Should I install an HRV in my insulated garage to manage humidity in NB winters?

Yes — if you're heating and insulating your garage in New Brunswick, an HRV is one of the smartest investments you can make, though it's not the only option and the right choice depends on how you use the space.

An insulated, heated garage in NB creates a sealed thermal envelope that traps moisture aggressively. Every time you pull a snow-covered vehicle in from a -20°C night, that vehicle releases a significant amount of water vapour as it warms up. Add road salt tracking in on tires, wet boots, breath from people working in the space, and any propane or natural gas combustion from a unit heater, and you have a serious moisture load building up inside a tight building. Without mechanical ventilation, that moisture has nowhere to go — it condenses on cold surfaces, soaks into drywall, promotes mould behind insulation, and accelerates rust on tools and vehicles.

HRV vs. Simpler Exhaust Ventilation

A Heat Recovery Ventilator (HRV) exchanges stale, humid indoor air with fresh outdoor air while recovering 70–80% of the heat from the outgoing air stream. In a garage you're heating to 15–18°C while it's -25°C outside, that heat recovery matters — without it, every cubic foot of air you exhaust is replaced by outdoor air your heater has to warm from scratch. An HRV sized for a typical two-car garage (24x24, roughly 400 sq ft with 9-foot ceilings) would be a small residential unit in the 60–100 CFM range, costing $800–$1,800 for the unit plus $500–$1,200 for installation, depending on ductwork complexity. That's a $1,300–$3,000 investment.

The honest alternative worth considering first is a through-wall exhaust fan with a motorized damper — a 6-inch or 8-inch unit with a timer or humidistat control. These cost $150–$400 installed and do a reasonable job of purging moisture after a vehicle enters. The tradeoff is that you're exhausting heat you've paid to generate, with no recovery. In a garage you heat continuously through a six-month NB winter, that heat loss adds up. If your garage heater is running on natural gas or propane and you're maintaining temperature daily, the energy savings from an HRV can meaningfully offset its cost over 5–10 years.

When an HRV Makes the Most Sense

The case for an HRV strengthens considerably if your garage doubles as a workshop, home gym, or hobby space where people spend extended time — not just the 10 minutes it takes to park a car. Occupied spaces benefit from continuous fresh air exchange in ways that a simple exhaust fan on a timer doesn't fully address. If you're running an attached garage that shares HVAC with the house, your home's existing HRV may already be handling some of this load, though garage air (with vehicle exhaust potential) should ideally be kept on a separate ventilation circuit for safety reasons.

A humidistat-controlled exhaust fan is a practical middle ground for garages used primarily for vehicle storage with occasional weekend workshop use. Set the humidistat to trigger the fan at 50–55% relative humidity, and it runs only when moisture levels actually warrant it. This costs a fraction of an HRV and handles the moisture load without continuous heat loss.

Practical Installation Notes

Regardless of which system you choose, the exhaust point should be located low on the wall near the garage door — that's where cold, damp air from incoming vehicles pools. Fresh air intake, if your system has one, should be on the opposite wall up high. Make sure any wall penetrations are properly sealed with foam backer rod and caulk on the exterior to prevent air infiltration around the sleeve. In NB's climate, unsealed penetrations become frost bridges and moisture entry points within a season or two.

A carbon monoxide detector is non-negotiable in any heated garage, HRV or not. Ventilation helps dilute CO from cold starts, but it is not a substitute for a detector.

If you're at the planning stage and haven't poured your slab yet, this is also the right time to think about in-slab vapour barrier (6-mil poly minimum) and perimeter drainage — both reduce the ground-source moisture load that ventilation alone can't address.

For help finding a licensed electrician or HVAC contractor to assess your garage ventilation options, browse the New Brunswick Construction Network directory at newbrunswickconstructionnetwork.com.