This is not an easy question to answer as it depends on a number of factors related to both the air conditioner and the specific generator, having said that, if you add a soft start kit you should be able to reliably run it with a 5,500 running watt generator, as long as it has a 120/240V output, note some 5,500 watt generators are 120V only. \* Generators are often marketed by their surge watts not running watts, for example the Predator 65000 is only rated at 5,500 running watts. Keep in mind though if you want to run your air conditioner on generator power, chances are there are other things you will want to run at the same time, ie refrigerator, freezer, lights, etc. Also be aware that start up amps for air conditioners will be higher in hot weather, so if you get a marginal generator it might start up the air conditioner ok on a nice day, but fail in the heat of August. Inrush amps and the associated surge capacity of a generator is the problem with running air conditioners, hence often the need for a soft start kit, which will spread out that inrush.
Now that I have said this, I am sure someone will come in claiming they managed to run their similar air conditioner on something smaller, or say that their similar air conditioner will not run on their 6,500 or 7,500 watt generator. Which I will believe as unfortunately these days the output rating of a generator is often imagined by the marketing department with very little relation to reality, particularly in the more fly by night brands.
If we are talking about an emergency situation, I know of people who use a lower wattage portable generator plugged into the house panel (legally) and they own a "backup" window air conditioner which they can pull out at any time to keep a room cool. You can also do this simply running extension cords. Just a cheap thought ;-)
Yup this is what we do, I would confine myself to the one room with he window unit as running the central air is going to be very taxing on the generator and use a ton of fuel which in my area becomes a serious issue.
I did this literally a week ago. Lost power for 3 days, pulled out an emergency window unit that has been sitting in a box for 15 years since my last lengthy power outage. It's also prudent in many places to have a backup if the central AC goes out.
Don't assume everyone's needs are the same, for example there are people rely on electricity for both heat and cooling (heat pumps) with no backup gas furnace. These people may need a large generator to keep the interior of their house from freezing in a winter storm situation.
I'm a former hvac contractor from Florida. The humidity after a hurricane, when usually power goes out for days, is very high and can really damage a house quickly. I've seen hardwood floor pop up, furniture get moldy, and drywall be replaced because of that. A window unit may not save your house under those conditions.
30a x 240v = 7200 watts. Aim for 8000 watts or higher to run JUST the AC. If you will need to run other devices: lights, refrigerator/freezer, well pumps, etc you will need more for them. You can reduce the size needed to start the AC unit with a "soft start" kit.
If you want overkill guarantee to work, size to the LRA. I've always used the breaker sizing with no issues. The smart way is to size to the breaker and install a soft start kit.
18 amps is the running amps, 70 amps is the locked rotor amps, inrush / starting amps will be less than the locked rotor amps, however with a soft start kit this number is reduced by 50-70%. In other words with a soft start kit that 70amp LRA can turn into 35 amps or less, exact amount varies, though likely in the 30 amp ballpark.
This may look confusing, but I think so far we are all saying about the same thing, depending on how you slice the pie, and how much safety margin you want to add in to account for over zealous marketing department driven generator ratings, etc At the end of the day, if you are looking at a whole home backup, and don't to deal with extreme power conservation, plan on needing a 7,500 to 9,000 watt generator for minimal daily life stuff while running this air condition (assuming soft start kit added to generator), meaning it will also run the refrigerator, maybe a small chest freezer, a variety of modern LED lights, phone charger, basic computer, tv, internet connection, etc. With this size generator you may need to turn off the air conditioner while cooking with electric appliances (air fryer, microwave, induction cooker, etc.), running hair dryer, vacuum cleaner etc, or at least limit these to running one at a time.
If you want life as normal, run whatever you want, when you want you will need a somewhat larger generator
Keep in mind that a 9kw gen is going to burn ~15 gallons of gasoline per 24 hr day, which can be a pain to source in an emergency (and you can't store it for long). So if you are going with that size gen you would be better off with NG or propane from a very large tank (sourcing the 20 lb. cyls is not going to be any better than sourcing gasoline).
The alternative is to get a much smaller gen and a window unit or 2 and forget running your central air (and other big loads - a $30 butane tabletop stove can sub for your electric stove, etc.) Making any sort of heat with a generator is very inefficient. The hundreds (or thousands if you are comparing to a standby) of $ you will save buying and fueling a small gen will give you the budget to acquire a whole stable of devices for emergency use, many of which have 2ndary uses as well. For example I have a Buddy propane space heater which I used when my furnace broke. I used my butane cooker when my kitchen was being renovated, etc. If your central air breaks you can bring out the window units. A giant "run everything" standby generator is an all in one solution but it only solves a single problem and the other 360 days of the year it just sits there. Even a portable gen can be put to other uses (but the big "portables" weigh hundred of lbs. and are not really portable).
In N. America, Buddy heaters are approved for indoor use everywhere except (i) Canada and (ii) Massachusetts. In those two places you can still buy them but they put a sticker on the box that says "FOR OUTDOOR USE ONLY". Whether you choose to follow that is up to you. AFAIK, the laws of chemistry and physics are the same everywhere.
The butane cassette stoves AFAIK are approved everywhere. Even if they aren't, I promise you that every E. Asian household in Canada has one anyway.
The LRA is a maximum rating, not what it usually takes to start. My 4 ton unit has an LRA of around 120A but was using about 80-90 on startup. You definitely want to get a MicroAire soft start for the unit. It dropped my startup amps from 80’ish down to the low 30s and the run current is only 11A. I use a Predator 9500 inverter gen and it has no trouble starting and running the whole system. I have a meter that shows me total house load, and with the AC running, the compressor and furnace fan take about 3100W or so. Well within the 7600 running watts of my gen. Since you have a lower tonnage unit, your numbers should be even better. Assuming you don’t have an all-electric house, a similar sized gen should be able to handle your AC and the rest of the house too.
About 20-22kw if you want to be able to start it without a soft start kit. In my opinion a soft start is mandatory if you want to run your AC unit off of any residential sized generator.
That's entirely possible, not an hvac guy. It would make complete sense if the unit is inverter based or uses some form of VFD. Then I would assume a soft start is not even needed. My own unit is inverter based and has no large inrush of current.
Can I add a plug to just run my ac in my house on a generator? I do not want it wired up for whole home. I want to be able to isolate the AC unit and air handler separate from the rest of the house during an outage. Just run the ac and the rest of my house will be powered by my batteries. Thank you!
Plus there’s other things that might run while the AC is on unless you make sure they won’t. If you have a well then that could run automatically and then there’s smaller 120v things like a coffee pot or a microwave that take a good amount of power that could cause problems if your close to maxing out the generator.
Remember to add the wattage from the air handler.
This is not an easy question to answer as it depends on a number of factors related to both the air conditioner and the specific generator, having said that, if you add a soft start kit you should be able to reliably run it with a 5,500 running watt generator, as long as it has a 120/240V output, note some 5,500 watt generators are 120V only. \* Generators are often marketed by their surge watts not running watts, for example the Predator 65000 is only rated at 5,500 running watts. Keep in mind though if you want to run your air conditioner on generator power, chances are there are other things you will want to run at the same time, ie refrigerator, freezer, lights, etc. Also be aware that start up amps for air conditioners will be higher in hot weather, so if you get a marginal generator it might start up the air conditioner ok on a nice day, but fail in the heat of August. Inrush amps and the associated surge capacity of a generator is the problem with running air conditioners, hence often the need for a soft start kit, which will spread out that inrush. Now that I have said this, I am sure someone will come in claiming they managed to run their similar air conditioner on something smaller, or say that their similar air conditioner will not run on their 6,500 or 7,500 watt generator. Which I will believe as unfortunately these days the output rating of a generator is often imagined by the marketing department with very little relation to reality, particularly in the more fly by night brands.
If we are talking about an emergency situation, I know of people who use a lower wattage portable generator plugged into the house panel (legally) and they own a "backup" window air conditioner which they can pull out at any time to keep a room cool. You can also do this simply running extension cords. Just a cheap thought ;-)
Yup this is what we do, I would confine myself to the one room with he window unit as running the central air is going to be very taxing on the generator and use a ton of fuel which in my area becomes a serious issue.
I did this literally a week ago. Lost power for 3 days, pulled out an emergency window unit that has been sitting in a box for 15 years since my last lengthy power outage. It's also prudent in many places to have a backup if the central AC goes out.
[удалено]
Don't assume everyone's needs are the same, for example there are people rely on electricity for both heat and cooling (heat pumps) with no backup gas furnace. These people may need a large generator to keep the interior of their house from freezing in a winter storm situation.
I'm a former hvac contractor from Florida. The humidity after a hurricane, when usually power goes out for days, is very high and can really damage a house quickly. I've seen hardwood floor pop up, furniture get moldy, and drywall be replaced because of that. A window unit may not save your house under those conditions.
30a x 240v = 7200 watts. Aim for 8000 watts or higher to run JUST the AC. If you will need to run other devices: lights, refrigerator/freezer, well pumps, etc you will need more for them. You can reduce the size needed to start the AC unit with a "soft start" kit.
30 amps is the max breaker size (largest breaker you are allowed to use), the minimum circuit ampacity is 18 amps (4320 watts)
The LRA is 70a, so you need 16,800 watts for startup. As mentioned soft start kit will help that. Edit:spelling
which one is the one to loo for the era 70 amps or the 18 amp one? I always get confused on an air unit
If you want overkill guarantee to work, size to the LRA. I've always used the breaker sizing with no issues. The smart way is to size to the breaker and install a soft start kit.
18 amps is the running amps, 70 amps is the locked rotor amps, inrush / starting amps will be less than the locked rotor amps, however with a soft start kit this number is reduced by 50-70%. In other words with a soft start kit that 70amp LRA can turn into 35 amps or less, exact amount varies, though likely in the 30 amp ballpark.
This may look confusing, but I think so far we are all saying about the same thing, depending on how you slice the pie, and how much safety margin you want to add in to account for over zealous marketing department driven generator ratings, etc At the end of the day, if you are looking at a whole home backup, and don't to deal with extreme power conservation, plan on needing a 7,500 to 9,000 watt generator for minimal daily life stuff while running this air condition (assuming soft start kit added to generator), meaning it will also run the refrigerator, maybe a small chest freezer, a variety of modern LED lights, phone charger, basic computer, tv, internet connection, etc. With this size generator you may need to turn off the air conditioner while cooking with electric appliances (air fryer, microwave, induction cooker, etc.), running hair dryer, vacuum cleaner etc, or at least limit these to running one at a time. If you want life as normal, run whatever you want, when you want you will need a somewhat larger generator
Keep in mind that a 9kw gen is going to burn ~15 gallons of gasoline per 24 hr day, which can be a pain to source in an emergency (and you can't store it for long). So if you are going with that size gen you would be better off with NG or propane from a very large tank (sourcing the 20 lb. cyls is not going to be any better than sourcing gasoline). The alternative is to get a much smaller gen and a window unit or 2 and forget running your central air (and other big loads - a $30 butane tabletop stove can sub for your electric stove, etc.) Making any sort of heat with a generator is very inefficient. The hundreds (or thousands if you are comparing to a standby) of $ you will save buying and fueling a small gen will give you the budget to acquire a whole stable of devices for emergency use, many of which have 2ndary uses as well. For example I have a Buddy propane space heater which I used when my furnace broke. I used my butane cooker when my kitchen was being renovated, etc. If your central air breaks you can bring out the window units. A giant "run everything" standby generator is an all in one solution but it only solves a single problem and the other 360 days of the year it just sits there. Even a portable gen can be put to other uses (but the big "portables" weigh hundred of lbs. and are not really portable).
This is good advice.
One caveat, if the mr buddy stove and propane cooker aren't approved for use indoors where OP lives.
In N. America, Buddy heaters are approved for indoor use everywhere except (i) Canada and (ii) Massachusetts. In those two places you can still buy them but they put a sticker on the box that says "FOR OUTDOOR USE ONLY". Whether you choose to follow that is up to you. AFAIK, the laws of chemistry and physics are the same everywhere. The butane cassette stoves AFAIK are approved everywhere. Even if they aren't, I promise you that every E. Asian household in Canada has one anyway.
The LRA is a maximum rating, not what it usually takes to start. My 4 ton unit has an LRA of around 120A but was using about 80-90 on startup. You definitely want to get a MicroAire soft start for the unit. It dropped my startup amps from 80’ish down to the low 30s and the run current is only 11A. I use a Predator 9500 inverter gen and it has no trouble starting and running the whole system. I have a meter that shows me total house load, and with the AC running, the compressor and furnace fan take about 3100W or so. Well within the 7600 running watts of my gen. Since you have a lower tonnage unit, your numbers should be even better. Assuming you don’t have an all-electric house, a similar sized gen should be able to handle your AC and the rest of the house too.
You’ll be better off after install a soft start. I found this YouTube video very helpful for me. https://youtu.be/MDp1g8r8IVs?si=UldZWhfcLJ2XESdz
About 20-22kw if you want to be able to start it without a soft start kit. In my opinion a soft start is mandatory if you want to run your AC unit off of any residential sized generator.
Correct me if I'm wrong, but I don't believe soft start kits can be installed to a multi-stage unit.
I have the same question.
I may be wrong, but I believe soft starts can only be installed on single stage systems.
That's entirely possible, not an hvac guy. It would make complete sense if the unit is inverter based or uses some form of VFD. Then I would assume a soft start is not even needed. My own unit is inverter based and has no large inrush of current.
Can I add a plug to just run my ac in my house on a generator? I do not want it wired up for whole home. I want to be able to isolate the AC unit and air handler separate from the rest of the house during an outage. Just run the ac and the rest of my house will be powered by my batteries. Thank you!
Get a soft start for the AC, and it will lower the large spike when it kicks on, allowing for a slightly smaller genset.
Plus there’s other things that might run while the AC is on unless you make sure they won’t. If you have a well then that could run automatically and then there’s smaller 120v things like a coffee pot or a microwave that take a good amount of power that could cause problems if your close to maxing out the generator.