Rinnai versus Takagi.... tankless water heater

I've been looking into these brands of tankless water heaters......I know there are more and am open to consider other brands. A little background: Right now I have a two year old electric water heater. I'm having trouble figuring out how much this thing is costing me. I'm assuming it's anywhere between $35 -$55/month. My electric bill fluctuates between $125 and $175 a month (winter months being more). My last bill was $150 and I used 988 KWH. That comes out to $0.15/KWH. I heat with wood in the basement to warm the floors and a Rinnai Direct Vent heater in the main living area. So, an LP gas ($1.80/gal) unit would be easy to get going. (Although I have seen those SETS electric tankless. They claim a 98% efficiency).
Rinnai's website has a little flash program that allows you go calculate savings. Over 20 years, with my set up, I'll be saving $21,000. Of course, that's best case scenario and assumes a number of variables remain constant. But even if it's half that it would be worth it. '
Takagi brand seems a bit cheaper (Rinnai installed is $2000 with $500 of that being labor).....have yet to get a Takagi installation quote. Although, I could install these things myself......but that voids the warranty....correct? ROI seems to even out at the 2-3 year mark according to their numbers.
Some, however, are sticking with their electric water heaters.
I guess I'm wondering what anyone who has gone through this process thinks? It seems to be a logical choice to go tankless, but I've read of those who were very sorry.
And on the Rinnai vs. Takagi comparison.......what do you think of that..........
Thanks for your time and any opinions.
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We should create a FAQ for tankless.....
The issues are first the cost to convert. Figure for electric a new service entrance dedicated to just heating water, at least a 100 amp but probably 200 amp plus regular service for everything else.
it takes a LOT of power to instaneously heat water...
If you go LP figure in a much larger tank and lines upgrade. again it takes a lot of gas to instaneously heat water. natural gas will likely require larger gas lines and perhaps a new meter for higher flow.
the only energy you waste with a regular gas or electric tank is standby losses in summer. in winter standby loses help heat your home, so the energy isnt really wasted.
its soiunds great to never run out of hot water:) some folks like teenagers use that as a excuse to take endless showers increasing energy bills:(
on low flow say cracking a valve open to wash hands the flow may be below the minimum to trip it on, so cold hand washing
check carefully the flow vs temp rise. in summer it may not matter but say cold winter water temps may leave you never really hot enough when showering.........
If you have a good supply of LP upgrading to that for water heating is probably a good idea using a standard hot water tank.
the tankless although liked by some have lots of negatives and the payback or savings will likely exceed the life of the unit.
to save energy add a insulating blanket to your existing tank.
to never run out of hot water series connect your existing electric tank with a new LP one, electric first. at times of high demands power on electric tank ands enjoy nearly endless showers.
My current tank is 75,000 BTU 50 gallons natural gas, Installed in 2000 I rarely run out of hot water. I wouldf of gone 75 gallons but it wouldnt fit:(
i hate cold showers
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forgot to mention, in a power failure a tankless means no hot water, even a LP tankless usually need electric so no hot water. with a tank type at least you have a tankfull for quick shower etc.
incidently newer tanks have low standby losses. a old gas one leaked years ago. I turned it off, then back on the next morning so I could get a shower. water was still nice and hot
nice site about water heating
http://homeenergy.org/archive/hem.dis.anl.gov/eehem/96/960510.html
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I was going to do it, and have changed my mind. Mainly it is lifestyle, not cost of installation that has put me off the idea. We are home all day and night, so in our case the savings would be minimal. For someone who is out as much as they are home the savings in standby losses might be more. There is also the noise factor, a jet taking off every hand wash would be a little upsetting. So I'm going to soldier along on the units I have and think about solar.
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The other thing I forgot to mention was the time it takes to get that hot water to the upstairs. It's about 20-25 feet of 1/2" copper that would be filled with cold water..........
Thanks for all the info/insight. It's difficult to decide. I was reading that the Takagi can also handle radiant floor heating which would be an interesting thing. I start to figure that if I'm going to be spening around $2000-2500....how better could the money be spent. My wife wants to retro fit the house with a boiler and hot water baseboard. But that is getting into the $5000-7000 range. Radiant seems a possibility as the new LP gas tankless would be used for both hot water and the radiant system -- I think this could be done or would it have to be an "either or" situation.
On the other hand.....I could just get used to cold showers. I asked my wife if we could turn off the hot water heater for a week so that I could calculate how much energy it used. She looked at me with a look I've never seen before then said, "Yeah right..."
Eric in North TX wrote:

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Also....check out this new technology:
http://www.pulsaradvancedtechnologies.com /
Instant hot water using Microwaves.
bradah wrote:

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