10 Gallon or 12 Gallon Water Heater?

[Rob Hentges]

The suburban 10 gallon water heater in my 1996 gulfstream 39ft diesel pusher needs to get replaced due to rusted tank. I have read that the 12 gallon model fits the same opening as the 10 gallon. The gas/electric versions of each size only vary by $60 using internet pricing. Is there any downside with spending the extra $60 and getting the 12 gallon tank instead of the 10 gallon?

[NeilV]

Only that the 12 will be heating more water to maintain temperature with the potential to cost more to run. What are the feed line requirements of the 12 over the 10? Is a larger diameter gas line required for the 12?

One would think that the insulation may be thinner on the 12 in order to get the larger tank into the same space again with the potential for lower efficiency.

Traveling with three women (wife and two adult daughters) who take long hot showers I have never run out of hot water with the 10 gallon tank in my coach so I would not be inclined to go larger.

[Mr_D]

Probably true about the thinner insulation, but the new insulation is probably better due to the advancements made in materials.

[the_vfox]

I would verify the dimensions first, then if the same, use the 12 gallon one. Never know when you need the extra capacity.

[NeilV]

Originally Posted by Mr_D

Probably true about the thinner insulation, but the new insulation is probably better due to the advancements made in materials.

Same would be true with the new 10 also and there would be more of that new insulation around it. Myself I have not had the 2001 version of the 10 gallon heater run out so unless I had a bunkhouse model with 6 or 8 people living in the coach I would not have a need for more.

Many would be considering ditching the tank type heater altogether now and be looking into a tankless model and stop maintaining the 10 gallon thermos of hot water.

[Rob Hentges]

Originally Posted by NeilV

Only that the 12 will be heating more water to maintain temperature with the potential to cost more to run. What are the feed line requirements of the 12 over the 10? Is a larger diameter gas line required for the 12?

One would think that the insulation may be thinner on the 12 in order to get the larger tank into the same space again with the potential for lower efficiency.

Traveling with three women (wife and two adult daughters) who take long hot showers I have never run out of hot water with the 10 gallon tank in my coach so I would not be inclined to go larger.

The 12 gallon is longer, goes deeper into the RV. That is how they get the extra 2 gallons in. Therefore the insulation should be the same thickness. I believe the heating element and burner are the exact same. The 12 is basically a slightly stretched version of the 10. My water heater is in an outside storage compartment, so extra length is not an issue.

[Rob Hentges]

Originally Posted by NeilV

Only that the 12 will be heating more water to maintain temperature with the potential to cost more to run. What are the feed line requirements of the 12 over the 10? Is a larger diameter gas line required for the 12?

One would think that the insulation may be thinner on the 12 in order to get the larger tank into the same space again with the potential for lower efficiency.

Traveling with three women (wife and two adult daughters) who take long hot showers I have never run out of hot water with the 10 gallon tank in my coach so I would not be inclined to go larger.

I took your advice and stuck with the 10 gallon gas/electric. Ordered from ppl motorhomes. Arrived in 4 days. Plan to install today.

[peggwn]

NeilV, I don't know that this will apply or not to your comment about a tankless heater in an RV. When we built our home back in 1995, we went "efficient" and installed a tankless for the reason you mentioned, and because we had used them in other countries and of course of course had constant very hot water. However, when ours gave up the ghost a couple of years ago, we switched to a hybrid water heater that mainly uses propane, but also incorporates a reverse heat pump to help maintain and reheat the water as it's used (as an extra benefit, it actually blows/dumps the extracted cool air out into the garage). The reason I mention this is that we now use a third of the propane we used to, and have seen only a negligible increase in electricity usage.

The propane part of the comment, though, is the important one. Tankless only turns on when water is flowing; but boy does it turn on! They suck propane and lots of it to maintain that constant heat. Just an experienced observation. Good luck.

[Mr_D]

My parents ordered a European tankless water heater in their 1958 (yep in 1958) Ken Craft 18' TT. It seemed to work well except for the breakaway screws that did what they were supposed to do if the unit froze! At that time it was impossible to find the metric thread, shouldered, breakaway head screws. Not sure what dad did to get it working again.

[Rob Hentges]

First camping trip with the new 10 gallon water heater. Glad I didn't spend the extra money on the 12. Was able to take a nice long shower with very stable water temps.

[NeilV]

Originally Posted by peggwn

NeilV, I don't know that this will apply or not to your comment about a tankless heater in an RV. When we built our home back in 1995, we went "efficient" and installed a tankless for the reason you mentioned, and because we had used them in other countries and of course of course had constant very hot water. However, when ours gave up the ghost a couple of years ago, we switched to a hybrid water heater that mainly uses propane, but also incorporates a reverse heat pump to help maintain and reheat the water as it's used (as an extra benefit, it actually blows/dumps the extracted cool air out into the garage). The reason I mention this is that we now use a third of the propane we used to, and have seen only a negligible increase in electricity usage.

The propane part of the comment, though, is the important one. Tankless only turns on when water is flowing; but boy does it turn on! They suck propane and lots of it to maintain that constant heat. Just an experienced observation. Good luck.

I guess I wasn't clear that I am not amongst the many who would consider the tankless units. I personally feel the 10 gallon insulated tank is efficient enough for me and would not want to deal with providing the larger propane and electric feeds that the tankless units need however it is an option that many passionately pursue.

In my home I would have to start upgrading at the utility pole and/or upgrade the gas pipe along with the regulator if I went tankless however I would seriously consider staying with the tank and going with a solar hot water system before spending that much on the tankless unit.

My brother went solar a few years ago and is extremely happy with the results. He lives right next door to me in Sunny Tampa Bay Florida so we are in the right location for it.

[wa8yxm]

I agree the 12 will cost more to operate but. except for tankless water heaters.. The bigger the heater the longer the shower.