# tankless water heater



## Ted n Ms (Apr 25, 2008)

Thinking about installing a tankless LP water heater in my honey house. It will be like most it will be used only about six or seven days a year. Anyone use tankless.


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## treeWinder (May 3, 2013)

Good idea, I don't have one but seems like you'll save $'s.


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## mathesonequip (Jul 9, 2012)

if you are going to only use it a few times a year put in a cheap electric one. the tank-less is best if used everyday. it is money to spend that the fuel savings will never pay for in your situation. not using it for long periods will cause more not less maintanence. drain the electric in the off season, shut off the power when not in use, remember to fill and turn it on the day before you use it.


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## Jaseemtp (Nov 29, 2010)

I have two in my home and they are gas powered. They are amazing! Instant hot water and a near limitless supply of it. I had the plumber unlock the one for the master bath and I use to mix sugar syrup and to clean up after extracting honey. 140 degree water makes all that a snap. love love love it


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## Ted n Ms (Apr 25, 2008)

mathesonequip said:


> if you are going to only use it a few times a year put in a cheap electric one. the tank-less is best if used everyday. it is money to spend that the fuel savings will never pay for in your situation. not using it for long periods will cause more not less maintanence. drain the electric in the off season, shut off the power when not in use, remember to fill and turn it on the day before you use it.


The problem is that i have a tri-plex line that runs from my brother-inlaws house to a dairy barn that is my shop and honey house. I am trying to cut his costs. That is why i am going with propane.


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## Rader Sidetrack (Nov 30, 2011)

It seems to me that Matheson is on the right track even if it is your brother-in-law's power bill. Use an inexpensive electric tank heater, but shut it off for the non-honey season - and pay your brother-in-law some cash for the few days that you do use hot water from the electric tank. The savings from not installing propane should leave plenty of free cash available.


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## Ted n Ms (Apr 25, 2008)

>The savings from not installing propane should leave plenty of free cash available. <

The thing about propane it does not have to installed. I can use a portable bottle as little as i will be using it.


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## mathesonequip (Jul 9, 2012)

if and when a tankless heater screws up it is a lot more expensive to repair. if you use it daily it is usualy quite dependable, siting unused for months is not helpful.


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## Rex Piscator (Oct 12, 2010)

We've replaced an old Bosch[first generation type...] with a newer one. We love it, except when it goes on the fritz; takes a very well trained tech to fix it. Our brand, Noritz, doesn't like a dusty environment, gets an error and won't stay lit. This requires lots of attention to dust in the utility area. Endless hot water is very nice, really doesn't make sense to continually heat water you don't use?!? Thing sounds like a jet engine when it fires up though, quite the heat exchanger in these things! All in all, we like it over the large tank variety; did I mention _endless_ hot water, lol!

Definitely do some research into the units...


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## mathesonequip (Jul 9, 2012)

renai is probably the best brand of the bunch. at least that is what I have seen on dairy farms. I doubt I will ever put one in for myself.


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## BeeDub (Mar 11, 2013)

If it is only going to be used in your honey house for a week out of the year then a "Point-of-Use Electric Water Heater" may be the way to go. They connect at the source/sink, and cost at or below $200.


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## John R C (Mar 15, 2011)

If you get be I would recommend a rheem or rinnia in that order. After installing alot of these I can tell you that they will give you an endless supply of hot water if sized properly. If you do get one spend the star $50 or so for the commercial chip that'll give you 185* water. It's real nice for mixing 2:1.


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## marant (Jan 18, 2014)

We have a tankless for the main bath, which works very well. But for the kitchen sink, which is far enough away from the tankless that it takes forever to heat up I installed a small 2 gal electric beneath the sink, to provide water until the tankless water gets there. It is a simple install, plugs into an outlet, and provides instant very hot water. I suggest a small electric unless you need a lot of water. Much less expensive than a tankless propane, and probably also much less expensive to operate.


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## Hoot Owl Lane Bees (Feb 24, 2012)

Just for (* comparison *) I checked our local Lowe's price's.
30 gal gas water heater $401.24
Gas Tankless water heater $848.00
For even 2 week's use that is half price.
Use your 20 lb. tank and drain, then remove it and fire up the grill with some Honey BBQ Ribs.


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## mathesonequip (Jul 9, 2012)

if it gets real cold outside a 20 lb. cylinder will not deliver vapor fast enough, you will need a larger tank.


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## Ted n Ms (Apr 25, 2008)

mathesonequip said:


> if it gets real cold outside a 20 lb. cylinder will not deliver vapor fast enough, you will need a larger tank.



When i take off honey it's usally about 95. The bottle will be on the inside anyway.


I found one on craigs list that was 200.00 and when i looked it up It sold new for 729.00.
I also found a 30gal. tank heater that was 40.00 so i bought them both.


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## John R C (Mar 15, 2011)

Tankless heaters operate from 50,000-140,000btu for the small units. A small tank will freeze up even inside @ 90*. I recommend at least 120 gal tank.


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## John R C (Mar 15, 2011)

On second bought you just might be ble to get by with a 100lb tank.


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## Ted n Ms (Apr 25, 2008)

John R C said:


> Tankless heaters operate from 50,000-140,000btu for the small units. A small tank will freeze up even inside @ 90*. I recommend at least 120 gal tank.


John i am not following you. ( A small tank will freeze up even inside @ 90*. )
I will winterize this unit this fall.


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## Rader Sidetrack (Nov 30, 2011)

Propane in a tank is in a liquid state. But it only burns in the heating appliance as a GAS. In order to turn the liquid into a gas, so your heater will work, heat MUST be added to the liquid propane. (Its somewhat similar to turning water into steam.) Normally, the air surrounding the outside of the propane tank provides enough heat to warm the liquid propane into a gas, but if you try to take a lot of propane at once from a small tank, the air cannot transfer heat fast enough. That is why John recommended a larger tank.

Some more info on this issue: http://www.propane101.com/propaneregulatorfreezing.htm


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## Phoebee (Jan 29, 2014)

I run solar hot water, and just hooked up a single-tap point of use electric hot water heater as the backup hot water source. They are cheaper than gas, but my main reason for going electric is that it can work with pre-heated water. I don't think the gas ones can. I had to rig a bypass valve to get the backup heater out of the system when not in use, otherwise it restricts flow too much.

The reason for going with gas is that you don't have the power available (out in a honey house, etc) to run an electric. The little single tap unit uses 30 A 240 V, as much as a 40 gallon HWH! Whole house models may use 2 pairs of 60 A breakers!!! 

Be aware that you may need to install unions so you can pull the heater out in cold weather. My electric model has a U-shaped heating tube that traps water, and I expect most models, gas or electric, do the same. If they trap water, they'll suffer freeze damage.

Regarding liquifying propane, unless you're in the arctic, a propane tank used intermittently can usually hold pressure. Its when they run high flow for a long time that the pressure drops. There are a couple of pressure regulator ranges, with 15 psi being the higher range. A tank sitting at no flow can make 15 psi at around -20 F, but the pressure will fall off if you draw much gas for a long time. Larger tanks help overcome this. Tank heaters are available if you really need them, but running a hot water heater intermittently may not.

My generator uses 2 gph, for which we needed larger than a 125 gallon propane tank _if we ran continuously during the coldest weather_. But we actually close down during the coldest weather, and only run for 15 minutes at a time in any case. We get by with a couple of tall boy tanks.

Last December I was doing 5-minute runs with a 200,000 BTU/Hr propane torch, on a 20 lb cylinder, and about 32 F ambient air temperature, with an adjustable regulator set at 15 psi. Worked fine, and held pressure for that duration. Had I needed to run longer I might have needed to put the cylinder in a pail of lukewarm water.

Pressure versus temperature:

http://www.cdxetextbook.com/asearticles/propane.html


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## John R C (Mar 15, 2011)

Radar sidetrack is correct. The gas system(your propane tank and lines) have to be sized to the btus your going to need at the expected temperature. Propane has to evaporate to work. The evaporation process cools the tank and will cause condensation to freeze upon the outside. This insulates the tank and prevents it from warming quickly. This will limit the amount of gas the tank can produce. For example a 120 gal vertical tank at 20*f can only produce about 160,000btu of gas. At 75*f it produces about 340,000btu.


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## Phoebee (Jan 29, 2014)

John R C said:


> Radar sidetrack is correct. The gas system(your propane tank and lines) have to be sized to the btus your going to need at the expected temperature. Propane has to evaporate to work. The evaporation process cools the tank and will cause condensation to freeze upon the outside. This insulates the tank and prevents it from warming quickly. This will limit the amount of gas the tank can produce. For example a 120 gal vertical tank at 20*f can only produce about 160,000btu of gas. At 75*f it produces about 340,000btu.


Let's get our units straight here. The temperature of a tank of propane does not appreciably change the BTUs it can produce. It may very well reduce the _rate_ at which the tank can produce heat energy. We're talking BTU/unit time, usually BTU/hr.

Let's consider a Rheem RTGH 84, rated 8.4 GPM at 35 F temperature rise. Call it 8.3 pounds per gallon, I get around 146,000 BTU/Hr operated continuously. That's one of their smaller gas units, but that kind of flow is far higher than point of use, rated for 2-3 bathrooms. It is a high efficiency unit, probably taking about 161,000 BTU/Hr of gas to do that. But it won't take 161,000 BTU if you only need gas flow for 5 minutes. 

I can tell you from experience that a 200,000 BTU/Hr torch can run for 5 minutes on a 20 pound tank because I've done it. Did it get cold and the pressure dropped? Yeah, but the output of the regulator held a steady 15 psi. And I was running at 32 F. This user will be running summer temperatures. If he will be running a steady 8.4 GPM flow of hot water 35 F above the inlet temperature for an hour, well, yeah, he'll probably drain a 20 pound tank, much less freeze it. But running 5 minutes every now and then for cleaning? I'd worry more about total capacity needed than freezing up the tank.

A propane supplier can usually run the calculations, but you need to know the actual demand first before you state blankly that the tank is going to drop to no pressure output.

I have had it happen with a propane torch ... 15 F and unable to keep a robust flame going, but you'll rarely see it in the summertime.


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## Rader Sidetrack (Nov 30, 2011)

> steady 8.4 GPM flow of hot water 35 F above the inlet temperature for an hour

Typical 'hot' water is 120 degrees F or so. It seems likely that the temperature rise required to get 120 degree F hot water will be quite a bit more than a 35 degree rise. My unheated water is normally around 55 degrees or so. That would be about a 65 degree F rise required for 'hot' water.


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## mathesonequip (Jul 9, 2012)

residential hot water is 120 degrees at most [this is a federal law so little kids wont get burnt theoreticaly, are not our friends in Washington a big help?]. standard commercial temperatures are higher, in ny it is 150 for most of the food industry, minimum 165 degrees for dairy farms. this varies by state. I just got done putting an oil hot water heater in a pretzel factory a couple of hours ago I set it at 150. for honey house use 120 is not really hot enough, you may need to change the thermostat to get it hotter... yeah it was sunday night but I did get to buy some pint jars for 5 bucks a case.


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## Phoebee (Jan 29, 2014)

Rader Sidetrack said:


> > steady 8.4 GPM flow of hot water 35 F above the inlet temperature for an hour
> 
> Typical 'hot' water is 120 degrees F or so. It seems likely that the temperature rise required to get 120 degree F hot water will be quite a bit more than a 35 degree rise. My unheated water is normally around 55 degrees or so. That would be about a 65 degree F rise required for 'hot' water.


Yeah, but one degree F temperature rise in a pound of water is one BTU. Rheem was not giving me BTUs, but the data they gave let me calculate.

I know 120 F was the CPSC recommendation for hot water temperature to prevent scalding kids. I'm not so sure it is a federal law, although warning labels to that effect certainly are. I once did an investigation for a woman whose kids had been scalded by hot water in her apartment building ... the management had jacked the hot water up to 180 F rather than put in a properly sized hot water heater. 180 F will cook food, take the skin off adults. 

Point of use heaters offer a way to jack temperature up for specific needs such as dishwashing without scalding users at every sink.


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## mathesonequip (Jul 9, 2012)

phoebe our ground water temp. is 41 or 42 about the coldest in the continental us. ny has had the 120 residential code for years the feds have since adopted it. the ones who really like this are the lawers and judges. an alternative to point of use heaters is temperature control mixer facets.


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## Phoebee (Jan 29, 2014)

mathesonequip said:


> phoebe our ground water temp. is 41 or 42 about the coldest in the continental us. ny has had the 120 residential code for years the feds have since adopted it. the ones who really like this are the lawers and judges. an alternative to point of use heaters is temperature control mixer facets.


Yeah, but 8.4 GPM is a torrent from a single faucet. Most sinks these days also have a federally-mandated annoying flow restrictor and probably won't deliver more than about 1 GPM. At that flow the heater I specified could take in 41 F water and boil it, if not for the thermostat. All this is about balancing BTU/hr, flow, and temperature. 

The shower I took last night at the cabin was lovely. The solar hot water system still had 102 F in the tank in spite of a couple of cloudy, rainy days. The little single-fixture POU system had no problem raising the water to comfortable shower temperatures on a 1.1 GPM shower head.


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## KQ6AR (May 13, 2008)

I wouldn't recommend it if you intend to use it on a recirculating system to warm you're equipment it would run constantly.
A regular water heater cost about 1/3 the price, & savings between the two are minimal. The Renie's we have been installing at work only save the average household about $30 per year.


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## dp2k (Apr 22, 2012)

I've got one in my the "cottage" at the property where my bee-yard is - I love it! I was lucky enough to buy a HD "demo/floor model" for about 1/4 the normal cost, and install it myself which made the overall cost competitive with a conventional tank water heater. After 5 years of hot water showers on summer weekends, we've used 80 gallon of propane! (which causes a different problem, since now my propane supplier is charging me tank rental......). I believe till the cost of tankless + the high cost of installation and support come down, it will be equal (or close) to the operating cost of a tank water heater for most installations. I'm sold on the concept, but the economics aren't quite there yet. When (if) I ever build something new I'll keep tankless in mind in the water system design (all home runs for hot water, terminating near an exterior wall where a tankless unit could be vented). I believe it's the future, but like electric and hydrogen cars, the future isn't here yet for most of us.


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## Phoebee (Jan 29, 2014)

I looked at my generator propane consumption and said I needed a 125 gallon tank, based on maintaining pressure in cold weather. My gas supplier looked at the same numbers and said 250 gallons. Ten years later it finally dawned on them that we only run this 2 GPH generator a few hours a year, and we're not there in cold weather. They came and took the tank and left a pair of 100-pounders (about 46 gallons total). That was around 2000. In 2012 we finally emptied the first tank.

Yeah, at some point, if you're efficient with energy, you'll probably wind up renting the tank.


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## Country Roots (Jul 30, 2014)

Man... you guys sound like a bunch of engineers debating over a specific design decision... but I guess that's what you are doing. It's eerie how similar this discussion is to the ones I have at work. 

Good information though! Will have to keep all this filed away in case I ever get in over my head with bees...


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## Rader Sidetrack (Nov 30, 2011)

> Will have to keep all this filed away in case I ever get in over my head with bees...


Did you notice the thread TITLE? :scratch:

"tankless water heater" .... Why did you click on the thread in the first place?


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## cg3 (Jan 16, 2011)

mathesonequip said:


> if and when a tankless heater screws up it is a lot more expensive to repair. if you use it daily it is usualy quite dependable, siting unused for months is not helpful.


That's been our experience. Emphasis on "expensive".


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## Saltybee (Feb 9, 2012)

Looked at tankless when NG became available. Went high end tanks because warranties for the tankless I was selecting required a yearly acid wash. Before you jump on tankless check the warranty.
That would wipe out any $ or environmental savings.


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## dadux (Feb 23, 2012)

I went with tankless in the house to get rid of the chimney. No more warm house air wasted through the chimney. No more large amount of cold air drawn into the house. Love it!


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## Saltybee (Feb 9, 2012)

Hear you dadux. Power vent or hybrid models solve similar issues. Beekeeping is local, so are water heaters!


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## the kid (Nov 26, 2006)

We have a tankless for the main bath, which works very well. But for the kitchen sink, which is far enough away from the tankless that it takes forever to heat up
thats because it takes about 15 seconds to start after the water is turned on then it has to heat the water as it flows , so it takes a halfe min or more befor the water is warm ,then it has to flow through the pipe to the sink 
we had one for 7 years only thing that I have done to it is descaled it a few times ,,the only thing I have found wrong with thankless is kids can shower for an hour or two


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## Ted n Ms (Apr 25, 2008)

:banana: Update : Got my tankles water heater installed. I am using a 5gal tank to run it. Have all the hot water i need to clean up , wash hands etc. I think i am going to like it.:thumbsup:


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## Colino (May 28, 2013)

John R C said:


> On second bought you just might be ble to get by with a 100lb tank.


I bought a Bosche 14lts/min unit at home depot in Mazatlan Mexico and brought it home in a suitcase. It cost about $200.00. It has a standing pilot. It works very well off a 100lb propane tank and we use it in our concession trailer. Since we only work 5 weekends a year, in the off season I disconnect the propane and blow the water lines out so they don't freeze. I have been doing this for about 5 years now and no problems. It works on water flow and gives an unlimited amount of hot water. At the highest setting the water is hot enough to scald. I used it a couple of weeks ago to wash out our extractor, it gets hot enough to remove bees wax.
Colino


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## Buzzlightyear (Dec 4, 2013)

Im not sure if you are using in floor or forced air.

Some things to consider.
Short term use of in floor isn't very efficient because you have to heat up a lot of mass (cement) before it starts heating the room. Forced air would be a better choice. Floor would probly feel nice cool on the feet when extracting with forced air heat. If you use in floor heat it will be pretty toasty on the feet. Not a bad thing in the winter though.

All models I have looked at have no warantee when used as a floor heat, heat source.
My shop when I turn on the floor heat in the fall takes about 2 days straight running to warm up. Once its warm its prety much normal heat load but it takes most of a 100lb tank to get there and thats at 12c.


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## Ted n Ms (Apr 25, 2008)

Buzzlightyear said:


> Im not sure if you are using in floor or forced air.
> 
> Some things to consider.
> Short term use of in floor isn't very efficient because you have to heat up a lot of mass (cement) before it starts heating the room. Forced air would be a better choice. Floor would probly feel nice cool on the feet when extracting with forced air heat. If you use in floor heat it will be pretty toasty on the feet. Not a bad thing in the winter though.
> ...


Not sure what your talking about. My tankless water heater is mounted on the wall.:s


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## Buzzlightyear (Dec 4, 2013)

Ya most mount to the wall, but........
Where does your hot water go that heats your space?
Floor heat is most common, pipe in cement.
Forced air is next. Think heat exchanger with a fan.
Next is baseboard. Radiant heat.


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## Ted n Ms (Apr 25, 2008)

Buzzlightyear said:


> Ya mast mount to the wall, but........
> Where does your hot water go that heats your space?
> Floor heat is most common, pipe in cement.
> Forced air is next. Think heat exchanger with a fan.
> Next is baseboard. Radiant heat.


No need to heat space when it's 95 in the shade. I am heating water to clean up with. I am in Mississippi and have no need to heat my honey house.


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## Buzzlightyear (Dec 4, 2013)

Ya that makes more sense.
For some reason I thought you were heating your honey house.


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## Phoebee (Jan 29, 2014)

Buzzlightyear said:


> Ya that makes more sense.
> For some reason I thought you were heating your honey house.


I was kinda wondering where that came from. I use solar for heating a floor but sure would not bother in a honey house in late summer ... my panels are covered over and the system off.

If I were heating a floor, I'd not use a fast-heating POU heater. A small boiler or small conventional hot water heater is the usual approach. POU loses its advantage for space heating.


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## Buzzlightyear (Dec 4, 2013)

> If I were heating a floor, I'd not use a fast-heating POU heater. A small boiler or small conventional hot water heater is the usual approach. POU loses its advantage for space heating.


I guess we are discussing different situations hear but….

If you are talking heating water, it doesn't really mater the way, its the efficiency and cost. On demand are one of the most efficient ways but they are $$$$. What you are doing with that hot water may sway weather you go that rout or save your shekels for something else.
Im sure Ted will enjoy his new heater.
I don't think I would dish out the dollars for 6-7 days a year.
Maybe we are not talking the same type of heater. Cheep inefficient or expensive high efficient one.
For 6to7 seven days electric would suffice.
Take care 
Buzz


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## bugmeister (Feb 26, 2013)

How far are you from housed source hot water supply? Might be cost effective to by really good or really cheep couple hundred feet of garden hose- rig up a shut off in honey house and take it back inside in winter time?


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## ericweller (Jan 10, 2013)

Phoebee said:


> I looked at my generator propane consumption and said I needed a 125 gallon tank, based on maintaining pressure in cold weather. My gas supplier looked at the same numbers and said 250 gallons. Ten years later it finally dawned on them that we only run this 2 GPH generator a few hours a year, and we're not there in cold weather. They came and took the tank and left a pair of 100-pounders (about 46 gallons total). That was around 2000. In 2012 we finally emptied the first tank.
> 
> Yeah, at some point, if you're efficient with energy, you'll probably wind up renting the tank.


Phoebee,
What kind of propane generator do you have? My gasoline generator has burned me for the last time by not starting when I needed it. The mechanic said to switch to propane for more reliability. What is the wattage of your genny?

Thanks in advance!


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## Phoebee (Jan 29, 2014)

ericweller said:


> Phoebee,
> What kind of propane generator do you have? My gasoline generator has burned me for the last time by not starting when I needed it. The mechanic said to switch to propane for more reliability. What is the wattage of your genny?
> 
> Thanks in advance!


I've got a cranky old Onan 7.5JB (7.5 kW) with voltage regulator problems. I don't recommend it. Several of my friends have the tan ones that you get at Home Depot, and they're entirely pleased. They live in an area where the power goes out for days at a time.


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## mathesonequip (Jul 9, 2012)

when it gets down around freezing a propane engine is difficult to start. some of this answer depends on your location. it is not a matter of how much propane you use in a year it is a matter of delivery rate at a given time. the colder it is, the bigger the tank you need. I converted my fork-lift from propane to gasoline because of cold weather starting problems.


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