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To replace gas/elec Dometic or Not?


charlyhors

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As we plan for installing solar, and are getting our energy usage numbers together, I am debating replacing my Dometic gas/AC refer with a domestic refer which would run off a solar panels (2), extra batteries (2) and a whole house inverter. Just playing with whether this makes sense.

 

From what I've read, looks like our 7-8 cubic foot Dometic refer would likely use about 1.2 lbs of propane a day, lasting about 16 days on a 20Lb bottle, and costing about a dollar a day in propane. It's been more difficult to find the estimated electrical usage of this refrig. A watt meter shows it using about 350 watts during the daytime summer hours, and mostly off during the cool night. That calculation would end up being about 1800 KWH per year, or about 5 KWH per day to run my present Dometic gas/ac unit on solar electric.

 

The 10cu ft Whirlpool residential refer from Home Depot says it uses 380KWH per year, and cools 2-3 more cubic feet of space. So the residential refer is about 5 times more efficient that the Dometic RV frig.

 

So, I guess the trade off is going with existing setup - propane costing about $360 year for the frig, or spending the additional bucks of 2 solar panels (about $300) and 2 batteries (about $200) and the frig ($420). So that's about $1000 for the extra solar components, leading to less than a 3 year payoff. Think I answered my own question.

 

What do you think of my calculation. Do my estimations fall down any where?

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Makes sense, the RV fridge is just running an electric heater to replace the propane flame so it isn't going to be anything close to efficient. Lots of good topics around here on picking a fridge, either a 120 volt home model or a few with direct 12 volt power so you don't need the inverter.

 

If you have a Kill-A-Watt meter it has a total watts used counter in it that can give you a daily or weekly total to get a better idea of your electrical use over time.

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That seems awfully high for propane use? What do you base the amount used on? Keep in mind that the cooling unit actually opperates far less than constantly, especially in moderate climates.

 

I'm not saying that it isn't justifiable, but can't think that the use is that high. I'm not a dry camper so don't have a lot of experience in that sort of thing but have run an RV refrigerator on propane(electric when parked) while traveling as well as a water heater exclusively on propane and our tanks last far more than 16 days.

 

In your case I sure would look at the change if replacing the refrigerator anyway, but not so sure as long as it is operating well.

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Kirk, I got the information from this link on EHow http://www.ehow.com/info_12182501_much-propane-propane-refrigerator-use.html

 

They say 1.5 pounds a day for a 12 cu ft frig, I lowered that to 1.2 pds for a 8 cu foot, maybe should be more like 1 lb a day. I have Not always found Ehow reliable.

 

I've read everything from a person claiming they got 5.5 months for frig and HWH on a 20 gallon tank to someone stating that Dometic says an 8 cu ft frig will use 1/4 gallon (1 pound) per day. Anyone else know how much propane a normal size RV frig uses?

 

Kirk, how big are your tanks, and what would be your estimate for how long they last using frig and HWH?

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Personally I would not remove a working RV fridge and install a residential fridge.

 

You could plan your solar install for the additional panels, but not install them. If or when the Dometic dies, you could add the extra solar and the new fridge. I would go ahead and and add the extra batteries if you plan a lot of dry camping/boondocking. The extra batteries will give you extra capacity for cloudy days.

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Al Florida: I removed a working RV fridge because I already knew I could not replace it myself and there was going to be a delay in getting a residential that would fit. I was right on both points, I did not have the skills for the full install and the new fridge took over a month to arrive. I also had experience waiting for a new cooling unit when our old one died, it took a week to arrive and messed up our travel plans. Your situation might be different, you can do all the work and have many choices from local hardware stores.

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Agreed, there are reasons why someone would make a personal decision to replace a working RV fridge with a residential fridge.

 

Personally, the RV refrigerators, I have used for the last 10 years, work well enough to suit our needs. For the most part the RV fridge's will work for many years before failing. We did have one break on us, all the coolant leaked out. We lived with food in coolers for 3 weeks waiting for a replacement fridge. We were lucky that the RV Park we were staying at allowed us to store our frozen food in their freezer for the 3 weeks. Just another "interesting adventure" in the life of using an RV.

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After our 11 year old Dometic NDR 1292 fridge just died (ammonia leaked out), we were torn between what was the best thing to do. We were told a lot of them around the 7 years to 13 years were dying according to the calls the folks that sell refurbished or new systems were getting. To just replace the coolant system we would have been around $1400 including delivery and self install, but as was pointed out, we still had 11 year old components on the rest of the fridge. Thankfully ours failed whilst we were on down time generally from any long travels, and for the time this project is taking us, I'm glad it didn't happen on the road, although if it did we'd just have paid a mint and got an RV dealership to have done it all I guess.

 

"If" the price of a replacement Dometic wasn't so high ($4500 we were quoted) we would likely just for quick ease have replaced it = the path of least resistance :D . However, if we are honest our ice cream and breads always remained somewhat soft in our old Dometic freezer, so not that good at cooling. We chose to use that money to buy a residential GE Fridge ($620), 8 x new batteries ($720 with core charge), and we still have about $4000 to complete the inverter, charge controller, monitor, cables, panels etc towards full solar.

 

So for a little more than the cost of a replacement Dometic, a lot of help from many other folks, and tremendous frustration and patience, on the surface it appears we will have a better efficiency residential fridge, and the capabilities (one day LOL) to be totally off grid which we have always preferred in our travels.

 

In all fairness though, I wouldn't have replaced it if it was still in full working order. If anything, it's failing forced us to stop lamenting and get on with solar which really is going to a huge positive for the way we like to travel and stay.

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The timing on this subject is great.

Our trustworthy Norcold quit last Monday! Overheat thermocouple tripped first. bypassed it direct to the board (troubleshoot only) and the refrigerator came on. two hours later, No Cool warning came up! Checked the boiler: cold! No leaks and no yellow powder or ammonia smell. Blocked ammonia channel. Talked to two RV repair techs, both said we could "bang on the tubes or remove the unit and BURP it" ENOUGH!!!

 

Was thinking about a Residential unit, this made my mind up. Gathered all the info on replacement of gas cycle refrigerators vs. compressor systems. Went out on internet and found the best fit for us is the Samsung rf197. turns out they are getting rare. They must be popular.

 

Bottom line, found one for $1100 plus free shipping. Now have to wait the 10 days to get it shipped in here.

 

I know others on this forum have done this, any comments?

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  • 2 weeks later...

Just my 2 cents at half off... but I would really take a lot of the "fuel" (elec, 12v, gas, solar, genset, h2o) estimates you see with a grain of salt. YMWV. My best recommend would be to take it out on the road under normal usage and see where you end up. Weigh your LP tanks before you head out... ensure your batteries are fully charged... then make a tally sheet you can hang somewhere convenient. Record how many lights your burning and for how long. How many stove burners did you use and for how long. When and at what time did you start the fridge. etc etc. Get my drift? Try to avoid seasonal fuel expenditures like A/C, the furnace, tank heaters, etc. When you get home, re-weight your LP tanks, check the charge on your batteries, drain and measure what's left in your fresh water tank, etc etc. Then do the math again.

 

Just taking propane usage by your fridge as an example there are just so many variables. What climate do you generally camp in, what elevation, do you keep your fridge and freezer nearly full or barely, do you precool your food at home or just toss it in at room temperature from the grocery store, while camping do you cool your food before storing, what temperature do you keep the inside of your rig, are you the type to stand there with the door open and wonder "what looks good.. hmm"... and on and on.

 

So one feller with the exact same fridge may only burn 1/8# a day while another feller might burn 2#+. Question is... what do YOU burn a day. The same goes for all of your other onboard fuels and resources.

 

One other thing to consider in your calculations with a domestic refer... if you have a few cloudy/rainy days and your solar can't keep your batteries charged enough to run your refer, then you're looking at the cost of gasoline to run your genset. Best case.. what? $3-5 a day in gas?

 

My personal style... versatility. If I've juice galor in my battery bank, it's a beautiful sunny day and I'll be out and about till late and will be hitting the hay early (no TV or such later)... I'll probably run my fridge off the inverter. If it's a cloudy day and the olympics are on (TV and receiver will be going 24/7 with plenty of microwave popcorn)... my fridge is eatin propane. LOL

 

Design your systems to fit YOUR lifestyle... not something you read on the internet.

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  • 2 months later...
December 9, 2014

I am not even looking at the energy usage. We are looking at no water in the refrigerator from coils frost. No temperatures fluctuating from 40 to 60 degrees inside the refrigerator. No defrosting the freezer. Ice cream that is not soupy in the refrigerator after a day. Things stay frozen. Milk not going sour. We are going to change to the Samsung 17.5 cf refrigerator we have 4 6 volt house batteries and planning to add 2 more. Solar 520 watts.

George

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Apparently in agreement with Yarome. Propane seems to last quite a while when we are not using the forced air heater. We only use the forced air heater to warm up the rig in the morning (20 to 30 minutes) and use the Olympian Wave 8 once it is warm.

 

We have considered this but we sometimes have to dry camp and boondock/bush camp with no solar for 4 or 5 days and have decided to stay with Dometic electric/propane. We have sufficient solar/battery bank to run the Dometic on AC during the day and turn on the propane at night. In mid-summer, we just leave the Dometic on AC and wake up to a -2500 to -3000 W-hr deficit.

 

The same is true with a split level a/c. It would cost a lot to buy and install and we have enough solar and battery bank to run the Dometic a/c 3.5 hours during mid-summer. So have discussed this and decided not for now.

 

Reed and Elaine

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  • 4 weeks later...

We have been seeing the migration to residential refrigerators but have never felt the need. We have a Dometic and the food is frozen, the temperature flucuations are about 4 degrees on a hot day. We don't keep ice cream in the freezer but we do keep bread and it is frozen solid.

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I do have a question though. Normally we see comment about the Norcold 4 door(a 4 door is on the wish list) but never the Dometic. My gut feel is the Dometic is a better refrig(we have always had Dometic and no failures or problems). Appreciate any comments one way or the other.

 

Tbhanks

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I have had mostly Dometics as well, and have found them to be relatively trouble free until they aren't. Based on my own experience as well as that of many others, once you reach the 10 year mark on either Dometics or Norcolds you are living on borrowed time. Sure, there are some folks who get many more years than that from their gas absorption refrigerators, but that seems to be about the point when many fail as well.

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