Tankless Water Heaters

[o1marc]

So I know everyone is different on what you "just must have" in your bus if you're going to be spending any significant time in it. One thing I don't want to give up are my long, hot showers. The other day I decided to do the numbers and timed my "normal" shower, and checked the water meter before and after to see how much I had used. I have a 40g. water heater. My shower was 15+ minutes and I used 36 of the 40 stored gallons before it starts to cool down (2.4g/min).
So my questions to those who use tankless water heaters are:
1) How hot can you get steady water?
2) How long will it supply that hot water?
3) Is my limitation the size of my fresh water tank?

[Willie_McCoy]

Originally Posted by o1marc

So I know everyone is different on what you "just must have" in your bus if you're going to be spending any significant time in it. One thing I don't want to give up are my long, hot showers. The other day I decided to do the numbers and timed my "normal" shower, and checked the water meter before and after to see how much I had used. I have a 40g. water heater. My shower was 15+ minutes and I used 36 of the 40 stored gallons before it starts to cool down (2.4g/min).
So my questions to those who use tankless water heaters are:
1) How hot can you get steady water?
2) How long will it supply that hot water?
3) Is my limitation the size of my fresh water tank?

My experience with tankless water heaters is limited to those in fixed houses, but most of the same principals apply. When you are looking at gas fired tankless water heaters what you need to research is its ability to raise water temp at a given flow rate. Most of the flashy advertising specs are for very low flow (=<1.5 GPM) so do your research. In your case, you want to flow approx 2.5GPM which is standard for shower heads in the US outside of Kalifornia. The Ecotemp L10 which seems to be a popular model for skoolies is rated at 75,000btu's but at 2.5 GPM this will only raise your water temp by 32* That would be woefully inadequate in a residential setting here locally, as we have to plan for incoming water temps around 45*(worst case scenario). If your only running it off of tank water, and that water is already at 70-80* then this might work for you, otherwise you will need something with more power. The other issue with large LP units, portable or fixed, is that once you get into the 150,000+ btu range, you will need to make sure your regulator is capable of those flow rates, and you will need more than a 20# propane tank. That grill cylinder will be iced up and frozen before you get the soap out of your hair if your trying to pull 200,000btus out of it. Once you get this figured out, and get a properly sized unit, your hot water will be limited only by your water tank size, and your fuel supply.

[o1marc]

Originally Posted by Willie_McCoy

My experience with tankless water heaters is limited to those in fixed houses, but most of the same principals apply. When you are looking at gas fired tankless water heaters what you need to research is its ability to raise water temp at a given flow rate. Most of the flashy advertising specs are for very low flow (=<1.5 GPM) so do your research. In your case, you want to flow approx 2.5GPM which is standard for shower heads in the US outside of Kalifornia. The Ecotemp L10 which seems to be a popular model for skoolies is rated at 75,000btu's but at 2.5 GPM this will only raise your water temp by 32* That would be woefully inadequate in a residential setting here locally, as we have to plan for incoming water temps around 45*(worst case scenario). If your only running it off of tank water, and that water is already at 70-80* then this might work for you, otherwise you will need something with more power. The other issue with large LP units, portable or fixed, is that once you get into the 150,000+ btu range, you will need to make sure your regulator is capable of those flow rates, and you will need more than a 20# propane tank. That grill cylinder will be iced up and frozen before you get the soap out of your hair if your trying to pull 200,000btus out of it. Once you get this figured out, and get a properly sized unit, your hot water will be limited only by your water tank size, and your fuel supply.

Lots of good info there, Thanks Willie

[PNW_Steve]

Originally Posted by o1marc

Lots of good info there, Thanks Willie

+1 Thanks Willie!

[o1marc]

Sounds like my 140°, 15 minute showers is a no go.

[PNW_Steve]

Boy Marc, you would not have been a happy camper at our place on the West side.

We relied on rainwater collection for our domestic water. That made for some lifestyle changes like 3.5 gallon " Navy" showers.

[Tango]

"3.5 Gallon Navy Showers"?


Must be the "new" Navy. We got 1/2 gallon max on "water hours"

[family wagon]

I've been pondering how I might build a recirculating shower. The idea would be to use the first few minutes and gallons of shower time getting soap etc taken care of and let that water drain away. Then flip a valve and start recirculating water for the hydrotherapy session. Recirculation would significantly reduce the need for both water and fuel while the shower drags on and on..

There are a few little challenges related to keeping the recirculated water separate from the potable water. Need a separate pump, a separate heater (or heat exchanger, at least), and backflow prevention at the shower valve or head.

Has any of you seen any cleverly simple implementation?

[Ronnie]

We have one in our bus, and had one in our camper for many years. They are both Marey units. This being the gas fired on demand heater. It can be used outdoors connected to a garden hose or used inside connected to you water pump. If inside you can get it with a vent pipe connection for exhaust gases.

Our water tank is in inside the bus as we do not want it to freeze, no showers then...

Our experiance is that we can have as hot of water as one wants for a long as you have water. We have a 105 gallon water tank. A 15 minute hot shower is fully possible, and on rare occasions I have done that. Mostly tend to do "navy showers" though, although not as short as Tango mentions. We use the shower head that comes with it, and it is plenty of water. I do not know what the flow rate is, however it is more then enough for a nice comfortable shower.

[milkmania]

Originally Posted by o1marc

Sounds like my 140°, 15 minute showers is a no go.

I've had my Eccotemp L5 going on 3 years, setup outdoors with stainless/rubber garden hose hooked to clothes washer and shower... I can hit 194 degrees as long as I want, by manipulating a ball valve on the inlet side, or the one on the outlet side. I have great city water pressure, so I'm just slowing the flow. And the flow is negligible from the shower head itself.

I've done the exact same steps using the 12v pump from harbor freight and a 55 gal poly drum. Same results.
Only limited by the amount of water or propane you have.

and I've done it this way for years!

[EastCoastCB]

A guy I work for builds tiny houses for big bucks. He's been installing some kind of tankless heater in them. I've heard nothing but good things about em.
If I were going to get a water heater I'd probably buy what he's using.

[Daledorm]

We are building our shower base on this system of a recirculating Shower. You can take as long of a hot shower as you wish on just a few gallons of water and reuse it multiple times.

With a 40 gal fresh water tank, every drop counts!

https://youtu.be/GgEmHj7iRdQ

[Busnbuster]

Look at Bricor shower heads. They are not cheap , but you can go as low as .625 gals. per minute. We installed the Ultramax in our campers. They cost 75 bucks but are worth it if you a serious about water saving and a great shower.

[mmoore6856]

Originally Posted by Daledorm

We are building our shower base on this system of a recirculating Shower. You can take as long of a hot shower as you wish on just a few gallons of water and reuse it multiple times.

With a 40 gal fresh water tank, every drop counts!

https://youtu.be/GgEmHj7iRdQ

we are also going with a system we found on a website called shower loop. its a open source project that will give you lots of info about doing it yourself. i wont need a low flow or have to limit my time in it. however be prepared for some snarkey comments i have received from the bathtub crowd that thinks its dirty water.

[musigenesis]

Originally Posted by mmoore6856

we are also going with a system we found on a website called shower loop. its a open source project that will give you lots of info about doing it yourself. i wont need a low flow or have to limit my time in it. however be prepared for some snarkey comments i have received from the bathtub crowd that thinks its dirty water.

There's a bathtub crowd?

[mmoore6856]

Originally Posted by musigenesis

There's a bathtub crowd?

horse tanks mostly

[lewirj]

We've been on the road for a year in our skoolie. We have a Girard 2GWHAM and have been happy with it. We can get 115F water as long as there is propane. If you turn off the water to soap up the water temp drops for 20 seconds or so.
It has a freeze guard feature that kicks on every few minutes when the core temp drops below 38F heating up the unit.

[Willie_McCoy]

I am always surprised to see my own replies when these old threads get dredged back up.

Originally Posted by lewirj

We have a Girard 2GWHAM and have been happy with it. We can get 115F water as long as there is propane.

This is the unit we have decided on as well, glad to hear it is working well for you. I am still searching for a black door though.

[Muchee]

Originally Posted by milkmania

I've had my Eccotemp L5 going on 3 years, setup outdoors with stainless/rubber garden hose hooked to clothes washer and shower... I can hit 194 degrees as long as I want, by manipulating a ball valve on the inlet side, or the one on the outlet side. I have great city water pressure, so I'm just slowing the flow. And the flow is negligible from the shower head itself.

I've done the exact same steps using the 12v pump from harbor freight and a 55 gal poly drum. Same results.
Only limited by the amount of water or propane you have.

and I've done it this way for years!

Hey Milkmania!

I have a Eccotemp L5 and it’s shot! I’ve been having issues with the water/gas assembly leaking water. I talked to the company and they said once you have a freeze it’ll break it. I live in Georgia lol, so no freezes here. How has yours been working since you live in an area that does freeze?

[ladybird_bus]

Originally Posted by o1marc

So I know everyone is different on what you "just must have" in your bus if you're going to be spending any significant time in it. One thing I don't want to give up are my long, hot showers. The other day I decided to do the numbers and timed my "normal" shower, and checked the water meter before and after to see how much I had used. I have a 40g. water heater. My shower was 15+ minutes and I used 36 of the 40 stored gallons before it starts to cool down (2.4g/min).
So my questions to those who use tankless water heaters are:
1) How hot can you get steady water?
2) How long will it supply that hot water?
3) Is my limitation the size of my fresh water tank?

I have a Furrion tankless and I got it because I have a bathtub in my rig and wanted to be able to fill it in about the same time as in a house. I did a LOT of research before going with this one. It wasn't cheap - around $800 when I got it and that was three years ago - but worth the money, at least for me. It delivers water at whatever temp you set it to (I have it at 120F) basically as long as it gets water and propane. A 20lb tank lasts me for weeks of showering and dishes (currently at a month on one tank) or about 10 days-2 weeks if I take a bath every day.