# Finding power usage of fridge

Joined Jan 12, 2021
79
Hi folks. Hope all is well.
I am trying to buy a power generator to power my fridge etc in case of a power outage.

Before I do that, I need to first find how much watts my fridge needs to run on.
The fridge manual says that the fridge uses 531KWh per year. ( That is the only info that they provided )

I found that the fridge uses 1451.79 watts per day ( 531 KWh / 365 days).
Then I found that 1451.79 / 24 hours = 60.61 Watts

Is it okay to assume that the fridge uses on average 60.61 Watts of power every hour that it is connected to the power generator?

Thanks for the replies!

Last edited by a moderator:

#### AlbertHall

Joined Jun 4, 2014
12,293
The generator will need to provide the maximum power the fridge uses not the average power.
I would expect there to be a rating plate on the fridge that states the power it needs. See if you can find one - probably round the back.

Joined Jan 12, 2021
79
The generator will need to provide the maximum power the fridge uses not the average power.
I would expect there to be a rating plate on the fridge that states the power it needs. See if you can find one - probably round the back.
Ty. I will find it and reply here.

#### dl324

Joined Mar 30, 2015
16,203
Also note that gas generators will have a peak wattage rating that will be higher than the nominal wattage rating.

#### Ian0

Joined Aug 7, 2020
8,975
Why don’t you buy an ammonia-absorption refrigerator, and run it off LPG? Although ammonia absorption refrigerators aren’t the most efficient, the are rather better than the 20% or so you would achieve with a petrol generator.

Joined Jan 12, 2021
79
Why don’t you buy an ammonia-absorption refrigerator, and run it off LPG? Although ammonia absorption refrigerators aren’t the most efficient, the are rather better than the 20% or so you would achieve with a petrol generator.
Do u live in the US? Just asking cause your idea might not be feasible here in the US.

Joined Jan 15, 2015
7,256
OK, normally somewhere on the refrigerator, usually on the back, you should find a sata sheet. That tag should list the power requirements. This is a very good read on the subject. Keep in mind when refrigerators start they briefly draw power well in excess of their run power. Generators are often rated similar. Terms like Peak Power and Run power apply. You want the normal run power on a generator to exceed your demand by about 20%. Average numbers of watts per day, week, month or year are nice for helping figuring cost per year to operate are nice but not really useful for calculating a generator size.

<EDIT> You also need to consider generator type and the fuel type. The label in my fridge / freezer type calls out 6.5 FLA (Full Load Amps. It runs on 120 VAC 60 Hz. So that tells me 120 V * 6.5 Amps = 780 Watts. Really not much of a load. Allowing for some overhead a 1.0 KW generator should do fine with a peak allowance of maybe 2.0 KW. Peak demand on a refrigerator is very brief at start up. You will find 2.0 and 3.0 KW generators are not that expensive. Fuel can be gasoline, propane or even natural gas. Just remember using gasoline the fuel tank size. Remember also when not in use you want an empty fuel tank and carburetor. Fuel should be stored with a stabilizing agent and stored fuel replaced annually. Low power applications offer the choice of the newer "Inverter Type" generators. Once you figure out your power needs then start shopping. Consider also if you plan to run anything else like basic lighting during mains power outages. </EDIT>

Ron

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Joined Jan 12, 2021
79
OK, normally somewhere on the refrigerator, usually on the back, you should find a sata sheet. That tag should list the power requirements. This is a very good read on the subject. Keep in mind when refrigerators start they briefly draw power well in excess of their run power. Generators are often rated similar. Terms like Peak Power and Run power apply. You want the normal run power on a generator to exceed your demand by about 20%. Average numbers of watts per day, week, month or year are nice for helping figuring cost per year to operate are nice but not really useful for calculating a generator size.

<EDIT> You also need to consider generator type and the fuel type. The label in my fridge / freezer type calls out 6.5 FLA (Full Load Amps. It runs on 120 VAC 60 Hz. So that tells me 120 V * 6.5 Amps = 780 Watts. Really not much of a load. Allowing for some overhead a 1.0 KW generator should do fine with a peak allowance of maybe 2.0 KW. Peak demand on a refrigerator is very brief at start up. You will find 2.0 and 3.0 KW generators are not that expensive. Fuel can be gasoline, propane or even natural gas. Just remember using gasoline the fuel tank size. Remember also when not in use you want an empty fuel tank and carburetor. Fuel should be stored with a stabilizing agent and stored fuel replaced annually. Low power applications offer the choice of the newer "Inverter Type" generators. Once you figure out your power needs then start shopping. Consider also if you plan to run anything else like basic lighting during mains power outages. </EDIT>

Ron
Thank you very much for taking the time to write that all down.

The data plate on my appliance says:
Electrical Rating: 2 Amps Volts 115 V.

Joined Jan 15, 2015
7,256
Well alrighty. 2.0 Amps at 115 VAC is a very light load. You are only looking at about a 230 Watt load. I am guessing a small refrigerator. Possibly like those used by students in dormitories. I have one that is 115 Volt 1.0 Amp I use for beverages. It even has a tiny freezer. You are looking a very small portable generator. Brand names like Honda come to mind, while not inexpensive they are highly reliable. Here in the US there are also units from Harbor Freight which are very inexpensive but I can't attest to their reliability. All low power units like this are manual pull start and do not require much strength to pull start. Not knowing your budget I can't make a call but something like this little 2.0 HP gasoline unit would be way more than enough allowing for maybe some illumination. The

• 1500 starting watts and 900 running watts
is a good reference to what I mentioned earlier. It will handle a 1500 watt peak and provide 900 continuous watts. Moderate load you get 8 hours on a gallon of gasoline. Not bad at all. Figure a 5 gallon can of gas buys you over 40 hours of run time. During a mains power loss you just run enough to make cold, then shut down and make cold as needed.

There are other options to run a fridge like inverters powered off batteries but when the batteries die?

Ron

#### Ian0

Joined Aug 7, 2020
8,975
Do u live in the US? Just asking cause your idea might not be feasible here in the US.
Ammonia is an approved refrigerant in USA. It is known as R717, and has zero global warming potential and zero ozone depletion potential, so, in that respect is one of the best refrigerants around.
https://www.dometic.com/en-us/outdoor/food-and-beverage/refrigerators/rv-refrigerators
My little caravan fridge runs for 10 days on a 6kg bottle of butane, even if I take it somewhere rather warm like the south of France.
(No, I don't live in the USA)
As ammonia fridges don't have compressors, they are completely silent.

#### shortbus

Joined Sep 30, 2009
10,039
Do u live in the US? Just asking cause your idea might not be feasible here in the US.
I take it you don't live near any of the Amish communities. There are quite a few in my area and they all use propane refrigerators and freezers. Most but from these folks that supply many "off grid" items most of us assume to only be electric. https://www.lehmans.com/category/gas-refrigerators-freezers

Joined Jan 15, 2015
7,256
Ammonia is an approved refrigerant in USA. It is known as R717, and has zero global warming potential and zero ozone depletion potential, so, in that respect is one of the best refrigerants around.
https://www.dometic.com/en-us/outdoor/food-and-beverage/refrigerators/rv-refrigerators
My little caravan fridge runs for 10 days on a 6kg bottle of butane, even if I take it somewhere rather warm like the south of France.
(No, I don't live in the USA)
As ammonia fridges don't have compressors, they are completely silent.
My friends RV here in the US had one of those. It worked very well. Wasn't very large but very efficient. Since the thread starter mentioned power I just assumed this was a standard AC mains powered fridge. Turns out it is a small unit. Anyway, I agree as to your suggestion had the thread starter not already had a unit. Anyway ammonia absorption is something that has been around a long time for good reason. It works and works well. I have no clue what a 4.0 or 5.0 cubic foot small unit sells for? There is really not much that can go wrong with those units.

Ron

#### Ian0

Joined Aug 7, 2020
8,975
There is really not much that can go wrong with those units.
The one in our caravan is now 42 years old. It's had a new gas jet and a new door seal, and I think the problem was the door-seal and not the gas jet.

Joined Jan 15, 2015
7,256
The one in our caravan is now 42 years old. It's had a new gas jet and a new door seal, and I think the problem was the door-seal and not the gas jet.
When we looked at my friend's unit it was amazing the simplicity. I told him that fridge would well outlive the RV and it did. I think the idea predates freon and compressors back to the 1800s or so but I think they became commercially available maybe 1920s? There was one in my grandparents brownstone house in Brooklyn NY which was replaced with a compressor fridge when Consolidated Edison made electricity available to the Park Slope section of Brooklyn, NY. I discovered it in a cellar and that is the only reason I knew of its existence. Pure genius.

Ron

#### bassbindevil

Joined Jan 23, 2014
798
The easiest is to just get a gadget that measures power consumption, like the P3 Kill-A-Watt or one of the numerous no-name copies. The actual power consumption will vary depending on room temperature and how often the fridge is opened. 60 watts average sounds plausible; my ancient bar fridge used about 85 watts (measured with the Kill-A-Watt) when it was running, but average would have been much less.
If you have a separate chest freezer, those stay cold for a long time without power, so you could just run the generator once a day. Keep some blocks of ice in there, and use them to keep the essentials cool in a couple of picnic coolers. Or hook an inverter to your car battery, and keep the engine running while you "charge up" the freezer for an hour. Having an inverter as back-up would be sensible since small gasoline engines can be troublesome. It's also a step towards off-grid solar power. Consider whether getting a couple of solar panels and a battery could supply enough juice to run the fridge and essentials.
These decisions really depend on your situation; in my part of the world, lengthy power failures only happen about every 10 years, and in the dead of winter, when there is free refrigeration outside the back door, and the house gets cold enough that the freezer is OK for days without power. But maybe owning a generator would also come in useful for work or recreation.

Joined Jan 15, 2015
7,256
These decisions really depend on your situation; in my part of the world, lengthy power failures only happen about every 10 years, and in the dead of winter, when there is free refrigeration outside the back door, and the house gets cold enough that the freezer is OK for days without power. But maybe owning a generator would also come in useful for work or recreation.
So in your part of the world when the lights go out in the dead of winter and the house gets cold, real cold real fast how do you stay warm in a freezing cold house? Around here in NE Ohio, USA it is not long before pipes start bursting. I really dislike dark and cold and the older I get the more I dislike it. My solution was simple. A whole house generator with automatic transfer running on natural gas with a propane backup. That failing a 4.0 KW gasoline powered generator. I really hate cold and bursting pipes. I place a value on creature comfort.

About now I have refrigeration outside the back door but at about 25 F not enough to sustain my frozen meats in the freezer.

Ron

#### crutschow

Joined Mar 14, 2008
33,369
2.0 Amps at 115 VAC is a very light load. You are only looking at about a 230 Watt load. I am guessing a small refrigerator. Possibly like those used by students in dormitories.
Not necessarily.
I just bought a new Galanz retro-style, frost-free 12 cu. ft. refrigerator/freezer for the basement media room, and it's rated to use only 1.2A @ 115V (138VA) and 312 kWH/year.
They seem to be making refrigerators pretty efficient these days.

#### debe

Joined Sep 21, 2010
1,388
(2) Electricity backup DIY solution | Page 2 | All About Circuits Check this thread out for a cheap way to run a fridge. Inverter fridges dont have a large start current, also use verry little power. Also cheaper than 3way Ammonia fridges. 600w will run my fridge TV & lights when the power goes out (lights are all LED) Also do not use the 2stroke generator previously mentioned as there voltage stability is atrosious. I have one but dont use it any more as the voltage can go quite high with unstable engine RPM. Replaced it with an inverter 4stroke generator.

#### Ian0

Joined Aug 7, 2020
8,975
Back to the original question, and maybe stating the bleedin’ obvious, the rated annual energy consumption will be at some standard temperature, whereas the actual energy consumption will be proportional to the difference between fridge temperature and ambient; and to how long the door is open, and how often you put a big bowl of still-hot food into it.