A Reddit warning thread left one Wisconsin homeowner worried that a roofer's decision to swap a large roof vent above the water heater for a much smaller cap may have created a dangerous exhaust issue — and left the home without hot water.
Here's what to know
In a Reddit post, the homeowner said the roofer insisted the replacement was acceptable, prompting them to ask whether the setup was safe.
The original poster wrote, "I turned off the water heater and we've been without hot water all weekend. Pregnant wife isn't happy."
Most replies said the installation did not look right.
One commenter identified the replacement part directly, writing, "That's a Broan 636 roof cap. These are made for ventilation but not for water heater exhaust."
That same commenter added, "Any roof cap used for a gas-fired appliance such as water heaters and furnaces must be vented using double-wall B-vent."
Another commenter was even more direct: "Rating=1. Wrong exhaust setup for a water heater. That vent cap is normally used for bathroom exhaust fans."
One more also rejected the roofer's explanation, warning, "If the flue gas cannot go out … well it can only go back in. Big safety violation."
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For homeowners dealing with a water-heater issue, replacing an aging unit with a heat pump water heater can save on utility bills while avoiding the venting complications that come with gas-fired equipment.
More background
This kind of venting depends on the right termination, clearance, and materials to keep the water heater drafting properly.
"The way the vent is currently set up is a big No-No," one commenter wrote. "The National Fuel Gas code states that the vent must terminate 2 ft higher than anything within 10 ft around it. It is required for proper drafting."
Because the new cap sat so close to the roof, one commenter warned it could end up blocked by snow or by condensation that froze over the opening. Another noted that the previous setup may not have been fully correct either.
Several replies said the smaller gooseneck-style cap looked appropriate for attic or bathroom ventilation, not for venting exhaust from a gas water heater.
If you want to avoid all of this with your next water heater, Cala makes customizable smart heat pump water heaters that help homeowners lower their energy bills by heating water exactly when it's needed. Because they are heat pump systems rather than gas-burning units, they also avoid the kind of roof-vent configuration problem that sparked this family's scare.
That smart scheduling can be especially helpful for households with changing routines or heavy hot-water demand, since the system matches heating to usage instead of wasting energy keeping water hot around the clock.
For homeowners already weighing a repair or replacement decision, Cala shows how addressing a water-heater issue can also become an opportunity to lower monthly costs.
Where can I learn more?
• Another homeowner shut off a water heater after a chimney vent warning raised safety concerns.
• For families weighing replacements, tankless water heaters cut costs while delivering hot water on demand.
• Homeowners replacing aging units often find heat pump water heaters offer efficient, lower-cost performance.
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