March 23, 2017 | Miles Durie

Getting in hot water

New water heater technology and incentives are making tankless systems feasible for more Calgarians

here's nothing better than being in plenty of hot water. Not the metaphorical kind, the real stuff. If you've ever felt the shower go cold while you're still covered with soap and shampoo, you know what I mean.

But new water heater technology is helping reduce the likelihood you'll run out of the hot stuff, while providing environmental and money-saving benefits.

Water heaters are a big financial drain, sucking up almost 20 per cent of the energy used by the average Canadian household, second only to home heating. Obviously, reducing that number is a good thing, and new building codes are pushing in that direction, says Stuart Rudolph, president of Rudolph Plumbing & Heating Inc. in Calgary.

"I'm seeing an increasing number of tankless water heaters, but also power direct-vented tank-type models as well," said Rudolph. Both of these are coming into play because of new furnaces codes that eliminate the conventional chimney in recently built homes, he says.

"Since only high-efficiency furnaces with their PVC (plastic) exhausts are available, homebuilders haven't needed to install conventional metal chimneys for about a decade, so we're seeing more high-efficiency water heating options due to the absence of chimneys in newer homes," he said.

Power direct-vented natural gas water heaters employ a fan to drive combustion gases out though a PVC exhaust pipe, and the lack of a chimney tube running up the middle of the tank eliminates a significant source of heat loss, Rudolph says.

I'm seeing an increasing number of tankless water heaters, but also power direct-vented tank-type models as well.

"Smaller amounts of standby loss are experienced through a tank's insulation jacket, but the chimney in a conventional heater is by far the main culprit."

Great, but what about those tankless, or on-demand, heaters? Doesn't it make the most sense to heat water only when you need it, instead of keeping a big tankful hot and ready? They look good on paper, but Rudolph says in the real world they bring some extra complications, especially here in Calgary, where our mildly hard water can cause mineral buildup in the heaters' small passages, restricting their flow capacity.

"To operate safely, tankless heaters have sensitive switches that will prevent their burners from firing if they have inadequate water volume running through them. This means they must either be descaled on a preventive maintenance schedule, or have a water softener installed upstream of them."

Interestingly, the Alberta government's energy efficiency program will soon offer incentives to buy tankless water heaters, so sellers of water softeners may soon see a boost in business as well.

So, if your home, or one you're considering buying, has a conventional water heater that's nearing the end of its life – usually 12 to 18 years – what should you do?

"The main questions I'll pose to a client are the number of people in their household and if there is a unique demand, such as a larger-than-normal bathtub," said Rudolph.

"I've been to a few new homes where the upgraded ensuite bathtubs that were selected couldn't be filled properly by the smaller-capacity water heaters that were installed. So with tank-type heaters, take note of their storage capacity, but also pay attention to their BTU (British thermal unit) input and recovery capacity."

Properly installed and maintained, tankless heaters can fill any size tub, since they just keep on delivering, but some models might not work fast enough to support multiple fixtures running simultaneously, he says.

If you're thinking about going tankless, Rudolph's advice is to stick with a well-known, established brand.

"Having a lesser brand that stops making repair parts after a few years can be frustrating."

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