When it comes to managing indoor air quality and energy costs during the warmer months, building owners and contractors are always looking for smart, simple solutions. One often overlooked feature built into Cambridge Air Solutions' M-Series is its Summer Ventilation Mode — a small addition with big benefits.
What Is an Economizer?
In HVAC systems, an economizer is a component or control system designed to reduce energy consumption by using outdoor air to cool a building when conditions are favorable.
There are two main types:
1: Dry (Air-Side) Economizer
- Uses cool outside air for “free cooling” instead of mechanically cooled air (compressor-based).
- Operates via dampers that adjust to bring in outside air and exhaust indoor air.
- Common in large commercial systems with ducted return and supply air.
2: Wet (Water-Side) Economizer
- Uses cooling towers or chilled water loops to assist in pre-cooling return air.
- More complex, typically used in data centers or large office buildings.
Economizers rely on sensors and logic controls to determine if outside air is suitable for cooling (based on temperature, humidity, enthalpy, etc.).
How Summer Ventilation Mode Differs
Cambridge Summer Ventilation Mode, while similar in purpose, is much simpler in design and application:
- No dampers, sensors, or logic controls required. It runs purely based on time settings and a manual key switch, without evaluating outside air conditions.
- Unconditioned outside air only. It doesn't mix return air with outside air — it brings in 100% outside air regardless of temperature (with a safety cutoff option).
- Maual or scheduled activation. Can be run on a schedule using the RCS/TSS system, but doesn't dynamically modulate based on external sensors.
- Not designed to replace mechanical cooling, but to complement it by reducing its early-morning burden.
How Summer Ventilation Mode Works 
Using the Remote Control Station (RCS), operators can activate Summer Ventilation Mode via a key switch. Once engaged, the burner is locked out and the unit operates solely as a ventilation fan, pulling in outdoor air and circulating it through the space.
To avoid introducing excessively cold air into the building, the system includes a low-temperature cutout. This safety feature allows operators to set a minimum outside air temperature (in 5-degree increments starting at 40°F). If outdoor temperatures fall below the preset limit, the unit will automatically shut off to protect indoor comfort and prevent freezing.
For added convenience and energy efficiency, Summer Ventilation Mode can also be scheduled through the unit’s Temperature Setback System (TSS). For example, facilities managers can program the unit to run from 5:00 a.m. to 7:00 a.m., allowing the building to flush out warm, stagnant air and replace it with cooler outside air before workers arrive.
Why It Matters: The Value for Contractors and Building Owners
- Reducing Cooling Load
- By bringing in cooler outdoor air during off-peak hours, Summer Ventilation Mode helps "pre-cool" the building naturally. This reduces the indoor temperature heading into the workday, minimizing how hard the mechanical cooling system has to work during the hottest part of the day. While specific energy savings will vary based on conditions, the principle is simple: starting the day cooler helps avoid steep temperature drops that require higher energy consumption.
- Improving Indoor Air Quality
- In addition to temperature benefits, Summer Ventilation Mode continuously introduces fresh air, diluting indoor contaminants, odors, and humidity levels. This is particularly valuable for industrial spaces, manufacturing facilities, and warehouses where air can become stagnant overnight.
- Flexible Operation
- Summer Ventilation Mode also provides operational flexibility. In facilities where processes create heat or exhaust fans run continuously, this mode ensures that a steady stream of outside air replenishes the space, avoiding negative building pressure while maintaining indoor comfort.
- Simple, Built-In Solution
- Unlike complex economizer systems that may require additional equipment and controls, Summer Ventilation Mode is fully integrated into Cambridge's M-Series and S-Series units. There are no additional components to install or configure. This simplicity can benefit contractors during design and installation and serve as a bonus for building owners seeking low-maintenance solutions.
Final Thoughts
Whether you're a contractor designing a ventilation solution or a building owner managing long-term operating costs, Cambridge's Summer Ventilation Mode offers a practical tool to improve comfort and efficiency during the hottest months of the year. It's one more way Cambridge helps facilities achieve better indoor environments without sacrificing simplicity or adding unnecessary complexity.
Next Steps
For Mechanical Contractors: Want to explore how Summer Ventilation Mode can be integrated into your next project? Reach out to your local Cambridge Air Solutions representative to learn more about available configurations, scheduling features, and installation support.
For Building Owners: Curious if your facility could benefit from this feature? Consider scheduling a facility assessment with Cambridge Air Solutions. Our team can evaluate your space and recommend tailored strategies to optimize comfort and energy use year-round.