Tankless water heater or not?

river place · January 18, 2009, 09:41:16 AM

Before we begin build our house we're going to use a 10x30 end section of our pole barn for a 10x10 bathroom and 10x20 den for guests as the travel trailer gets a bit too crowded. The bath room will only need hot water for a shower and sink.

I have an LP tank so that's my choice for fueling a hot water heater (don't want to rely on expensive electric for powering it or running heater controls). The water will only be heated when we are there 1 to 2 weekends a month. Water heater will be in the 10x10 bathroom. The pro's of going tankless are minimal space and being effcient. I thought about with a 20 to 30 gal tank heater but they take up more room, less effcient and take longer to heat up, they do however cost less and might be a bit easier to maintain.

Any thoughts on the pro's and con's and if tankless what about the Bosch or Rheem units

John_M · January 18, 2009, 09:59:25 AM

I am considering the same for my cabin as well. I think you need to determine how long you will be there. The tankless will be less money in the long run. I am leaning towards the tankless because of that reason along with the space saving issue as well!

January 18, 2009, 10:03:08 AM

We have the Bosch HX125 - powered by its own dynamo as the water is turned on. No need for wiring or batteries. We are very happy with it. Some have complained of problems with it but we have not had any.

It has been superseded by

http://www.amazon.com/Bosch-1600H-LP-AquaStar-Tankless/dp/B000KXZLE2/ref=sr_ob_10?ie=UTF8&s=hi&qid=1232290404&sr=1-10

MountainDon · January 18, 2009, 12:49:33 PM

The frequency of use, as mentioned, is one factor to consider.

Another important one to me, is how easy is it to drain if the building will be left unheated in freezing weather. The only reliable method is to blow them out with air, IMO. Some impossible to gravity drain.

If you can get by with a small tank, it could be the better choice, depending on how much use it will get.

However, if you are building a larger house to be lived in later the question of what will be done with this bathhouse after the house is up? Will you still use it or will the heater be transferred to the main house? In that case, if it's a full time residence, I'd go for the tankless heater. As for what brand, I lean towards the Rinnai. But, Rinnai is smart enough to know that not all water is equal. Water with high mineral content can cause problems with scaling in a tankless heater. Rinnai won't warrant their heater in many ZIP's in NM because of that. I don't know about the warranty limits on other brands; worth checking on before taking the plunge.

One other thing that confuses whether to choose tank or tankless. That is the plumbing layout of the house (how sidely separated points of use are). Our home has our bathrooms located a good distance from the water heater location. It used to take several minutes for warm water to reach the sinks and showers at that end. Running purchased water down the drain in the desert was a real waste. If we'd had a whole house tankless installed in the same place we'd maybe been saving some on gas to heat the storage tank, but would still have had the water waste.

We now have a hot water recirculation pump. This timer controlled small pump ensures that hot water is available at the sinks and showers virtually instantly during those timer runs. This would not have worked with a tankless.

In a floor plan such as ours two tankless heaters might be the ideal. But even more costly.

If you have a small compact house that would be less of a consideration.

phalynx · January 18, 2009, 04:55:35 PM

I will say I do love my tankless. I really like the fact that on a cold morning when you reall just want to be warm, you never run out of hot water. Be sure to make sure your tank is large enough to handle a tankless though. They usually have a minimum size tank requirement due to freezing and evaporation requirements because of the high BTU output.

January 18, 2009, 06:49:47 PM

The area in the barn will stay even when we build the house. I will have the ability to blow out a tankless unit with a compressor so that's a possibility. The barn could freeze so being able to just drain a tank unit would be nice as this is what we do with the trailer now.

Maybe the low risk approach is a small tank unit for the barn and go tankless in the house. The house will be an L-shaped dogtrot design so the plan is two tankless units in the house

MountainDon · January 18, 2009, 07:10:16 PM

Depending on whether or not you are in a code area, an RV water heater could be used in the barn.

river place · January 18, 2009, 07:40:11 PM

After thinking about it a bit more and the need to drain the unit when we leave I think the tank unit would suit my needs for now.

The RV unit is a possibility based on size and easy to mount in the side of the barn just like the trailer. The largest I could find was 12 gallon but the recovery time seems good (Suburban brand). I wasn't able to find clear info on the ignition/pilot light as I want a heater that doesn't require and electrical source to run. We're down a remote road and power could go out in an ice storm.

If I go with a home type unit the Bradford White unit seems to have a very good reputation. I just need to find a plumber friend to buy it for me as they are not sold direct to consumer.

MountainDon · January 18, 2009, 08:28:56 PM

It appears that the 12 gallon Suburban is a new model and is direct ignition only. That means it needs 12 VDC to operate. A battery would do. There is no pilot light, just an spark ignitor. It also comes with a 120 VAC electric element.

January 18, 2009, 08:47:09 PM

The option would be to use a spare motocycle battery and hook it to a battery tender

FrankInWI · January 18, 2009, 08:50:48 PM

WARNING.... STUPID QUESTION COMING !

I am just going with a tank unit for now, mostly cause of expense. I imagined I would have to drain the tank unit too when we're going to be away in freezing weather... I would have to, right? I mean I can't just let the water in the tank freeze and turn it on when I come up, can I? Oh...I am probably going to use electric for now. Infrequent use and I don't want to put a hole in the roof for venting. When I build the house we'll do something else.
Thanks

MountainDon · January 18, 2009, 08:55:08 PM

You must drain the tank. Virtually all tanks today use glass lined tanks. Freezing would cause the ice pressure to crack the glass. At the very least that will lead to short life. At worst the tank would crack and split and then leak as the water thawed. Plus any water in the valves anywhere will freeze and break/crack them. I've been there, done that.

river place · January 20, 2009, 05:08:56 PM

The 12 gal Suburban water heater is looking better. It seems that most places have them on sale (slow RV biz?) Prices don't seem to bad and easy to install. Just need to find out about the controller that turns on the ignition and turns it off if pilot light does not start burner.

MountainDon · January 20, 2009, 06:29:12 PM

Quote from: river place on January 20, 2009, 05:08:56 PM
(slow RV biz?)

Darn right. RV manufacturers are one of the more endangered businesses.

The RV water heaters with firect ognition are very simple. There is an on-off switch placed inside the RV. When you want to turn it on you flip the switch. The controller board in the heater runs through its program, turns on the gas, ignites the burner. When the water reaches the set temperature the gas is shut off. If/when the water temperature falls to the set point the controller repeats the cycle. Turning off the switch shuts it down. A 12 volt DC electrical supply is required.

I've found pplmotorhomes.com in TX to be helpful over the phone.