Can a power outage damage my furnace?

Yes, power outages can damage your furnace, particularly when power is restored. The most common culprit is a voltage surge that occurs when electricity comes back on, which can fry sensitive electronic components.

Modern high-efficiency furnaces are essentially computers with burners attached. They rely on control boards, ignitors, and variable-speed motors that are all vulnerable to electrical surges. Older furnaces with simpler controls are generally more resilient, but no furnace is completely immune. The components most at risk include the circuit board (the most expensive to replace), the inducer motor, and the electronic ignitor.

There are a few other ways outages cause problems. If your furnace was running when power cut out, it may have shut down mid-cycle, which can occasionally cause issues with pressure switches or drainage in high-efficiency models. Repeated outages — common during Ottawa ice storms — are harder on components than a single extended outage.

In the Ottawa area, surge-related furnace repairs typically run $200 - $600 depending on which component is damaged. A control board replacement alone can be $400 - $600 in parts and labour. Given Ottawa's winters, this is a repair you want addressed quickly.

The best protection is a whole-home surge protector installed at your electrical panel, or at minimum a quality surge-protected power bar for your furnace. This is a relatively inexpensive investment — typically $100 - $300 installed — compared to a control board replacement.

After any significant outage, if your furnace won't restart, start with the basics: check that the power switch on the unit is on, check your breaker, and replace the filter if it's been a while. If it still won't fire up, that's the time to call a technician rather than troubleshoot further, as poking around the control board without training can cause additional damage.

If you'd like a technician to inspect your furnace after a recent outage, or to discuss surge protection options, Ottawa HVAC Pro offers service calls throughout Ottawa and the surrounding area.