You're thinking about replacing your old water heater tank. Is it time to go tankless?
There's an endless supply of hot water, suppliers claim, since you only heat water when you turn your faucet on.
You can save room in your basement with a wall-mounted tankless unit and save money on your gas bill.
Kevin Kennedy installed a tankless water heater last fall after doing an energy audit of his four-year-old house. He's not impressed so far.
"It hasn't lived up to the hype I read in the papers, nor the sales pitch from the contractor," he told me. "The only savings have been the rental fees on the tank we removed."
A tankless water heater needs extra maintenance, he found. It has to be serviced once a year with a vinegar solution to keep it clean and functioning properly.
"Estimated cost is $100 a year – more than the gas savings."
He had to remove his water-saving shower heads, since there wasn't a strong enough flow to keep the water heater on.
"I now waste more water waiting for the hot water to arrive. It takes 10 to 15 seconds every time you turn on the tap for the hot water to get up to temperature – and up to a minute with the tap on full for the hot water to arrive on the second floor."
Reliance Home Comfort (formerly owned by Union Gas) tests tankless systems in its labs to simulate the water use of a typical family.
It finds you can save about 15 per cent of the energy previously consumed by the hot water tank.
A family of four with a 50-gallon tank spends $30 a month to heat water, says John Krill, director of operations support.
A 15 per cent gas saving means an extra $4.50 a month, or $54 a year.
That's not a big deal – and Krill agrees with Kennedy that the gas saving is often eaten up by the cost of extra water use.
"Many households take longer showers. From 10 minutes, they go to 12 minutes, knowing they won't run out of water. So, what happens to the savings? Zero."
You save energy only when you keep your hot water use the same as before, he emphasizes.
You may be disappointed with what you get when you need a trickle of water – say, to clean a razor blade while shaving. The cold water has to flow through the tankless unit and kick on a heating mechanism. This can take a while.
"Tankless systems won't give you the same hot water in a low-flow scenario as what you get from a storage tank," Krill says.
Second, there's the peak flow scenario when you want an endless flow of hot water. Again, you may be disappointed. A hot water tank uses about 40,000 BTUs of energy (British thermal units) but a tankless unit uses five times that, or 200,000 BTUs. "It fires up the burners and pounds the cold water to raise the temperature to 120 degrees Fahrenheit," he says.
The municipal water temperature is about 70F in summer, but can drop as low as 40F in winter.
The tankless unit has to work harder to heat water from 40F to 120F. This means your endless supply can run out in the cooler months.
So, scale back your expectations in winter. Instead of two showers and doing dishes at the same time, do the dishes later.
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