There are a lot of complicated scenarios here. IMHO, there are two scenarios to be considered.

One, keeping the fridge plugged in. I’d take periodic measurements, over a long period of time, of the power used when plugged in. Calculate the average power cost per hour of continuous operation. E.g. cost of keeping it plugged in.

Secondly, with the fridge off for an extended period of time, I would fill it as if for a party, turn it on and measure power consumed over the time period it takes to cool the contents. Save this value and continue to measure power consumption for an extended period of time (several days) to measure the stable cooling power requirements. Add these two values together. This is the cost of intermittent usage.

Compare the two costs. Make your decision.

 

No need to figure all this beforehand. Just try unplugging it, and check periodically to see what happens. Let the fridge get to ambient temperature before opening the door, as condensation happens when hot, humid air hits cold surfaces.

 

- the question is how much more money does it cost, to go from room temp to operating temp vs. maintaining the operating fridge temp. [This is a standard half freezer/half fridge we are talking about made in circa 2004.]]

The way to guesstimate this is to pack the fridge with all your drinks , switch on , and see how many hours it takes to reach fully cold inside...

I would imagine 12 hrs is plenty ... and the compressor would have been working fully for that time ...

Once it's cold inside the thermostat will maintain that temp by switching the compressor on and off ... if doors remain closed probably the compressor is on for only a 1/3 rd of the time ...

So lets say you have a party every three weeks

Option one , the fridge is on all the time ... it will still have to work harder when you re-stock with room temperature drinks , so power used is 12 hrs for initial cooling + 3 weeks at 1/3 power
That's 1week and 12hrs of full power consumption

Option two , you stock the fridge and turn on 12 hrs before party .... That's only 12 hrs of full power consumption

Also you save wear and tear on the fridge compressor .

Mold is only an issue where open food is stored .

De frosting is not needed since it's only on for 12 hrs.

 

This guy ↓ for President and thank you all for posting.

You have tiered billing where the first 600 kWh of electricity you use is charged at a little over 10 cents/kWh, the next 400 kWh are billed at a little over 6 cents/kWh, and everything about 1000 kWh is billed at just under 5 cents/kWh. In addition to this "commodity charge" you are charge three specific taxes/fees/surcharges (or whatever name they choose to call it) that total about 0.77 cents/kWh, though this appears to vary a bit month to month, probably in part to adjust for spot changes in the cost of fuel or energy purchased. This is charged on every kWh from the first to the last. If you have a partial month, the tiers are prorated based on a 30-day month.

Since it appears you are always above 1000 kWh/mo, running or not running the fridge will only affect the usage that gets billed that final tier, so we are talking about a total of about 5.76 cents/kWh. Since it appears that your fridge is pretty consistent at about 70 W average draw, that means that it is costing you about 9.7 cents a day to run the fridge.

 

What ever happened to a cooler or even a bin with ice for a party? That's what we hillbilly's do out here in the sticks.

 

Mold is only an issue where open food is stored

Guess you never worked in a store refrigerator section.

 

A detail that nobody considers : a refrigerator is a heat pump.
In winter, the refrigerator contributes to warm the dwelling. All energy from the unit is dumped to the living area. All that energy is saved from the heating system. Leave it on, costs zero to operate.
In summer, the heat released by the refrigerator makes the air conditioning work extra as it has to pump its heat outside. Leave it off, as doubles its Kilowatts consumption to your bill.
If needed to be pickier, use the refrigerator indoors in winter and place it outdoors in summer. Will beat all measurements of energy consumed, and may coincide with the location of the crowd.

 

You ask what number you should put in your Kil-A-Watt. Here's how to calculate:

First off, your rates are interpeted like this: The FIRST 600 kWH usage FOR THE WHOLE MONTH costs $0.10625 per kWH. The next 400 kWH usage costs $0.06035 per kWH. All other usage beyond 1000 kWh for the month costs $0.04991. Now find your AVERAGE MONTHLY usage for an entire year (or whatever period your "party" season lies in). Let's say that your average monthly usage for an entire year is 2500 kWH. This would cost you:
600 x 0.10625 + 400 x 0.06035 + 1500 x 0.04991, or $162 for your BASE power (not including your additional fees that are tacked in on your power bill - you can add them in if you desire). So your average cost per kWH is 162/2500, or ~ $0.065 per kWH. So plug in the 0.065 into your meter.

Just remember that these numbers are AVERAGE based on an entire year of service. Like all averages, they will change if your power usage changes

 

Using AVERAGE cost is one way to estimating the cost of running the fridge.

Would it not make more sense to use the marginal rate of $0.05 per kWh?

The rationale for this is that running the fridge is non-essential usage. If you would normally be consuming more that the sum of the first two baselines of 600 kWh and 400 kWh, then the cost of running the fridge is an incremental charge on top of what you are already paying. @WBahn already pointed this out in post #9.

 

Using AVERAGE cost is one way to estimating the cost of running the fridge.

Would it not make more sense to use the marginal rate of $0.05 per kWh?

The rationale for this is that running the fridge is non-essential usage. If you would normally be consuming more that the sum of the first two baselines of 600 kWh and 400 kWh, then the cost of running the fridge is an incremental charge on top of what you are already paying. @WBahn already pointed this out in post #9.

Yeah, you can make that case. too. If the TS's average monthly electric usage is 6,000 kWH WITHOUT the fridge plugged in, then any incremental usage will only cost ~$0.05 per additional kWH.

 

Yeah, you can make that case. too. If the TS's average monthly electric usage is 6,000 kWH WITHOUT the fridge plugged in, then any incremental usage will only cost ~$0.05 per additional kWH.

From what I read in the posts TS has to use above 1000 kWh.

 

From what I read in the posts TS has to use above 1000 kWh.

He posted two bills where the average is 5,500 kWH per month. It's impossible to accurately extrapolate any useful average, but we do it anyway with the limited information we are provided.