off" enough gas to feed your generator, which will cause the generator to be starved for fuel. Keep that in mind. Any company that can supply and install a propane tank should be able to help you with sizing for this.
Now you have the issue with a propane generator: an electrical AND a fuel hookup. I would go with a permanently installed generator here, and not try to use one of the dual/tri fuel generators that can run on gasoline or propane. The reason is that the fuel hookup is an extra step. The permanent standby generators are fully automatic, so you don't have to do anything, and they tend to be better quality generators too (no issues running loads, longer life, etc.). I prefer Kohler's small residential units over Generacs, due to Kohler having better quality in my experience. Cost is similar, but Generac has a bigger dealer network. Either way, you typically want an automatic transfer switch with one of these units, so the installation costs are going to be higher, probably $5k+ to buy and install, excluding the propane tanks (which can usually be leased, BTW). The advantage to this installation is that you don't have to go outside AT ALL in a storm to deal with the generator, you can run for days unattended, and the generator is likely to be large enough (usually at least 7kw) to be able to run your minisplit normally along with other things in your house. For a typical house, I recommend about a 10-12kw unit which will normally be enough to let you run "as if power wasn't out", although code now requires some load management to be installed in many cases (depends on the loads, but the equipment isn't terribly expensive). Remember that these permanently installed units still need annual maintenance, which is mostly "fluids and filters": air filter check, oil filter replacement, and oil change. The usual rule is "every year or every 100 hours of runtime, whichever comes first" for an oil change. You can contract this work out, and it's not very expensive to have done if you don't want to it yourself. You can get the oil and oil filter you need at any auto parts store as the generators use common stuff.
Obviously I'm partial to backup generators :-) I install them as part of my work, but usually for large commercial sites. They offer the big advantage of being able to run everything in your home and not ONLY heat. DC is right about it being inefficient to burn fuel to make electricity to make heat, since you lose energy every time you convert it between forms, but remember that this is a BACKUP system, that will only run a relatively small amount of time, so overall efficiency isn't as important. In the case of your heat pump, you still have the advantage of whatever the COP is on that unit too, so it will be better than DC's ratio, since his ~80% loss (it's probably worse than that) would only apply if using the generator to heat with electric resistance, such as space heater.
Bill
Bill, do you know if the "whole-home" automatic backup generators can be installed to be manually operated via connection to an interlock kit? Something like this one: https://www.generac.com/all-products/generators/home-backup-generators/guardian-series/10kw-7171-wifi-enabled
Or is installing them as full-blown automatic transfer the only option for these sorts of units?
I ask because this particular unit is quiet (61 dB) but higher output than most of the "portable" 240v generators. I don't want to incur the cost of doing a full-blown automatic backup setup with transfer switches and all, but I've already got a 240v 30-amp inlet connected to an interlock kit.
The answer is "it depends". If the generator supports the industry standard "two wire start" interface, then all you need to do is wire the power output of the generator to the input of the interlock kit, then put a simple on/off switch on the 2 wire start circuit. When your power fails, flip that switch on the start circuit (it just needs to short the two wires together), let the generator start and get up to speed (which should take under 10 seconds), then do the transfer procedure with the interlock kit. When utility power is restored, first do the retransfer procedure with the interlock kit, then give the generator at least about a 5 minute cooldown period (which it might do automatically), then flip off the "generator start" switch to open the 2 wire start circuit and shut down the generator. Easy. All a traditional ATS would do is close the 2 wire start circuit when power fails, then transfer, and reverse the procedure when power is restored, all with some handy time delays to make things work smoothly.
The tricky part is that many of the residential standby generators, and as far as I know, that includes ALL of Generac's residential line, use a fancy interface between the ATS and the generator since the generator is also the "brain" of the ATS. In a traditional system, the ATS has it's own brain and operates independetly from the generator except for the simple 2 wire start interface. With these fancier systems, you have to use the ATS that matches the generator system you're using. What do you gain with this fancier system? Typically nothing -- it's a cost cutting move on the part of the manufacturer. I'm not sure if such a system can be made to work with a manual interlock, you'd have to check to see if the generator had a 2 wire start interface in addition to the fancy ATS interface, and if it does, you should be able to wire it as I described earlier and just not use the fancy ATS. I don't like these fancier systems.
I know Kohler also has this fancy ATS issue, but they also make some units that run with a 2 wire start system. I would check with them too.
BTW, ALL of the residential standby generators are typically much better, and quieter, than the small box store "screamer" generators. While I'm not a fan of the Generac units, they too are significantly better than a typical portable generator.
Note that you would need to hardwire any of the standby generators, you would not use the 30A inlet the way you would with a portable generator. You would be able to use the interlock kit for the breaker box though. Keep in mind that the standby generator will also need a 120v power circuit to run the battery tender, and possibly a heater too to help it start in cold weather. I typically recommend running the battery tender on a seperate circuit from any heater (less risk of the battery draining that way), but it's not entirely necassary to keep them seperate.
Bill
Great answer, thanks. Makes me think it would probably just be easier to get something like the Honda EU7000is if manual use is the intended use.
Our local power is very reliable but recently utility has been replacing poles and overhead wires in the neighborhood which meant occasional power outage. There are a couple of houses around me that have the full size outdoor hard wired backup generators running off natural gas so I got to hear them operate. I would not call any of it quiet, this is the last thing you would want outside your window overnight.
Stick to a nice inverter generator that will put out both 120/240. If your utility allows it, check out Generlink meter mounted ATS.
Interesting, thanks for mentioning the Generlink. Seems kind of similar to an interlock kit + generator inlet? Except doesn't take up any breaker slots in your main panel and the Generlink itself is what senses whether you are getting grid power or not to enable or disable the generator inlet?
Edit: Contacted GenerLink and was informed that my power company does not allow their product to be installed. Oh well.
For emergency use you may want to consider a diesel heater made for campers with a battery pack to power it. Some have been know to feed them waste motor oil knowing it will clog the heater with soot faster. Yes, I understand it is not listed for use in a building desperate time call for desperate measures.
https://www.amazon.com/Fiberfly-Muffler-Parking-Thermostat-Motor-home/dp/B08GHM583V/ref=sr_1_46?keywords=Waste%2BOil%2BHeater&qid=1675185944&sr=8-46&ufe=app_do%3Aamzn1.fos.f5122f16-c3e8-4386-bf32-63e904010ad0&th=1
Being prepared is great but it is almost certainly wasted money as the likelihood of a power outage lasting so long that the pipes in a petty good house would freezes is very small.
The idea that the electric car is going to crash the grid sounds like chicken little proclaiming the sky is falling to my ears.
Walta
>"The idea that the electric car is going to crash the grid sounds like chicken little proclaiming the sky is falling to my ears."
I recommend then that you look up the numbers (most info is available on the EIA's website, the rest on the websites for the various ISOs). You can convert the gasoline consumption data into kilowatt hour equivalents, then compared that to grid supplies. My calculations were more involved than this (I allowed for charging during off peak hours and many other things to make my numbers as favorable as possible to the "grid will be OK" side of things).
What you basically end up with is an issue of scale. For a simple and quick conceptual thing, lets just do a simple version of this. Statista says there were about 276.5 million cars in the US in 2019. Let's assume only 20% of those will actually be driving around (being conservative) on any given day, and only those will need to charge. Let's use my Chevy Volt's consumption info as a guide, which will use 3kw for about 6 hours to get a charge good for a typical day's commute (around 20-25 miles or so).
We have 55.3 million cars charging, drawing about 3kw per car. That works out to 165,900 megawatts. That's megawatts, not megawatt hours, because we're talking about the total load presented to the grid. For some perspective on how much load that is, the ENTIRE generating capacity of the major electric utility in Southeast Michigan (DTE Energy) is about 11,000 megawatts. Even if we divide that number of cars out by 50 states, we have 3,318 additional megawatts per state -- but in reality it won't divide out evenly, because some states have more population, and more vehicles, than others. People in states with lower populations my drive longer commutes on average too, which might make things worse. At any given time, the utilities are powering other things, taking plants offline for maintenance, etc, etc, so what you end up with, even with my very conservative estimate here, is a total additional new load that is more than the typical available additional generation available for any utility at any given time. Utilities don't have this amount of excess capacity, since it is unreasonable to overbuild that much.
So the short answer is, no, "THE" electric car isn't going to crash the grid. The problem is when you try to scale up to have many/most people driving electric cars, then the TOTAL of ALL of those is a problem. Over a sufficiently long period of time it's doable, but the arbitrary and short timelines usually proposed are not realistic.
Bill
> . You can convert the gasoline consumption data into kilowatt hour equivalents, then compared that to grid supplies.
I hope you are not directly using the 33.7 kWh of energy in each gallon of gasoline, since ICE vehicles are only 20% efficient on a wells to wheels basis.
> Let's use my Chevy Volt's consumption info as a guide, which will use 3kw for about 6 hours to get a charge good for a typical day's commute (around 20-25 miles or so).
18kWh for 22.5 miles? That's 1.25miles/kWh, which doesn't make sense since the Volt routinely achieves 3.2mi/kWh, so many times more efficient. Even the truly ridiculous Hummer EV gets 1.6 miles per kWh. 3rd generation EVs will start approaching 6-10miles/kWh by further optimizing weight and simplifying drivetrains.
> Utilities don't have this amount of excess capacity, since it is unreasonable to overbuild that much.
It's not going to be powered by excess capacity. It's going to be powered by capacity growth. It is also going to be reasonable because they will have new predictable load in the form of EVs, coupled with smart charging that spreads load over longer periods of time.
I was using EIA's numbers for mileage equivalence, which is for comparison purposes between EVs and ICE vechicles. The Volt numbers are from what I've seen, and remember that charging isn't 100% efficient, and it also heats or cools the battery while charging, which uses additional power. What you get out of the battery for driving around (the "real" watts per mile), is less than what you put in when you charge. I think the volt is in the high 200s to low 300s watts per mile as you mentioned, when driving and using battery charge. It takes more than that to charge, and as it's aged (my Volt is about 10 years old now, and still going strong), it's taken more charger watt hours per output battery watt hours.
Yep, powered by capacity growth that IS NOT THERE, and is NOT being built at the scale required, if at all. And if you spread out the load of charging, you're doing load leveling. That doesn't help as much as you'd think, because most of the extra capacity is available at night, irrespective of where it is sourced from, because that's when load is lightest. That's why so-called "time of day" rates are cheaper at nights, and on weekends. Most charging is going to be done at night, which is a good thing, but also means the numbers are big. Minute-by-minute load adjustments don't matter, since the scale of the grid already does that statistically.
I've attached a graph of the MISO ISO's load right now. That double-hump is only in the winter, in the summer, it's more of a smooth sinewave-like curve.
It doesn't really matter how the charging is controlled in terms of the supply required, because when you have millions of people charging, it already averages out somewhat. Yes, smart technologies will help, such as allowing more chargers to start charging as grid loads drop later in the day, but the simple reality is that none of that is enough to make up for the MASSIVE total increase in electrical consumption that will result from the switch to EVs on a large scale.
Bill
walta100,
"Yes, I understand it is not listed for use in a building desperate time call for desperate measures"
What desperate times? Debra is planning for future power outages, not the apocalypse. Recommending appliances that aren't rated for use in a building is bad advice.
Debra, it looks like you are now considering two entirely different systems - a supplemental heating system for emergencies and a supplemental electrical backup system (ie a generator).
I think a small propane generator would be an excellent idea for those rare events when the grid goes down but I think you are putting too much thought (and money) into your potential choices for supplemental heating.
A pellet stove and a wood stove are both very expensive, time consuming, and messy choices, especially if you only plan on using them for a few days a year during an emergency (plus they take up a lot of square footage within the home). Most of the time they will just sit there unused.
I also think you're over-estimating the amount of time it takes for a warm house to cool down and get to the point where pipes could freeze. if your home is well built, well air sealed and well insulated then several days can pass and your home will still be comfortable. Still, if there is a point where the heat is off for a week or more (and you're not getting any solar heat gain through south facing windows) then a small direct vent propane wall heater is the best way to go, especially if it is set up with a thermostat to only come on when the indoor temperature falls below a certain point. The goal isn't to keep the whole house at 72 degrees for a week or more, it's to keep things above freezing until your main system comes back online. After all, this is only for emergencies.
I mean this sincerely - how about some nice mummy sleeping bags? Cheap, no air quality issues, no space constraints, lightweight and 100% reliable. Backup heat sources are all compromises - at least this compromise is cheap!
In addition to having some sleeping bags handy, what about adding heat to the house from small sections of in floor electric powered by a battery? Note, I am not suggesting heating the whole house to a desired temperature, just adding enough to raise the temperature to levels tolerable with extra clothes and blankets.
Thanks!
Ben
You won't get enough power from a battery of reasonable size to make any significant difference in the temperature of the house over any appreciable period of time. For some perspective, a typical car battery, if running a typical 1,500 watt space heater with a 100% efficient inverter (which doesn't actually exist, so we're being overly optimistic here), will be able to run that heater for about half an hour, and probably less than that.
Batteries just don't have very good energy density, unfortunately, which is why they are not normally used for backup systems that need to run more than a few hours at most, and usually battery backup systems are used for applications needing well under an hour of runtime.
Bill
Hi Debra,
I thought I would provide the approach I took since I am building our house at the moment. For similar reason as you Debra, I wanted ways to be able to provide heat and power during outage.
I installed a small wood stove with a SBI damper outdoor air intake and a generator panel. I just purchased a portable generator since it was cheaper and I can also use it on or off the property.
Thank you,
Arnold
It sounds like you're in a pretty airtight, well-insulated home, which is great for energy efficiency, but definitely presents some challenges when it comes to backup heat options. A pellet stove with a battery backup and outside air intake is a solid option, though I can understand your concerns about fresh air. You might want to look into Belle Flame’s (https://belleflame.com/) line of direct-vent pellet stoves. They are designed to be very efficient and safe for tight homes because they draw air for combustion from outside, preventing you from needing to open windows or doors for fresh air. Plus, they have good thermostatic control and some models can run on battery power for a period of time, making them a good fit for backup heat during power outages. Just something to consider!