refrigerator. Gas vs electric.

[garbonz]

Ok, for you geniouses out there

91333 BTU per gallon of propane
3412 BTU per KWH of electricity.

Spot price for propane is $2.50 per gallon.

So based on the above and assuming equivalent efficiency for each heating method in the ammonia frig then. Drum rolllllllllll.

.0934$ per KWh is the break even point given 2.50$ propane.

[garbonz]

And the reason why your run of the mil rv frig runs and cools bettter on propane is that the propane burner has more BTU's than the electric burner

Example: AMERICANA DOUBLE DOOR DM 2852

Propane rating 1501 BTU/hr
Electric rating 325 watts or 1108 BTU/hr

[gwaltneyra]

Best to experiment. One week on propane, one week on electric. Keep a thermometer in both the fridge and freezer and you'll know the delta.

[cavie]

Originally Posted by gwaltneyra

Best to experiment. One week on propane, one week on electric. Keep a thermometer in both the fridge and freezer and you'll know the delta.

Yep,intend to do that when we get back but will test for 1 month. It won't be exact do to the weather and if we use heat or A/C but I'll get a good idea.

[rockfordroo]

The fridge will cool faster on gas because gas can put out more BTU's/hr, increasing the cooling efficiency over the lower BTU/hr electric.

BUT - Once it's been cooled down and the only cooling needed is to account for heat loss through the fridges insulation and occasional door opening, the fridge should use the same number of BTU's on electric as on gas. It will only use what it needs.

So as suggested above, get a watt-hour meter and put it on the fridges 110VAC plug. Then run it on electric for a week and see how many watt-hrs it uses. Then run it on gas for a week and see how much gas you use. You'll then have your answer.

[mwdilday]

Originally Posted by youroo

The answer is Yes! We leave ours set on "Auto" going down the road is just as Cold as shore power! Youroo!! PS Ice cream is Always HARD,and Milk is always COLD!

X4 we have the 4 door Dometic and it works great.

[kayo]

RV refrigerators are what is known as absorption refrigeration, requiring Heat, either created by an electric heating element or a propane burner. there is no motor or compressor. it is strictly the heat

[davel1971]

The amp draw when on electric is very low, as there is no moving parts. I would use the electric and save the propane as a backup. You don't have to refill the electric.

[johnbryanpeters]

Originally Posted by rockfordroo

The fridge will cool faster on gas because gas can put out more BTU's/hr, increasing the cooling efficiency over the lower BTU/hr electric.

BUT - Once it's been cooled down and the only cooling needed is to account for heat loss through the fridges insulation and occasional door opening, the fridge should use the same number of BTU's on electric as on gas. It will only use what it needs.

So as suggested above, get a watt-hour meter and put it on the fridges 110VAC plug. Then run it on electric for a week and see how many watt-hrs it uses. Then run it on gas for a week and see how much gas you use. You'll then have your answer.

That presumes constant external temperature...

[garbonz]

Originally Posted by davel1971

The amp draw when on electric is very low, as there is no moving parts. I would use the electric and save the propane as a backup. You don't have to refill the electric.

OP post was about what was cheaper, amp draw is irrelevant. Example above is 325 watts or 3ish amps, or 3 100 watt light bulbs. Propane is 1105 BTU or 0.012 gallons per hour, or 354 hours of constant operation or 14 days on a 20 lb tank. Frigerators don't run constantly, so more like a month at a 50% run cycle.

Propane s WAY chaeaper at the 0.24/kw price point, so may be worth filling a 20 lb tank once a month or so.

[davel1971]

Originally Posted by garbonz

OP post was about what was cheaper, amp draw is irrelevant. Example above is 325 watts or 3ish amps, or 3 100 watt light bulbs. Propane is 1105 BTU or 0.012 gallons per hour, or 354 hours of constant operation or 14 days on a 20 lb tank. Frigerators don't run constantly, so more like a month at a 50% run cycle.

Propane s WAY chaeaper at the 0.24/kw price point, so may be worth filling a 20 lb tank once a month or so.

Amp draw is just as relevant as the price per unit. You can't calculate cost without knowing power usage. The run time depends on outside temp, so it very well could run 100% of the time.

[rockfordroo]

Originally Posted by rockfordroo

The fridge will cool faster on gas because gas can put out more BTU's/hr, increasing the cooling efficiency over the lower BTU/hr electric.

BUT - Once it's been cooled down and the only cooling needed is to account for heat loss through the fridges insulation and occasional door opening, the fridge should use the same number of BTU's on electric as on gas. It will only use what it needs.

So as suggested above, get a watt-hour meter and put it on the fridges 110VAC plug. Then run it on electric for a week and see how many watt-hrs it uses. Then run it on gas for a week and see how much gas you use. You'll then have your answer.

Originally Posted by johnbryanpeters

That presumes constant external temperature...

Of course. It also assumes you open the door about the same number of times and you load in about the same amount of food. Lots of variables. But it's the only way you'll truly be able to get an idea of which is cheaper.

[rracer5]

Originally Posted by cavie

Answer: Taxachusetts and it is commercial rate not residential. The park is a business.

Same in SC (Myrtle Beach). Santee Cooper Electric charges the park 12.3 cents per Kwh. I think residential customers pay between .03 & .06 cents depending on their usage plan. But, they add "other" charges (ie; fuel surcharges, meter reading fee & a flat $25 administrative fee etc.).

[kayo]

Re the relative amperage, it takes far ,ore amps to generate heat than it does to run a motor or compressor

[davel1971]

Originally Posted by kayo

Re the relative amperage, it takes far ,ore amps to generate heat than it does to run a motor or compressor

my Dometic is 8 cu ft and when on electric it draws only 2.7 amps. I'm sure a residential fridge is more than that.

[carlsbad]

We RV people are funny. We spend $$$$ on rigs and then debate how to save a few bucks on energy. Use whatever is convenient.

[FFred]

"You don't have to refill the electric."

True enough but the propane does require cleaning of the chimney at times.

No buildup with electric.

[cavie]

Originally Posted by garbonz

OP post was about what was cheaper, amp draw is irrelevant. Example above is 325 watts or 3ish amps, or 3 100 watt light bulbs. Propane is 1105 BTU or 0.012 gallons per hour, or 354 hours of constant operation or 14 days on a 20 lb tank. Frigerators don't run constantly, so more like a month at a 50% run cycle.

Propane s WAY chaeaper at the 0.24/kw price point, so may be worth filling a 20 lb tank once a month or so.

5er has 2- 30lb bottles. We go to town often so no problem.

[cavie]

Originally Posted by carlsbad

We RV people are funny. We spend $$$$ on rigs and then debate how to save a few bucks on energy. Use whatever is convenient.

It's because we spent $$$$$$ on the rig we learn to live on an unfixed income adjusted down by government stealing from SS and raising taxes and having to save a few bucks all the time.

[carlsbad]

At 500kw per year for a residential fridge, the monthly cost at $0.24kw is $10.00. Use propane and pay about $8.50 a month. Spend the extra $1.50 wisely.