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Depending on the model, tankless water heaters can be installed inside or outside the home. Photos (left to right): omiksemaj, Flickr; tom.arthur, Flickr

All those steamy hot showers you enjoy so much? They're costing you big-time. Hot water is the US consumer's third largest energy expense, accounting for around 12% of the average utility bill. A water heater upgrade is one way to cut costs. But it also leads to the question of whether to replace it with another traditional storage tank heater, or to opt for a tankless water heater. Should you or shouldn't you?

HOW DO TANKLESS WATER HEATERS WORK?
Let's take a closer look at water heaters.

Storage tank water heaterA conventional storage tank water heater. Photo: Vagabond Shutterbug, Flickr

A conventional water heater draws hot water from a thermostatically-controlled storage tank that refills automatically. The entire tank of hot water is held on standby 24/7. A lot of energy is gobbled up keeping the temperature constant, replacing hot water you've used and compensating for heat lost to the surrounding environment.

A tankless heater, on the other hand, conserves energy because it doesn't keep hot water in reserve. Instead, water is heated on an as-needed basis, routed through a powerful heating unit whenever a hot water faucet is turned on. Typically gas-fired (although you can buy electric versions, too), tankless heaters depend on electronic sensors to detect and regulate water temperature and flow.

BENEFITS OF TANKLESS WATER HEATERS

When it comes to space efficiency, energy efficiency, and durability, tankless water heaters can't be beat.

Tankless heaters are appealingly space-efficient, consisting of just a compact rectangular unit attached to the wall. Compare that to storage tank heaters, which typically hold 20 to 80 gallons of water. For homeowners with space limitations, tankless just makes more sense.

Then there's the obvious energy savings. Tankless water heaters are getting lots of buzz these days, in large part because many now boast the coveted blue ENERGY STAR sticker, which indicates that the product meets strict energy-efficiency standards set by the government. Because they only heat water on an as-needed basis, monthly heating bills are usually lower.

Manufacturers claim a much longer lifespan for tankless heaters: over 20 years compared with just 10 years for typical storage water heaters. That's because tankless heaters contain replaceable parts that can be repaired when a problem occurs; storage heaters often must be trashed after a breakdown. For that reason, it's also fair to say that tankless heaters are more environmentally friendly, since they reduce landfill waste.

DRAWBACKS OF TANKLESS WATER HEATERS
The main downsides of tankless water heaters are cost, installation, and maintenance.

Tankless water heaters cost a lot more than storage tank water heaters up front.
Gas-powered tankless units range from a couple hundred to $1300, compared to standard tank heaters, which are generally in the $150 to $500 range.

Installation is also more complicated and expensive for tankless than for tank heaters. Electrical outlets have to be installed to handle the unit's fan and thermostat. A gas supply line and venting system are usually required, too. Plus, you have to spend around $1000 or more on installation, compared with just a few hundred dollars for storage tank heaters. Some tankless water heaters can be installed on the inside or outside of the house.

Tankless heaters should be serviced about once a year to remove calcium buildup. Exactly how often this servicing is required depends on water hardness levels in your town; harder water causes more calcium buildup.

Another Upside: Rebates and Tax Credits
More good news: the government wants you to invest in energy-efficient home improvements, so numerous rebates and tax credits have popped up to offset the price of purchase and installation.

Rebates:
Now is actually the perfect time to buy, since state-by-state rebates are finally coming into effect. Interested? Check out this list of rebate kickoff dates by state.

Tax credits: You may also be eligible for a Federal Stimulus Package tax credit. This trims 30% off the price of certain ENERGY STAR-rated tankless heating units, awarding you up to a maximum of $1500 off total purchase and installation costs. For more details on rebates and tax credits, visit the Noritz and Takagi websites. Check manufacturer sites, including those for Rheem and Bosch, for listings of which tankless water heater models qualify for government assistance.

Be sure to bookmark these two essential Web resources, too: the Database of State Incentives for Renewables & Efficiency, which provides a comprehensive list of tax rebates available to consumers on a state-by-state basis, and the US Department of Energy's ENERGY STAR Approved Energy Efficient Appliance Rebate System info page.

TANKLESS WATER HEATER CONSIDERATIONS

Brand: If you do decide to upgrade to a tankless water heater, do some research to find the brand that's right for you. Big-name manufacturers include Takagi and Noritz, as well as more familiar household brands like Rheem and Bosch.

Size: You'll also need to choose the right size tankless heater for your home and region. This is often calculated in terms of gallons per minute (gpm) that a given heater can produce. This can get complicated, since the gpm ratio depends, in part, on ground temperature relative to your required water temperature.

Your location: Tankless heaters draw and heat water directly from the public water supply. One tankless heater may cost X dollars per month to operate in a mild Southern winter. However, that exact same heater would cost a whole lot more in a freezing Northern winter simply because it is drawing upon much colder groundwater.

TANKLESS WATER HEATER QUIRKS

The heating mechanism must sense a minimum water flow before kicking into operation. If you like to conserve water and energy by using just a slow trickle of hot water for certain tasks (such as shaving), you may be out of luck. It's the full flow or nothing.

Because tankless heaters depend on electric controls and there's no backup reserve water, you will lose hot water during extended power outages. That may not happen very often, but it's definitely something to be aware of.

You won't get instant hot water from a tankless heater.
Just as with a storage tank heater, you must run the hot water faucet to rid the pipes of cold water before the hot water starts flowing.

A final word of advice: Unless your existing water heater is on its last legs and absolutely must be replaced, there's no urgency to switch to a tankless version. If lowering your utility bill is your primary concern, there are lots of ways you and your family can spend less on hot water this winter. Check out this page of energy-saving tips from the US Department of Energy to get started saving!

See also:
How to Install a Propane Tankless Water Heater
Water Heaters Have Gone Hybrid


  • Lee

    here in the earthquake state of California, I am glad to have a regular old fashion water heater. during the Northridge quake, the electricity came back on in a couple of days, but the water was not running for a week or two in some areas of the San Fernando Valley. we were able to drain water from our water heater for use! Also, during a recent blackout, we had hot water for showers. our neighbor didn't.

    Reply
  • john

    had my neighbor do simple preliminary work and only neded 60 amp breaker. i did the tie in for him. no permit is required if you do the job.there are 4 15 amp breakers in unit and only operates zones according to usage.don't know unit cost but material was less than $75.00

    Reply
  • Betty

    We've had our unit for almost 2 years. We had to replace our pipes and we got a pretty good deal on going tankless with the Noritz. We also had a water softener put in and controls at all the sinks that make it so we get instant hot water. One of the biggest benefits from the system is we can attach a hose to the bathroom sink, run it out the window and refill or top off our spa and not have to spend hours heating it up. We love it.

    Reply
  • tim

    I have been working with Navian tankless water heaters.
    Navian has stainless steel tanks and burner units.
    It has 98% effiecency and the exhaust line is PVC, cool.
    I am pleased with the units. My only problem is I did not know a washer used 8 gpm. but that can be repaired.

    Reply
  • William

    I agree with what Diane stated in his post . i have read a lot of
    tankless water heater reviews . it is also a great way to reduce monthly bills. and i highly recommend rinnai tankless water heater it is the best tankless water heater in tankless water heaters market

    Reply
  • 45 Comments / 3 Pages

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