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Old 01-27-2014, 03:51 AM   #1
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Installing total electric heat

I would like to know the plus and minus of installing total electric heat and not using the propane heat that's installed. I have a 2003 Fleetwood Discovery 39 S model. It has 2 propane heaters in it now. 2 zones heat and A/C. The A/C I'm leaving as is. RV COMFORT SYSTEMS now makes a stand a lone heat system 50,000 btu system is $649.00 on line at Amazon. Normally is $850.00. It requires 50 amp service which I have. I sure would like to know your opinion on this matter pros and cons. thank you
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Old 01-27-2014, 04:56 AM   #2
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Don,

Excellent idea, however I have a huge problem with their fuzzy math used to determine BTU/hr. I have looked into these for some of my customers in the past, and admittedly have not talked to directly to anyone who has one.

1. I completely disagree with their math on the efficiency of electric vs gas. If you notice they are dropping the 40k btu/hr rating on the gas simply because of the times the fan/blower are running before and/or after ignition. This is inherently deceiving, and most importantly, incorrect. The BTU/hr rating should always be based upon the heat produced while it's heating, not when it's preparing to heat or cool down after a cycle since there is no fuel being consumed during either of those times. Smoke and mirrors marketing at it's finest.

2. They claim 40k btu "equivalent". Equivalent being the key word here. They are using the fake 100% electric efficiency rating coupled with including ineffective cycle times to effectively double the actual rated btu output as compared to LPG.

3. Here's the math. To figure BTUs we need watts. To get watts we multiply amps x volts. They are claiming 21amps per leg on 50amp. I will assume for the moment it would be a total of 40amps being used between L1 and L2 legs. Using the formula above we have 40amps x 120 volts = 4800 watts. Now to figure BTU we multiply 3.412141633 x watts which equals 16.4k BTU.

16k BTU in a 40' coach could simply not stay with the demand.

Here is another good example.... a simple handheld hair dryer is usually rated at 1600 watts. 1600 watts x 120v = 5.5k BTU. So you could effectively re-create their furnace with 3 hair dryers. (5.5K BTU x 3 hair dryers = 16.5k BTU)

The only way they could effectively get close to the same output as an LPG furnace is to step up to 220v, which they cannot do since the majority of gensets in coaches do not produce 220V.

4. You must be plugged into 50amp service to use their setup, which is still less than 1/2 the BTU/hr your LPG furnaces are rated at. If you use your genset, yours is probably an Cummins/Onan 7.5 Quiet diesel. Total output between BOTH legs is just under 65amps. Fire up these heaters and you're burning 42 of those amps. At that rate of demand (~70%) your genset will be using close to 1 gal/hr in diesel fuel. What if you're at a campground that meters your charges for electricity? Yikes.

5. Their figures used for AC amperage are way out of line. If each of your AC units are using 21amp there is something wrong.

6. Now.... everything above is based upon 1 40k BTU furnace... you have 2 furnaces. Therefore you'd need 2-50amp services to run both if you replace both, OR you run one on propane, one on electric.

In summary, if the electric units were truly any benefit then the manufacturers would be using them defacto standard. In all honesty you'd be better off to consider upgrading to a hydronic heating system of sort such as an AquaHot. Yes, the upfront costs are steep but if you intend to spend a lot of time in your unit, the ROI (return on investment) as compared to using electric could happen quite quickly.
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Old 01-27-2014, 06:05 AM   #3
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I forgot to add a #7 to the above...

7. Notice there are absolutely no CFM ratings on their standalone heating units. At only 4800 watts they would have to reduce the total airflow in CFM to obtain the same register/output temps that your LPG furnace would obtain. Blow too much air (in CFM) across the coils and they cool down substantially. Notice they do not publish consumption rates on their add-on units either. There are reasons.
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Old 01-27-2014, 09:12 AM   #4
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When we bought this RV the furnace was disconnected and in parts. Seems the previous owners were told it was broke and they should replace it. They just left it in parts. No problem for Thom, he fixed it and put it back together. Only thing is we just don't use it anyway. We bought a 1350 watt electric fireplace from Lowe's and have been using that for the last 2 winters. It pretty much heats the whole coach. When the temps do get below freezing and is supposed to stay there for a few hours we do then hook up a cube heater for the back.
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Old 01-27-2014, 09:33 AM   #5
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Am I correct in that I have heard only propane furnaces heat basement areas? If that is a problem, (depending on what is stored there and where the water pipes are), then cuibe heaters or heat strips in A/C units would not be a good answer in really cold temps.

We have generally used cube heaters, but this winter has been a strange one around Atlanta. I have about exhausted my propane, but teens are expected here again this weekend. My heat strips or whatever is in the A/C units just blows cold air even when the t'stat is set to heat-electric.
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Old 01-28-2014, 12:34 AM   #6
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94-Newmar, I want to thank you for all that info. That took some time and I really do appreciate it. I took the time to read every bit of it. That's what I like about sites like these, you get other RV'er opinions on a subject . And you sir seem to be very knowledgeable about this heat. And as you explained it, it made lots of sense. The other thing I wasn't thinking about was the basement and having to use 2 of theses units so I was exchanging the propane for diesel . The idea i had was trying to get to total electric. I wouldn't have to deal with propane at all, cooking or heating. So, i want to thank you again. I'll stay with what I've got until the real deal comes available.
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Old 01-28-2014, 12:46 AM   #7
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Retired and happy, in my coach the tanks ate between the coach and the basement and for what i've read they are heated. I need to call Fleetwood and ask them for sure they are there and how they are operated. Don't know if they heated with just the furnaces front and rear or they are heated from a heat strip when you use your heart.
From what I've read as for as yours if they are heated with the furnace and depending as to where your tanks are located you run the risk of losing your from freezing. I would suggest you contact someone who really knows you coach. Maybe someone here knows and will inform you as what you need to do. I wish you luck.
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Old 01-28-2014, 12:13 PM   #8
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Quote:
Originally Posted by donwat91 View Post
94-Newmar, I want to thank you for all that info. That took some time and I really do appreciate it. I took the time to read every bit of it. That's what I like about sites like these, you get other RV'er opinions on a subject . And you sir seem to be very knowledgeable about this heat. And as you explained it, it made lots of sense. The other thing I wasn't thinking about was the basement and having to use 2 of theses units so I was exchanging the propane for diesel . The idea i had was trying to get to total electric. I wouldn't have to deal with propane at all, cooking or heating. So, i want to thank you again. I'll stay with what I've got until the real deal comes available.
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I think the Cheap heat would be more than adequate in any temps you will be using your motor home. I have a 38' Winnebago and keep it above freezing in NE North Dakota until we leave the first part of January. I find that a 1,500 watt heater will keep the motor home 20F above outside ambient temperature. At 0F, two 1500 watt heaters keep it above freezing. The Cheap Will heat anything the propane furnace heats. I think it is a sound, useful product. I wouldn't hesitate to recommend it. I haven't seen any bad reviews.
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Old 01-28-2014, 01:51 PM   #9
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One nit to pick with you 94-newmar.

Of all the electrical devices I have, or ever will have,, Just exactly one group of them are, in fact, 100% efficient,,, For that is the only thing they can possibly be.. ELECTRIC HEATERS.

Why, Because all losses are expressed as heat, or become heat, You can talk about light that shines, or fans that blow, but it all becomes heat in the end, Thus no loss, thus 100%. Thus the only efficiency rating an electric heater can possibly have is 100%.

HOWEVER.. The rest of your post was dead on, They do use some ... Well your term "Fuzzy Math" is about the kindest thing I can say about it for figuring out the effect of the Propane.

From an "If I have to pay for the electricity" Propane is the only way to heat, the btu's per dollar generally way lower.

For many: here is why
Think about this Rube Goldberg system of doing things:

You burn fuel to heat and boil water to make steam which spins a turbine which generates electricity (Thomas Edison peaked the effiency of Generators back in Menlo Park and no significant improvement has been made since) which is then sent over wires, which of course are not perfect conductors and thus there is loss, LOSS OUTSIDE your RV where it is lost forever, and transformers (Again less than 100% thats why they have cooling systems) and more wires and transformers finally ending up in your motor home passing through a resistor making heat to heat your RV with.

Or this system: You burn fuel to make heat to heat your your RV with.

I mean with Rube's system, You had heat back at step #1.
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Old 01-28-2014, 01:59 PM   #10
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Agreed. In that context yes it's 100% efficient but using their fuzzy math then their electric efficiencies should be less than 100% as well

Did you re-read their justifications for dropping LPG efficiencies and overall btu rating thru the furnaces? How can they possibly include the time of combustion chamber evacuation before firing the gas into their reasoning for dropping the total btu rating? I love their usage of the term "equivalent". Unbelievable snake oil marketing at its finest. :-)
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Old 01-28-2014, 08:09 PM   #11
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As I said, I agree with you they are using bad math on the Propane side (I used the term "Fuzzy Math" quoting you in fact).

Just picking on the nit re-Electric heat, One of the things that really sets me off is when some company claims THEIR electric heater is more efficient than another electric heater. Because all of them are exactly the same, can't be anything else, 100%.

I do agree however that when you are trying to figure out how much heat you get from Peopane,, You only count the time the gas is flowing, NOT the time the blower is blowing.
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Old 01-28-2014, 08:44 PM   #12
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What is the cost difference? You technical types should be able to estimate that number which is what the OP originally was asking.
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Old 01-28-2014, 10:23 PM   #13
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In Quartzsite where I am now electricity is 17 cents/kwh. There are 3,412 BTUs in one KWH, cost per 1,000 BTUs is 4.9 cents.

In Quartzsite, cost per gallon of propane is $2.49. There are 109,000 BTUs in one gallon of propane. At 80% efficiency for a furnace that is 2.6 cents per 1,000 BTUs.

For a catalytic heater with 100% efficiency it is 2.2 cents per 1,000 BTUs.

So in Quartzsite right now electricity costs twice as much. However 17 cents/kwh is very expensive.
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Old 01-29-2014, 04:18 AM   #14
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Yes indeed. Electricity costs vary widely across the U.S. I found the average price right now is around 11 cents/KWH. The original OP never mentioned anything directly about the cost comparison of the various fuels but here is a layout of the BTU's and costs of the average pricing right now in the US to equal 1 million BTUs .....

Fuel source | Amount | Unit Cost | Total Cost for 1 mil BTU

DIESEL | 7.2 gals | 3.75 | $27.00
PROPANE | 11 gals | 2.50 | $27.50
ELECTRIC | 293KWH | 0.11 | $32.23

Using the 3rd column above, insert your own local price on KWH electricity or gallons of either diesel or propane and multiply by the 2nd column.
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