Propane Tankless Water Heater (Home Use)

Dennis,
Nobody has mentioned recovery rate which should be a key consideration. The tankless units have in effect an almost unlimited recovery rate but cost more and depending on the length of pipe run can cause some delay in delivering hot water to the tap. I took a different option and installed a 25 gallon Bradford White high recovery rate unit (83,000 Btu/hr) and never ran out of hot water. The unit cost around $1,100 or so installed. With the small tank, we could keep it at a much higher temperatue since there was a cold water cross-over to prevent scaulding. It was a gas unit but I am sure they could put smaller orifices on it to convert to higher heat content propane. There may be other brands besides BW that offer this type of unit but I can vouch for them. My new house has a 75 gallon propane unit that does not perform as well or as cheaply as the BW unit in my old house.
 
You can't legally convert a water heater except in a mobil. They are labeled for nat gas or lp gas only. But All the major mfg make high recovery units the only thing you need to be concerned with is the gas pipe sizing. And yes this is a good alternative.
 
stevea661 said:
You can't legally convert a water heater except in a mobil. They are labeled for nat gas or lp gas only. But All the major mfg make high recovery units the only thing you need to be concerned with is the gas pipe sizing. And yes this is a good alternative.
Click to expand...

It may be illegal in CA but that is not necessarily the case elsewhere. However it involves changing more than just the orifice which my previous post didn't point out properly. But I agree with you it would be better if to get one that was set up from the factory.
 
Hello
i own a mechanical company and have been master plumber for 30 years to give you alittle back ground. On demand hot water heaters have their applications but are limited depending on incoming water temp from the utility or well also they require a lot of fuel most are around 199000 btu input at full demand and are warranted for 12 year s on heat exchanger so my feelings are if you have the space use a regular water heAter the Effiency of the on demand drop. As usage goes up since it takes so much energy to flash heat 45 degree water to 120 degree instantly. Also as you incoming water temp falls in winter your gpm at your target temp will drop since most units are rated at 50 to 55 degree water with a 60 to 70 degree delta which is the amount it can raise the temp of the incoming water. So that being said we use ondemand water heaters in certain applications usually deticated for a master bath in a McMansion with the hot tub body washers and large hot water demand then we use a smaller heater for remaing house because most clients use that big hot tub once and awhile so keeping an additional 80 gallons hot for the twice a year doesn't make sense the second would be small cape like house with elderly and. No children where hot water demand is minimal third would be a home with limited space for storage type. They do require more maintenance they are no different them a tankless on a boiler if the water is hard they will scale and lime up.

So that being said the best manufactures are Akagie Rinnia then Bosch I hope this helps and the average Gpm at 120 degrees is around 3.5 to4.5 gallons per minute which is two showers or laundry and shower these numbers are at brand new and do change with time and water temp as flow rate increases the flow at fixtures decreases. If you have more questions let me know. Some guys swear by these things others aren't I just deal with what I know from putting them in and also tearing them out. Good Luck
 
This is all great information and I'm taking it all in. Thank you all for taking the time to respond.

My propane company just came back with an estimate... $3,700 for a Rinnai RC80i. This includes running about 20' of gas line and 25' of venting. Both would be run in the ceiling of an unfinished basement. Unless I'm missing something, that seems to be high. I did some VERY quick googling and calculations and came up with about $1,700-$2,000 in parts (the estimate from my propane company wasn't broken down). But again, maybe I'm missing something.

I'm going to keep checking and thinking. In the meantime (using the little 30g electric tank), it's at least giving some members of my family a rude awakening on water conservation.
 
Hello
What you have to remember is they are not giving you materials at cost they are in the business to make money and they are going to have to warranty it $3700 is a fair price her in Mass and NH it runs $4000 to $4500 due to code issues also you need to have and electrician for theses units since they require power the unit at contractors cost is about $1200 with venting materials then another $150 to $250 for electrician then probably $400 in misc materials may be a bit less then 6 to 8 hours of labor including inspections the average service business needs to make $1100 to $1500 per day per truck and single man to stay viable here in the north east I'm not sure about PA
 
I agree - I understand that a business needs to make money and I fully support that. What I don't know about is what you are referring to and that is what they "need" to make. If this does turn out to be a fair price, that's fine - in that case, it is what it is. With my initial intentions, though, this will be more than I wanted to spend on this project. I'm not pulling the plug just yet, though.
 
WI completely understand did they explain the gpm they expect you to get. The dollar amount I spoke of is before their expenses they don't actually make that much if we did I'd be retired 15 year ago lol. The 80i unit will do about 4 gpm @ 125 degrees with in incoming water temp around 45 degrees if you do proceed just make sure that will good for you summer time you'll get alittle more.
Good luck
 
I didn't talk to them directly/specifically about the flow. The gentleman that came over for the estimate stated that he will size the unit based on my house and number of fixtures, as opposed to how many people are currently living in my house. His reasoning was that if we sell the house down the road he wants the unit to function properly, even if there ends up being more people living in the house. He said "It's our name going on the unit and we don't want someone associating mediocreness with us". His comment, coupled with the research I did (I have 55* incoming water temp in the dead of winter), leaves me feeling comfortable that the unit would be sufficient.
 
With the lowest water temp at 55 you should be fine I get 40 degree water in the winter some times lower I'm on well so it's not an option for me.

Good luck with it if you pull the trigger.
 
Thank you - I appreciate the info you gave.
 
Mainstream is spot on in all respects. The only two things I would add is if you soften the water into the heater your maintenance will be greatly reduced, I have soft water and like the shoe maker with no shoes I waited 6 years to de scale. The mfg rec is six months to a year and my unit was clean, In other words it didn't need a cleaning :grin: . The other thing is don't buy a Bosch. I've been hands on for 35 years and they're a POS, IMO.
 
Good to know about Bosch. I do have a softener and have heard/read about the vinegar/descaling thing. Thanks!
 
Dennis,
What is the price of propane in your area. Here in AZ I am paying $3/gal which makes it on an equivalent heating basis more expensive than my $0.09/kwh electricity. I live in the sticks where there is no natural gas service so propane dealers only have to compete with electricity. The house came with a 75 gal. propane water heater which I may replace with an electric one in the future. Hopefully the propane price is cheaper where you live since they most like have to compete with fuel oil on an equivalent heating basis. Regardless of whether you go with a tankless unit or not, my additional advice is to check out the on going fuel costs along with the installed price of the unit.
 
Hello
most propane companies have a couple price tiers residential low use which is hot water and cooking the residential heating the more you use the less you pay I pay $2.48 per gallon where low use pays almost a dollar more. I don't know if its the same where you are.
 
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