Adding an electric element to the LP water heater

[pdemarest]

I see several products (Camco and Hot Rod) on Amazon which are basically 400 watt heating elements that screw into the drain plug on the LP water heater to allow it to run on 110 volts. The kits include a cord to plug into one of the 110 volt outlets on the rv (problematic given that all but one of the outlets are up under the cabinets). The advantage - according to user reviews - is that when you are plugged into 110 volt power you can use this setup to run the water heater instead of using up LP, or as some suggested, use it in addition to the LP to get the water hot and then turn off the LP and let the electric element maintain the temperature. Anyone have experience with this setup?

[kdarling]

Nope, but I've thought about adding one of those electric elements.

Speaking of mods...

Have you looked at the tankless water heaters that fit in the same spot? Expensive, but the idea of hot water limited only by the water supply (infinite if external water hooked up) is very appealing.

(okay, limited by the amount of LP gas)

[Blue~Go]

I've never used a tankless water heater, so take this just as something to investigate if desired. But, I was told that one downside of the tankless heaters for smaller RV's is that they don't work very well with only a trickle to a small amount of water flowing through (i.e. being demanded). So to make them work well you have to use a fair bit of water for your shower or what-have-you. Might not be so good for off-grid water conservation mode.

Another note is that if anyone is going to be buying a new 6-gallon Suburban water heater (to directly replace the original), they do also come in a variant that has electric as well as LP mode (natively vs. via "hot rod").

[kdarling]

Tankless heaters are apparently being used in many new RVs, so any downsides must not be too bad.

A major advantage is that they tend to use less than half the propane of normal heaters, because they're not running all the time heating water unnecessarily. I suspect that in many places, water is easier to find than propane.

One trick with conserving water that I recently read, btw, is to turn the water heater temperature lower, so that it takes less additional cold water to cool off the hot water when taking a shower. Makes sense to me.

[Blue~Go]

Perhaps they're fine. Although just the fact that they are on new RV's doesn't sway me, because there are plenty of new RV's of which the systems are basically designed for RV park use. I realize not everyone boondocks, but if one does then it might be something to check before committing to one. Maybe they don't (or no longer) require high water flow. If so, great.

When I've spent longer times boondocking I have typically found that it's easier to find water here and there than it is to dump tanks. So I'm usually more concerned about what goes into my holding tanks. (Even without a toad, a friend offers a ride into town, brings you back a few gallons of water, or a campground has water spigots but no dump, etc.).

But again, they may be great. I was just mentioning a caveat that might be worth looking into before buying one.

A suggestion if one is looking to conserve propane with the typical 6-gallon tank type water heater: Before showering, start the water heater and let it get up to temp. Then turn it off. Shower, and then the water left in the tank will often make for enough warm water to do dishes etc. Firing the water heater for less than an hour per day takes very little propane.

As an option, mount a thermometer such that you can run the water heater just up to the temp you like, then you can take a shower with "all hot" and not have to waste water re-adjusting when you turn it on and off to soap up etc. (it will just always be at the same temp). Also, with a bit of distance between the water heater and the shower, having a container handy to catch the "it hasn't reached the shower yet" batch of water is good - then use it for other purposes.

Of course we all RV differently, so these tips may or may not be of interest.

[Scott]

As an option, mount a thermometer such that you can run the water heater just up to the temp you like, then you can take a shower with "all hot" and not have to waste water re-adjusting when you turn it on and off to soap up etc.

My shower head has a rotary valve on the back just for this purpose. You set your desired temp at the faucet, then turn on/off with the rotary valve to conserve while soaping up. No re-adjustment needed.

Aren't they all like this?

[pdemarest]

Haven't considered the tankless option before but I'll be checking out the cost. I was looking for a way to reduce LP usage when on a hook-up, not so much for cost as the inconvenience of running out of LP. As it turns out when I did refill my LP tank it was not nearly as empty as the monitor showed. Didn't check the gauge on the tank itself (bad knees makes it hard to get down there) to see if it matched the monitor readout but my new policy is to refill the LP when it reads half-full. Since we're headed into summer and our favorite site at the lake has no hookups I'm probably going to put this off until the fall.

[Blue~Go]

Scott: I wish! That sounds nice. I haven't seen another RV shower like you describe (not that I've seen more than half a dozen). I don't use the water heater (just got too used to heating up water on the stove during boat life, I guess ), but my buddy who uses it every day runs an aquarium thermometer (probe is under the water heater tank insulation). Just sets it to beep at X degrees (I think something like 95º) and then runs pure hot water in the shower - no adjusting.

Your rotary dealie sounds slick. Reminds me of Moen faucets (my preferred) on which the "on off" of the single lever is independent of the "hot cold" positioning - so you can set your temp and then just turn on and off. However, I'm still not sure that would work ideally for an RV. I think (but am not at all sure) that if you are "mixing" water you might still get a blast of "off temperature" water if you are turning it on and off a bunch of times for the navy style shower. The "use all hot" method (after you've heated the water heater to your preferred temp) eliminates that as there is no mixing. Every on off cycle is the exact same temperature.

But maybe your rotary switch does that too?

****

On the propane tank gauge: I cheat, since I'm often parked on gravelly/dusty ground. I hold my phone or a camera down there and snap a photo, then retreat to my comfortable living room and look at it

[Scott]

Scott: I wish! That sounds nice. I haven't seen another RV shower like you describe (not that I've seen more than half a dozen). I don't use the water heater (just got too used to heating up water on the stove during boat life, I guess ), but my buddy who uses it every day runs an aquarium thermometer (probe is under the water heater tank insulation). Just sets it to beep at X degrees (I think something like 95º) and then runs pure hot water in the shower - no adjusting.

That's definitely a great way to avoid heating more water than necessary. I'm going to try that with a digital meat thermometer.
I'm actually surprised to read that some folks continuously run their water heaters.
Here's the valve:

Also there's these valves for same purpose:

[Blue~Go]

I know, right? After you get used to it, running a water heater 24/7 seems so profligate! (Not that I'm saying no-one should - to each their own way.)

The aquarium thermometer seems pretty good. It has a probe (that you can stuff right next to the water heater tank), and then a little screen you mount wherever (wired). You can set the temp and when it reaches that temp it buzzes at you (then it's up to you to turn off the water heater). I thought it seemed like needless fluff at first (I like simple), but having tried both ways I think it's pretty slick. Eliminates that odd burst of un-desired water temp when you do the on/off thing at the showerhead when mixing hot and cold.