How often does a Fridge Cycle

[mobiledynamics]

Running off a deadline so I'm up early and with no ambient noise in the house...I can hear the fridge running every 30 min or so. Granted modern fridges cools and defrosts.....

Just wondering for those that have monitored your electrical usage, how often does a typical fridge cycle on / off , relative to also cooling *less juice* versus defrost cycles..

 

[Teken]

Its funny you have asked because I have been monitoring my appliances for about 7 months now. One of the items I wanted to know was the fridge and how setting the TSTAT in the unit would affect the on / off time.

Below are some stats and I will explain what I saw and observed to be the most ideal for me.

This is a bulk review: The average load is aprox 40 watts.

This is a median review:

This is a fine review: The fridge started at 2:26 AM, initial turn on power was 133 watts. As the fridge comes to normal operation its runs a steady 114 watts, which lasts for 33 minutes. This cycle happens aprox every 62 minutes at the setting of 3.0 on the fridge TSTAT.

This is the fridge set to 3.5 on the TSTAT. The fridge starts at: 7.07 AM.

The fridge stops cooling at: 7:37 AM, so it ran for 30 minutes. Which is 3 minutes more than the 3.5 setting.

This shows the spread in duration of the fridge coming on which starts at 7:36 AM.

The next cooling cycle doesn't start until 9:01 AM

So you can see setting the fridge to a higher settings will decrease the amount of run time your appliance will run, and consume energy. In this case it runs every 1:25 minutes.

My ultimate goal was to get my fridge to be with in 33-40'F. This is considered the safe zone for the fridge. Having your fridge set to 30'F will consume a lot more energy and will not make anything last any longer. It will also make things teeter on freezing for some items.

This time last year I asked a really odd question. I had asked if anyone had considered taking those mini cooler freezer blocks to use to *fool* and keep the freezer / fridge at a stable temp.

Most of the folks thought it was a waste of time. In reality it proved be very effective on two fronts.

These are basics I was never really aware of:

1. Keep the fridge / freezer full. The items in those compartments will store & emit their energy as the door is open. Which will than make the fridge run less.

A empty fridge will lose its ambient temp right away and the fridge will have to run the entire cycle to just to meet the programmed temp.

2. Having the freezer blocks will ensure if the device should fail. This will provide you a few extra hours of cooling / freezing.

3. Always install a calibrated thermometer to confirm fridge / freezer temps. This will alert you of potential hardware issues, and spoilage.

My plan this summer is to hook up my sensors to the fridge / freezer to be alerted of a fault or out of spec temp setting.

Doing this one small project has saved me several dollars per month on my electrical bill. It was also a proof of concept to have facts of how a setting can impact the actual appliance. Lots of folks can guess, but few have the facts to back up their claims.

I rather use imperial facts to make my position and then make a educated decision on the best course of action.

Teken . . .

 

[Teken]

I wanted to clarify another reason I use the freezer pack bricks. I have a small family and we don't normally have a full fridge of food on hand. Our lifestyle is very busy and it tends to go to waste because we are not home for long periods of time.

So, to ensure the fridge stayed at a predictable *FULL* state. I have a about 5-6 freezer packs placed in the fridge / freezer compartment. This ensures a *static* volume of cooled / frozen items in the appliance.

This has made the fridge run less.

Teken . . .

 

[CNGsaves]

Wow Teken . . . you're the defacto guru on frig energy use!!

Got another test for you to try some time:
. . . . rotate some of the frozen packs from the freezer into the frig and see if they reduce the overall energy use

I too keep lots of "frozen mass" in the freezer compartment to help the frig run easier - - - and also serve as failsafe if lose electricity. Mine are just 1 ltr water bottles about 2/3 full. They work great for taking to sporting events as just top off with water and have melting cool water for hours.

My grandma would keep lots of extra frozen 1 gal jugs of water in chest type deep freeze when it wasn't full of 1/2 sides of beef.

Just curious if idea can be taken further and put a frozen jug in the frig.

 

[Teken]

Wow Teken . . . you're the defacto guru on frig energy use!!

Got another test for you to try some time:
. . . . rotate some of the frozen packs from the freezer into the frig and see if they reduce the overall energy use

I too keep lots of "frozen mass" in the freezer compartment to help the frig run easier - - - and also serve as failsafe if lose electricity. Mine are just 1 ltr water bottles about 2/3 full. They work great for taking to sporting events as just top off with water and have melting cool water for hours.

My grandma would keep lots of extra frozen 1 gal jugs of water in chest type deep freeze when it wasn't full of 1/2 sides of beef.

Just curious if idea can be taken further and put a frozen jug in the frig.

I actually did that last year but the test was not very accurate due to the fact *We as a family* was in and out of the fridge. The fridge was also not at a static state for very long.

So, I couldn't really count on the measurements being accurate. Nothing gets my goat than guessing!

This time this month I will perform the same test again. I am not sure what will come out of it to be honest. But, probably predict it will have very little impact to the cycling.

I too am also going to be freezing water bottles. As the summer approaches its a great method to have something on hand as dual use. Have it in the coolers as a ice pack. Once it melts its still a great form of chilled water when needed.

I am currently saving up for a upright freezer for the home. I plan on doing what you have and storing bottles of water to ensure a stable and static volume in the freezer.

I am currently testing my hot water tank. I will publish my findings in another thread so others can follow. Of the appliances that run 24/7/365. These two items have the most impact on the electrical bill during the summer time.

Teken . . .

 

[tylernt]

I am currently testing my hot water tank. I will publish my findings in another thread so others can follow. Of the appliances that run 24/7/365. These two items have the most impact on the electrical bill during the summer time.

Well... except maybe the air conditioner.

 

[Teken]

Well... except maybe the air conditioner.

True, but I don't have one. So, no impact on me there! Now, if we're taking about winter then the furnace is the next big hitter!

Teken . . .

 

[Highbeam]

Or hot tub.

 

[mobiledynamics]

Hmm...I find the power draw interesting....notheleast.
Aside from intitial plug in, by which it should default to a high power draw, I'm not seeing any major difference in the *low power draw* when in a cooling or a defrost cycle.

 

[pattenp]

A lot if you have kids. That inside light creates a lot of heat when they stand there with the door open trying to figure out what they want.

 

[Teken]

Or hot tub.

I'm too poor to own one.

Teken . . .

 

[Teken]

Hmm...I find the power draw interesting....notheleast.
Aside from intitial plug in, by which it should default to a high power draw, I'm not seeing any major difference in the *low power draw* when in a cooling or a defrost cycle.

I don't follow?

Teken . . .

 

[mobiledynamics]

The fridge has 3 cycles the way I look at it.
I've yet to test, but when unplugged, and if you plug it back in, I would think it would automatically do a *high draw* and cool to temp. Even if it had lost power - aka, initial surge/power draw.

The fridge not only does cooling, but it also defrost *assuming you have a freezer that defrosts* and you don't manually do it. I was under the impression/understanding that when it does the defrosting...it draws much more juice than just cooling. I can't recall the specifics, but did reference this detail in a couple of places when I did homework on sizing up generator power usage..

 

[RECox286]

Lots of variables come into play to answer your question.

You have to realize that the machine is trying to cool, while the

ambient outside temperature is trying to heat. The difference is

how well the insulation package is and how good the door seals

are. (obviously) The less efficient the above two factors are, the

more the compressor will have to cycle for any given setting, and

the delta T between what the controls are set for and the ambient

temperature. That is the basics of the beast. So, what style, and

how old is the box ? (1, 2or 3 door, hole in the door for ice/water)

(1930,40,50,60,70,80,90,2000,10) Where is the box located ? (Fla, Aka)

(in the house/in an unheated garage or shed )

Once these perimeters are known, then you can start with the data

tables. Trust me, once you know the truth about how much it costs

to keep a refrig/freezer running (after the initial purchase price) you

will probably want to cool your beer in the creek !

Uncle Bob

 

[Teken]

The fridge has 3 cycles the way I look at it.
I've yet to test, but when unplugged, and if you plug it back in, I would think it would automatically do a *high draw* and cool to temp. Even if it had lost power - aka, initial surge/power draw.

The fridge not only does cooling, but it also defrost *assuming you have a freezer that defrosts* and you don't manually do it. I was under the impression/understanding that when it does the defrosting...it draws much more juice than just cooling. I can't recall the specifics, but did reference this detail in a couple of places when I did homework on sizing up generator power usage..

Understood, thank you. Speaking for myself, the fridge I have goes into defrost mode every couple of days. It spikes to 472.33 watts for about 5-10 minutes I believe.

I will have to look at the logs to confirm.

But, yes when it kicks in its literally 4 times the power draw.

As pattenp noted, if you have kids and they are in and out of the fridge. I don't care what you do. That fridge will run on forever!

This spike is my little one poking her head in the fridge.

Teken . . .

 

[Milton Shaw]

Most refigs are designed to run 50% of the time with no door openings and no icemaker operation. Older refigs had electric strip heaters around freezer opening seal area and dispenser area. Newer refigs have hot loops off the freon system to provide most of that heat, (feature called automatic energy savings on older GE). The moisture switch turned that electric heater on or off. The defrost cycle is the most expensive time the refig runs as it has large electric heater running and then compressor has to run extra time to get unit back cold. Ice makers as they cycle have large heater to release the ice and let it fall in the bucket. That's a big energy usage also. If icemaker stalls in heat cycle I have seen plastic parts in freezer melted from this, as normally that heater is only on a minute or two. The calrod heater in icemakers will burn you if you happen to touch the bottom of icemaker mold when its in defrost cycle. Most of the newer GE refigerators use less than a 70 watt light bulb over the course of a week. Refigs are designed to run 50% of the time in 70 degree room temp to keep frozen stuff frozen and refig at right temp.

 

[Highbeam]

Pretty amazing that the fridge uses so little power overall but also the max load is 500 watts. You could run a lot fridges with a small generator in a power outage.

I wonder how a typical garage freezer would compare.

 

[mobiledynamics]

Hey Teken ---

If you plan to do some more testing, I'd be curious on what the startip=inrush current is. A wild guess will be around 1100-1200 but one can only speculate.

Your #'s looked about right in my head. I had around 150-200 on cooling, and a wild # of 400-500 on defrost.

 

[Teken]

Hey Teken ---

If you plan to do some more testing, I'd be curious on what the startip=inrush current is. A wild guess will be around 1100-1200 but one can only speculate.

Your #'s looked about right in my head. I had around 150-200 on cooling, and a wild # of 400-500 on defrost.

I will need to report back much later on the *In rush current* as the maker of the energy monitoring device is still developing this aspect. Once its fully deployed I will surely reply back as to what it is.

Having the ability to measure and know the exact in rush current / start up load will play a big role in my solar back up system. Right now I am simply guessing and converting the watts into the current values I see.

I would rather see the actual current / amps. Right now I am over sizing all the wires, inverters, batteries, etc to ensure all high current loads can be used and powered with out voltage drops.

This costs way more, therefor you can see why I want to know exactly what it does draw. I do have a clamp on meter but that isn't something you want to use or can use for a long period of time.

It also can't tell you if something is wrong at any given moment. Hence why I have my GEM / DB / ISY to notifier me of impending faults.

Teken . . .

 

[ezzzzzzz]

My ex did it once a month.

 

[Teken]

This is what happens when you don't let things cool before placing the items in the fridge. This is also the net results of having people in and out of the fridge during an entertaining event.

Short version:

- Lots of folks over for Mothers Day.

- People in and out all day.

- Tons of left overs but nobody thought it would be a good idea to let it cool first!

- Fridge starts to cool at 1:30 PM consuming aprox 109 watts.
- Defrost kicks in at 4:49 to 5:17 PM consuming aprox 490 watts
- Continues to run until 7:49 PM.
- 6.50 hours later its finally cool.

Teken . . .

 

[Highbeam]

6.5 hours at 100 watts would only cost me 65 cents. These things are cheap to run.

 

[bseant]

got a question on this. i need to replace a freezer for my parents, right now they have whirlpool upright freezer from the 70's bout 17cu or so. How would one compare this freezer to just a modern freezer and a modern energy star freezer? i know it's big but does anybody have any numbers? thanks.

 

[Teken]

got a question on this. i need to replace a freezer for my parents, right now they have whirlpool upright freezer from the 70's bout 17cu or so. How would one compare this freezer to just a modern freezer and a modern energy star freezer? i know it's big but does anybody have any numbers? thanks.

I'm not sure how you would compare the old freezer with out something like a *Kill A Watt* meter, or what I use.

Go on line and purchase a $25.** Kill A Watt meter and plug it in and measure how much money it costs to run this old freezer. Then, go to any store you're considering and compare it to the Energy Star label attached to the appliance.

Ensure you calculate the costs based on your regions electrical dollar / cents. Most of them are based on $0.11 and that might be too high / low. So break out the calculator and add it up.

I would be very surprised if your parents old 1970 freezer beat out a newer style freezer in terms of costs per use. But, another factor would be long term life and reliability.

I think your parents freezer has proven hands down they don't make them like they used to! I challenge anyone to show me something they bought in 2000 ish that still operates. Most of the stuff is built to last 3-5 years and turn into dust.

Please follow up as I would be very curious how much that unit costs your parents.

Teken . . .

 

[mobiledynamics]

Paging Teken -

Just came across this today and thought of you !

http://www.theenergydetective.com

 

[Teken]

Paging Teken -

Just came across this today and thought of you !

http://www.theenergydetective.com

Yes the TED was probably one of the first and best well known energy monitors out there. I had looked into this brand more than 5 years ago. But, after reading the documents and talking to various forum members. It was determined there would be power line communication errors from this device to my Insteon network.

I believe the TED is a great solution for those on a budget or simply wants a general idea of where the energy is going. The UI is pretty slick and the easy to read and use.

My personal needs were much higher so I decided to purchase something more commercial and that had development support. The GEM (Green Eye Monitor) that I use is both commercial / consumer based.

Features and development continues to be made and added. The TED is not supported in the same fashion and third party plugin's along with a open API are not freely available for the general public.

Teken . . .

 

[VHF]

6.5 hours at 100 watts would only cost me 65 cents. These things are cheap to run.

I think you mean 6.5 cents, assuming you are paying $0.10/KWH. Now that is cheap. At a 50% duty cycle, we're looking at $3.60/month or $43/year, which is what is expected for a modern medium size EnergyStar fridge.

New fridges have a lot more insulation, which generally means thicker walls than older fridges. One problem is when putting a new fridge in an older house it may not fit, or may stick out into the traffic area too much because the new fridge is bigger on the outside.

My first house came with a 1974-vintage avacodo green Kenmore. I borrowed a Kill-A-Watt meter from the library (now I own one) to see what the power consumption was. I figure it cost me $85/year to run that fridge, which wasn't as bad as I thought. Some older fridges cost over $120/year to operate.