Anyone here have a tankless water heater?

[Ibanez]

Opinions?

I'm thinking of putting one large one and up to two smaller point of use ones in the new house my wife and I are going to start building in the next three to six months.

[Conan71]

Do it.  It will pay for the difference in cost from a tank heater in a couple of years or less.  If NG gets higher, the payback is that much quicker.  Why heat water during the day or middle of the night when it's not needed?  Not only are tankless more efficient from a heat transfer stand-point, you no longer have radiant heat loss.

We rep for a company which makes condensing tankless water heaters for commercial applications.  99% efficient, much higher recovery rating at a 100 degree rise.  Our customers are a little slow coming around to this technology, but it's starting to happen.

If you are building a new house, you might even consider going to hot-water radiant flooring or base board heat, much more efficient than scorched air.  There are a couple of mechanical contractors in town I'd recommend if you are interested in looking into it.  I'm not putting in a plug for my own business, as we don't do anything residential.

[Ibanez]

I'm really leaning toward the tankless. Not only for my costs, but to also keep my use of energy down for environmental purposes. The less fuel I have to use the better for everyone.

Any recommendations you can give would be greatly appreciated.

Thanks!

[Conan71]

If you are interested in progressive thinking and a very, very good reputation around town, call K & M Shillingford for your mechanical needs (heating/air, and a tankless).  Not the cheapest, but you will see a good payback in dealing with them.  I've had various business dealings with them over the years and they are a very good outfit.

Air Comfort out in Jenks is another very good mechanical contractor and also gets into some of the same technology as KMS.  I don't think you'd go wrong with either company.

[rwarn17588]

Conan, you seem to have a good grip on these devices.

Do you have to replace the pipes in your house if you're retrofitting these tankless water heaters? And is the ventilation for them a pain to install?

That's what's been holding us back from making the jump, plus our in-laws have one (a Bosch, I believe) that doesn't work very well.

[stymied]

Be careful of KMS.

Any licensed plumber can install a tankless.

Before you decide, have an electrician perform a load calculation with the tankless added.  You would be surprised at how much electricity is required.  Most require at least one 50 amp circuit, some 2.  If you are thinking of adding one primary tankless and 2 on demand you could commit more than 100 amps of electicity to heating your water.  Don't know what size your panel is currently, but before you know it you could be upgrading your electrical service.

[AMP]

I have experienced the Bosch unit.  Lots of negative posts on forums regarding the tankless systems.  

My friends leaked before a year, it has a seal and valve that need replacing every year. Piece of crap in my opinion, but their web site had the kit to repair it.  

On This Old House they use a circulation pump that brings hot water to the faucet needed by using a motion detector which runs the pump whenever someone is near the faucet.

Hard to get the throttle adjusted lean or rich hot water when you first start using one.  Not really the best deal for the shower, but other than a 500 gallon tank, what is?

Install is easy, he and a few of my other friends have installed all their by themselves with simple hand tools.  They can be mounted in walls, cabinets and even in the attic.  One my friend has is gas fired.  

Enjoy reading the comments...

http://www.epinions.com/Bosch_AquaStar_125B_NG_Natural_Gas_Tankless_Water_Heater/display_~reviews

[OurTulsa]

I don't have much experience with them but looked into installing and found many positives.  Here is another incentive to install a tankless: a one time federal tax credit.  Check with your vendor because the unit has to meet efficiency standards.

Tankless Water Heater
Tax Credit Guidelines
From the Energy Tax Incentive Act of 2005

Personal Energy Credits for Non-business Use
1313. Nonbusiness Energy Property Credit. A tax credit is available to individuals for the installation of nonbusiness energy property,
such as residential exterior doors and windows, insulation, heat pumps, furnaces, central air conditioners and water heaters (Code Sec. 25C, as added by the Energy Tax Incentives Act of 2005 (P.L. 109-58)). The credit is equal to the taxpayer's: (1) residential energy property expenditures plus (2) 10 percent of the cost of
qualified energy efficiency improvements. The credit is limited to a lifetime maximum of $500 and no more than: $200 of the credit can be based on expenditures for windows; $50 of the credit on any advanced main air circulating fans; $150 of the credit on any qualified natural gas, propane, or oil furnace or hot water boiler, and $300 of the credit on any item of energy-efficient building property.
The credit applies to qualified energy efficiency improvements and qualified energy property placed in service in 2006 and 2007. The
property must be installed in, or on a dwelling unit in the United States that is owned and used by the taxpayer as the taxpayer's principal residence and originally placed in service by the taxpayer. Residential, energy property expenditures (heat pumps, furnaces, central air conditioners and water heaters) may include labor costs.

[Breadburner]

Tankless units work great....Two of the best are Paloma and Takagi..Both are used widely in my industry....I Would stick with natural gas if at all possible...

[moosedaddy]

I have had an electric tankless for about 1 year and would never switch back to a tank.  The only draw back to the electric is that they are only good for 1 major use at a time.  There are 6 of us in our house and we never run out of hot water.

My unit is a Powerstar (Bosch) and runs off of 3 40 amp 220V breakers. I wish I could have put in a gas unit but our house is total electric, the tankless still saves us about $20 a month.

My tankless unit came with a 10 year warranty and I was told they are designed to last 20 years.

[Conan71]

quote:Originally posted by rwarn17588

Conan, you seem to have a good grip on these devices.

Do you have to replace the pipes in your house if you're retrofitting these tankless water heaters? And is the ventilation for them a pain to install?

That's what's been holding us back from making the jump, plus our in-laws have one (a Bosch, I believe) that doesn't work very well.

RW- I don't think you would have to re-pipe on a residential.  My entire experience with these is with commercial gas-fired.  Apartment complexes and office buildings need a recirculating loop or recirculating storage tank in order for them to work properly.  So far as I know all that's required is a flow switch on the hot water line for a residential application.

Ventilation isn't a big deal, the particular brand we represent (they go from 45K to 199K Btus per hour) are so efficient that the recommended material for the vent is CPVC pipe since the vent temp is about 110 to 120 deg. F.  Now that's efficient.  You do have to install a condensate drain because the heating coil condenses with the low inlet water temp.  It's also very low emissions, about 9ppm NOx.  However, these units are not overly practical for a home user, unit cost is about $3000 to $4000 plus installation.

I'm not a fan of electric heating appliances so far as reliability and durability.  I've not had great luck with them, and it might just be my poor luck not anything inherently wrong with them.

[sauerkraut]

Yes indeed, I favor these things. I wish all new homes would have them as standard equipment. They are hard to install or retro-fit alot of gas line work and venting and electrical wiring is needed if you don't have one currently. I don't know why there's not more of these things in homes I think to save fuel you can't beat them plus the hot water supply is endless, as long as the burner is on hot water is flowing. They also last far longer that a regular water heater.

[cannon_fodder]

As a side note, using electricity as a heat source is horribly inefficient.  A power plant has something like a 36% efficiency (of the total energy in a ton of coal, 36% is converted to electricity), backing out the high energy required to produce coal and transport it to Tulsa that number drops to near 30%.  Line loss is then another 7%.  A tank less water heater is around 85% efficient (some are in the 90s now).

Running the math:  .30*(1-.07)*(1-.85) = 25%

So for overall ENERGY USAGE, a tank less electrical water heater ends up at 25%.

Gas, on the other hand, has a much lower transportation cost and next to no conversion loss.  All in maybe 5%.  Getting a 85% efficient heater is then actually 81% efficient.  Thus, even with the heat loss from the sitting tank the overall energy efficiency is still probably better.  However, with coal being super cheap in the USA electrical tanks probably DO save money.


Just wanted to point out the horrible inefficiencies of electrical generation.  Everyone seems to think electrical power is the perfect solution.  In reality, it is horribly inefficient. It is able to achieve cost reductions via an economy of scale and the utilization of the cheapest available commodity - which consumers essentially cant utilize - and thus is often more economical than other forms of energy.

[Conan71]

CF- Depends on which efficiency you are talking about.

Be careful about confusing combustion efficiency with thermal efficiency or economic efficency, or operational efficiency.  Most power plant boilers with stack-gas economizers and condensate economizers (virtually all U.S. plants are so equipped) will get an average of about 80 to 85% thermal efficiency.

You might be referring to low economic efficiency when getting the 36% figure, based on mining/production, transportation, crushing, etc.  

As a matter of economic efficiencies, only wind, hydro, and solar are cheaper than coal, even with the mining, transportation, storage, and preparation costs.

The majority of electricity on the Tulsa grid comes from either hydro-electric or gas-fired plants.  AEP/PSO estimates only about 30 to 40% of their capacity comes from coal-fired plants.

[patric]

I put in an Bosch Aquastar I got from Lowes two years ago and consider it one of the better investments weve made.

A bad experience with an electric model at a place I stayed at left me leery of tankless, but the gas versions are as different as night and day.

We did have to increase the size of the vent pipe but that was not that big a deal.  Basically, with tankless you are quickly heating  your water as you use it rather than cooking it 24/7 as you would with a tank.

The only complaint we had was that when there are a string of very cold days the incoming water is so cold that the 40-degrees the tankless unit raises the temperature to sometimes isnt as hot as desirable, but weve never missed a shower or clothes washing because of that minor inconvenience.      

Of course you never run out of hot water -- which might be a downside if you had been using the temperature shift of a depleting tank to time your showers. []

On the upside, we rarely run appliances when we shower so it's never a problem, the small size of the heater gave us some new closet space, and we still have a source of emergency warmth for when the power fails.