Cottage Q&A: Tankless water heaters in cold temperatures

A tankless hot water heater mounted to a white wall By KenSoftTH/Shutterstock

We need to replace the hot water tank at our cottage near Burk’s Falls, Ont. We are interested in tankless-style water heaters, but we wonder if they will get the water warm enough. We use the cottage mostly in spring, summer, and fall, but do make one or two trips there in winter. Our heat is electric, and we are not interested in installing propane. Will the tankless models perform well this far north?—Sue Tereschyn, Middle Doe Lake, Ont.

Our sources say no. That sounds like we asked a Magic 8 Ball, but we asked real people.  

“Burk’s Falls is cold,” says Paddy Wright-Harris, the business development manager at Muskoka’s Harris Plumbing. “The incoming water temperature—depending on the source—will be super cold,” she says. “The unit may not be able to reach 120 degrees output.”

Matt Girard, the owner of M&J Plumbing in Peterborough, Ont., says that in rural areas, it’s often the water quality that’s the bigger issue—and that could be a problem year-round. 

Tankless heaters can be fussy: hard water, sediment, iron, or anything else in the lake or well has the potential to clog and damage the tubing inside the unit. So this could mean installing a water softener and/or a filtration system if you don’t already have them. Ka-ching.

Plus, says Devin Klatt, a plumber with Harris Plumbing, not all cottages are going to be wired for a tankless heater. “Some units require three separate, dedicated 50-amp breakers and a main service panel of at least 300 amps,” he says. It’s possible your cottage has all this juice, but we suspect not. (Even most average homes only have a total capacity of 200 amps, says Klatt.) So you’d need to make some electrical upgrades. Ka-ching.

We don’t want to knock electric, tankless hot water heaters. They have a lot of pros. And drained and properly winterized, they can survive the winter just fine. Baby them, and they can last up to 25 years. But if not, the repairs or replacement parts can be costly, says Klatt. So, yeah. Ka-ching.

Happily, new electric hot water heaters come in space-saving designs, they’re better at keeping water hot, and they’re more energy efficient. Shop around. Look for a model with a long warranty and have it serviced regularly, says Wright-Harris. “That would be a safer bet, and our professional recommendation.”

This article was originally published in the Winter 2021 issue of Cottage Life magazine.

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