Snow, Ice, and Rooftop HVAC Units: What Facilities Need to Watch For

Winter in New England brings freezing temperatures, heavy snow, coastal storms, and persistent ice buildup — all of which can take a serious toll on rooftop HVAC units. For many commercial buildings, RTUs are the first line of defense against harsh weather. But without the proper precautions, the same weather they protect you from can cause performance issues, unexpected shutdowns, or even major equipment damage.

Here’s what every facility manager, building owner, and operations team should know to keep critical HVAC equipment running reliably throughout the winter season.

1. Heavy Snow Load and Blocked Airflow

When snow accumulates around an RTU, it restricts airflow to the condenser and evaporator coils. This forces the unit to work harder and can trigger high-pressure shutdowns — or worse, long-term mechanical stress.

What to watch for:

• Snow drifts encroaching on the sides of the unit
• Blocked condenser coils
• Ice crust forming across louvers or intakes

Preventive Measures:
✔ Clear snow from around the unit after major storms
✔ Maintain safe roof access to allow for technician inspections
✔ Consider snow guards or wind deflectors for high-drift areas

2. Ice Buildup on Coils and Components

Ice accumulation can interfere with moving parts, sensors, and drains. On heat pumps or units operating in heating mode, coil icing is especially common.

Risks include:

• Frozen fan blades
• Blocked drains leading to water leaks inside the building
• Prolonged defrost cycles reducing heating capacity
• Coil damage from expanding ice

Prevention Tips:
✔ Ensure defrost cycles are programmed correctly
✔ Keep drain lines clear and heated if necessary
✔ Schedule mid-season inspections to catch issues early

3. Freezing Temperatures Affecting Controls and Sensors

Extremely cold weather can cause sensors to fail or send inaccurate readings — leading to erratic system operation or premature shutdowns.

Look out for:

• Faulty discharge air sensors
• Outdoor air temperature sensors reading incorrectly
• Frozen economizer components

Solutions:
✔ Calibrate sensors regularly
✔ Use cold-weather-rated components where possible
✔ Install low ambient controls designed for New England climates

4. Roof Conditions That Create Hidden Risks

Your rooftop itself can become part of the problem if winter weather isn’t addressed proactively.

Watch for:

• Ice dams around equipment
• Excessive roof flex under heavy snow load
• Water ponding during thaw cycles
• Unsafe access paths for technicians

Mitigation:
✔ Incorporate rooftop clearing into your winter maintenance plan
✔ Maintain designated access paths for service
✔ Ensure RTUs are installed on curbs high enough to avoid drifting snow

5. Loss of Heat = Frozen Pipes Inside the Building

A rooftop HVAC failure can quickly lead to interior temperature drops — and frozen pipes can occur faster than many realize.

Preventive Strategies:
✔ Set up monitoring for low indoor temperatures
✔ Ensure emergency heat sources are functional
✔ Have a 24/7 service partner (like Northstar) ready for immediate response

How Northstar Refrigeration Helps Protect Your Facility All Winter Long

Harsh winter weather is unavoidable, but equipment problems don’t have to be.

Northstar provides:

• Winter HVAC inspections and seasonal prep
• 24/7 emergency service for critical systems
• Preventive maintenance designed for New England conditions
• Rapid-response spare parts support to minimize downtime
• Proactive monitoring and system performance evaluations

📞 Need help preparing your rooftop HVAC units for winter storms?
Call (508) 888-3692 — Our team is ready day and night.

‍