refrigerator. Gas vs electric.

[davel1971]

Originally Posted by 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.

this topic really is that petty. We all could much easily find a way to save money over which fuel source to run the fridge on. Not worth racking your brain over a buck fiddy.

[cavie]

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

As a 45 year Licensed Master Electrician I am pretty sure AMPS has nothing to do with this post. The post is about BTU expelled by Gas vs Electric and the cost of each. From the most of the answers, I have decided that in my case @ $.24 kWh cost of electric that gas is the way to go. The answer of which will freeze and be cold has been answered as equal. So gas it is. I wish to thank everyone for participating and offering up your opinion. Some very good. Some not so much as in all forums I partake in. Thaks again. I'm done with this thread. Happy New Year.

[carlsbad]

Originally Posted by cavie

As a 45 year Licensed Master Electrician I am pretty sure AMPS has nothing to do with this post. The post is about BTU expelled by Gas vs Electric and the cost of each. From the most of the answers, I have decided that in my case @ $.24 kWh cost of electric that gas is the way to go. The answer of which will freeze and be cold has been answered as equal. So gas it is. I wish to thank everyone for participating and offering up your opinion. Some very good. Some not so much as in all forums I partake in. Thaks again. I'm done with this thread. Happy New Year.

Happy New Year. This forum is a wealth of information.

If you are just running a fridge and lights you might consider solar. In some cases you can apply for solar tax credits which can lower the payback to a couple of years. Have a good year and happy travels.

[pbryan]

One thing is missing in these calculations... efficiency. The BTU comparison assumes 100% of the energy is being used. To really compare the costs you have to know the refrigerator's efficiency on each fuel. If it cools using the same amount of energy from each source your numbers are good. But chances are one is more efficient than the other.

If, for example the fridge is 50% efficient on propane and 100% efficient on electricity, you'd need twice the BTU's of propane, for the same amount of cooling... I doubt the difference is that dramatic, but I suspect there is a difference.

Usually using a flame to heat something isn't great, there are losses in imperfect combustion and lots of heat simply goes up the chimney, but given the way adsorption fridges work, I'm not sure if the heat from the electrical element is more efficiently used or not...

Really hard to measure the difference too. You'd have to be able to accurately measure the consumption of both fuels over identical operating conditions...

[cavie]

Originally Posted by pbryan

One thing is missing in these calculations... efficiency. The BTU comparison assumes 100% of the energy is being used. To really compare the costs you have to know the refrigerator's efficiency on each fuel. If it cools using the same amount of energy from each source your numbers are good. But chances are one is more efficient than the other.

If, for example the fridge is 50% efficient on propane and 100% efficient on electricity, you'd need twice the BTU's of propane, for the same amount of cooling... I doubt the difference is that dramatic, but I suspect there is a difference.

Usually using a flame to heat something isn't great, there are losses in imperfect combustion and lots of heat simply goes up the chimney, but given the way adsorption fridges work, I'm not sure if the heat from the electrical element is more efficiently used or not...

Really hard to measure the difference too. You'd have to be able to accurately measure the consumption of both fuels over identical operating conditions...

You are the first person in 5 pages that understands what's going on. You are 100% correct about efficiency. I was hoping someone was gonna jump in here with that part of the equation. Even without knowing the eff. @$.24 kWH of electric is a no brainer. Gas wins.

[cavie]

Originally Posted by 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

that's what I'm talkin' 'bout!

[mwdilday]

Who cares about efficiency. Either way you are spending peanuts.

[pbryan]

Originally Posted by mwdilday

Who cares about efficiency. Either way you are spending peanuts.

If you really care about the energy use of your fridge, you would dump the 2-way adsorption fridge and install a residential compressor fridge. For a similar size they can use as little as 10-20% of the electricity of a 2-way in AC mode.

[mwdilday]

Not sure if that is accurate or not and since I am always on campground power I am not too concerned about it. I like the looks, installation and propane option of the gas/electric fridge. The residential installations are crap and they look like they belong in a house, not an RV. The ice maker is a maintenance issue when winterizing. Too many downsides.

[cavie]

Originally Posted by pbryan

If you really care about the energy use of your fridge, you would dump the 2-way adsorption fridge and install a residential compressor fridge. For a similar size they can use as little as 10-20% of the electricity of a 2-way in AC mode.

furnace under the fridge. don't wish to remodel the entire trailer.

[cavie]

Originally Posted by mwdilday

Who cares about efficiency. Either way you are spending peanuts.

$$$$, not peanuts every month. You'll change your tune when you get on a fixed income.

[mwdilday]

Originally Posted by cavie

My trailer stays on a permanent site. The electric is metered at commercial rates in MA. $.24 kwh. I determined that it would be much cheaper to run the fridge on propane vs electric. I've been told the freezer won't get as cold on gas. Anybody have experience in this? WH is on gas. Never thought of the fridge.

My gas electric fridge works great on either

[mwdilday]

Originally Posted by cavie

$$$$, not peanuts every month. You'll change your tune when you get on a fixed income.

I am on a fixed income

[mwdilday]

Originally Posted by davel1971

this topic really is that petty. We all could much easily find a way to save money over which fuel source to run the fridge on. Not worth racking your brain over a buck fiddy.

Yep

[davel1971]

Originally Posted by cavie

$$$$, not peanuts every month. You'll change your tune when you get on a fixed income.

I've been on a fixed income my entire life. Fixed to what my paycheck is.

[mwdilday]

The OP was asking if the Fridge would get cold enough on propane. Evolved into a debate over which is cheaper to operate and now we are debating whether we should be debating the cost to operate.

[davel1971]

Originally Posted by mwdilday

The OP was asking if the Fridge would get cold enough on propane. Evolved into a debate over which is cheaper to operate and now we are debating whether we should be debating the cost to operate.

So what you are trying to say is, this is just like every other topic and goes off track?

[mwdilday]

So I have done a little research on the Dometic RM1350M. According to the Dometic website this refrigerator consumes

Electric 610 watts which is 2081 BTU
Gas 2081 BTU

So the BTU is identical on Gas or Electric which tells me that the unit cools the same on gas or electric.

At 12 cents/KWH using .610 KWH it will cost 7.32 cents to power this fridge every hour it runs.

At $20 cost of a 30 lb propane tank and 640,500 BTU from the tank:

$20 / (640,500 / 2081) = .065/HR

Assuming that it will run 5 (I could only find one website that says they typically run 4-6 hours/day) hours/day then it will cost approximately $.325/day to operate or approximately $10/month on either gas or electric.

Now for residential fridges.

According to EnergyStar.gov it costs $65/year to run 20 cf residential fridge. That is about $5.50/month.

So the difference between RV and Residential fridges is about $4.50/month.



----------- References -----------------

https://www.energystar.gov/index.cfm...10&submit.y=10

Propane Cylinder and LPG Bottle Information

https://www.dometic.com/en-us/us/pro...specifications

https://www.chooseenergy.com/electri...ates-by-state/

[cavie]

Originally Posted by mwdilday

So I have done a little research on the Dometic RM1350M. According to the Dometic website this refrigerator consumes

Electric 610 watts which is 2081 BTU
Gas 2081 BTU

So the BTU is identical on Gas or Electric which tells me that the unit cools the same on gas or electric.

At 12 cents/KWH using .610 KWH it will cost 7.32 cents to power this fridge every hour it runs.

At $20 cost of a 30 lb propane tank and 640,500 BTU from the tank:

$20 / (640,500 / 2081) = .065/HR

Assuming that it will run 5 (I could only find one website that says they typically run 4-6 hours/day) hours/day then it will cost approximately $.325/day to operate or approximately $10/month on either gas or electric.

Now for residential fridges.

According to EnergyStar.gov it costs $65/year to run 20 cf residential fridge. That is about $5.50/month.

So the difference between RV and Residential fridges is about $4.50/month.



----------- References -----------------

https://www.energystar.gov/index.cfm...10&submit.y=10

Propane Cylinder and LPG Bottle Information

https://www.dometic.com/en-us/us/pro...specifications

https://www.chooseenergy.com/electri...ates-by-state/

Which brings us back to my origional post, @ $.24 kwh for electric I'm going with gas.

[rockfordroo]

Originally Posted by mwdilday

The OP was asking if the Fridge would get cold enough on propane. Evolved into a debate over which is cheaper to operate and now we are debating whether we should be debating the cost to operate.

No, the OP also commented on price of electric vs gas:

"My trailer stays on a permanent site. The electric is metered at commercial rates in MA. $.24 kwh. I determined that it would be much cheaper to run the fridge on propane vs electric. I've been told the freezer won't get as cold on gas. Anybody have experience in this? WH is on gas. Never thought of the fridge."