Low-Voltage Ventilation Retrofit: Why Electrical Demand Matters

At first glance, the electrical cost of operating a pair of LUNOS units appears insignificant — and it is. A typical pair consumes only a small number of kilowatt-hours per year. But that modest fan energy is not the point. What matters is what low electrical demand makes possible. When ventilation is inexpensive to operate, it can run continuously. Continuous, predictable ventilation reduces occupant-driven behaviours such as window opening and pressure manipulation. Reduced behavioural variability lowers the compensatory burden placed on centralized air handling systems. Over time, that stabilization — not the fan wattage itself — is where meaningful energy performance gains emerge.

Over 50% of residential buildings in Canada are more than 30 years old, and more than 20% are over 50 years old. As this aging building stock undergoes retrofit, the primary energy challenge is not lighting or controls — most of that low-hanging fruit has already been addressed. The dominant energy driver in cold climates is the movement, heating, and cooling of air.

Ventilation is therefore central to energy performance. Yet in many older buildings, ventilation remains inconsistent, behaviour-driven, or overly dependent on centralized systems designed under different assumptions. When occupants open windows, disable fans, or rely on intermittent exhaust, centralized systems must compensate. The result is higher heating demand, greater mechanical stress, and unstable energy performance.

The question is not simply how to add ventilation — it is how to stabilize it. Low-voltage LUNOS ventilation enables continuous, heat-recovery air exchange at the suite level without introducing meaningful electrical burden. This shifts ventilation from a reactive, behaviour-dependent function to a predictable building service — reducing reliance on centralized air handling systems and supporting broader energy retrofit objectives.

In cold climates, the largest energy penalty in older buildings is often not the fan energy itself, but the heating and cooling of air that moves unpredictably through the building. When ventilation is intermittent or behaviour-driven, centralized systems must compensate for uncontrolled air exchange, increasing runtime, heating demand, and mechanical stress. Stabilizing air exchange at the suite level reduces this compensation effect. Low-voltage LUNOS ventilation enables that stabilization without introducing new electrical strain.

In retrofit projects, ventilation performance cannot be separated from energy use and electrical demand. Unlike many building systems that are designed around peak or intermittent demand, ventilation is a continuous service requirement — making low-voltage ventilation retrofit strategies particularly well suited to existing buildings. Regardless of system type, it represents an ongoing electrical load that directly affects operating cost, system feasibility, and long-term reliability.

The principles below outline the conditions that make stability, energy demand, and electrical feasibility central to ventilation decisions in retrofit buildings:

Each of these principles reflects a constraint routinely encountered in retrofit projects. The discussion that follows expands on how these conditions manifest in practice and why low-voltage LUNOS ventilation is uniquely suited to operate within them.

In existing buildings undergoing retrofit, ventilation is rarely added to a blank slate. Existing buildings—whether single-family homes or multi-unit residential buildings—come with inherited electrical systems, mechanical constraints, and long-standing occupant habits. As these buildings are upgraded, ventilation must be improved without creating new electrical burdens, operational complexity, or ongoing energy penalties.

In many older buildings, ventilation has historically been intermittent and reactive rather than continuous. Fresh air has often been provided through whatever means were readily available rather than through a deliberate ventilation strategy. This approach introduces variability in indoor air quality and energy performance and places unnecessary reliance on occupant behaviour to compensate for system limitations, particularly in cold climates.

That variability does not remain isolated at the suite level. When airflow is inconsistent, centralized heating and air-handling systems must respond to compensate for pressure imbalance, uncontrolled infiltration, and fluctuating load conditions. The result is increased energy demand across the building as a whole — not simply higher fan wattage, but greater heating and cooling burden driven by unstable air movement.

This is where electrical and energy demand become defining characteristics of ventilation strategy. Because ventilation operates continuously, its influence on centralized system runtime and heating demand accumulates over time. Stabilizing airflow reduces compensation at the system level — but any solution must do so without introducing new electrical strain.

That requirement for continuous stabilization must also respect the electrical reality of older buildings. Electrical systems were designed for different operating assumptions, and adding new continuous loads can quickly expose their limits. In retrofit projects, even modest additional electrical demand can trigger costly upgrades or force difficult trade-offs between systems.

LUNOS addresses these constraints by delivering continuous heat-recovery ventilation with exceptionally low electrical input. Because each unit draws only a few watts, suite-level stabilization of airflow can be achieved without meaningfully increasing building-wide electrical burden. This allows ventilation to operate predictably and continuously, reducing reliance on centralized systems to compensate for inconsistent air exchange.

Continuous stabilization only works if it is electrically practical. The table below quantifies the annual electrical load associated with a typical paired LUNOS configuration operating continuously across Canadian provinces.

Assumptions: Continuous operation (8,760 hours/year). Average electrical input of 2.5 W per unit (5.0 W per pair). These estimates are based on continuous operation, typical paired LUNOS configurations, and representative provincial electricity rates. Actual operating costs will vary based on usage patterns and local utility pricing, but the values shown illustrate the consistently low electrical demand associated with LUNOS ventilation.

In individual homes, the systemic effects described above operate at smaller scale — but they remain structurally the same. Ventilation is still a continuous service requirement, and instability still carries energy consequences.

In older homes, ventilation has often depended on intermittent exhaust fans, window opening, or occupant intervention. These approaches introduce variability in airflow and heating demand, particularly in cold climates. When ventilation fluctuates, heating systems must respond dynamically, increasing cycling and reducing overall energy stability.

By operating continuously at very low electrical input, LUNOS stabilizes suite-level airflow without introducing a meaningful electrical burden. This makes continuous ventilation viable in homes where panel capacity, wiring access, or upgrade budgets are limited. For homeowners undertaking phased renovations, LUNOS can be integrated incrementally — room by room — without requiring major electrical reconfiguration. The ventilation strategy can evolve with the retrofit rather than waiting for a full mechanical overhaul.

In solar-assisted, battery-based, or off-grid homes, the effect is amplified. Continuous loads directly affect inverter sizing and storage capacity. Because LUNOS operates at exceptionally low and predictable power levels, it allows stable, continuous ventilation without compromising energy autonomy.

In individual homes, the importance of continuous ventilation extends beyond the electricity required to operate the units themselves. It is about making continuous ventilation structurally feasible — stabilizing airflow, supporting heating system performance, and fitting realistically within the electrical and retrofit constraints of the home.

In multi-unit residential buildings, the importance of low-voltage ventilation is amplified by scale. Just as in individual homes, ventilation is a continuous service requirement. In MURBs, however, that continuous load is multiplied across dozens or hundreds of suites. Even modest per-suite demand becomes material at the building level, influencing mechanical system sizing, operating cost, and retrofit feasibility. In large buildings, the interaction between suite-level airflow, centralized systems, and thermal conditioning becomes a structural component of overall building performance rather than a minor operational detail.

Historically, MURBs have relied on centralized mechanical systems to manage ventilation variability. Corridor pressurization, make-up air units, and large exhaust systems are often expected to compensate for inconsistent in-suite ventilation and occupant behaviour. In practice, this means windows are opened for fresh air during heating season, exhaust fans are used intermittently or relied upon to induce negative pressure, and ventilation delivery becomes inconsistent rather than continuous. These behaviours introduce uncontrolled air movement. Centralized systems respond by increasing runtime, altering pressure relationships, and conditioning additional outdoor air to maintain balance. Over time, this compensation model increases fan energy, heating demand, and mechanical strain. The primary cost driver is not the electricity required to move air, but the energy required to heat or cool air that enters the building unpredictably.

LUNOS changes this dynamic by redistributing a portion of continuous ventilation demand directly into the suites without imposing a building-wide electrical penalty. Because each LUNOS unit operates at exceptionally low power, distributing ventilation across many suites does not create the cumulative impact typically associated with suite-level systems. Instead of concentrating airflow responsibility in centralized equipment, ventilation becomes locally stable and continuous. Continuous suite-level ventilation reduces reliance on behavioural workarounds. Windows remain closed during extreme weather, and exhaust fans return to their intended function — localized moisture control — rather than being used to induce pressure differences for fresh air. As a result, pressure fluctuations are minimized, airflow paths become more predictable, and centralized systems are no longer forced to compensate for uncontrolled air exchange. This stabilizes airflow patterns throughout the building and reduces the compensatory runtime required of centralized air handling equipment. When uncontrolled air exchange is reduced, centralized systems no longer need to increase fan speed, outdoor air intake, or heating output to maintain pressure balance and thermal stability. The result is not simply lower centralized fan energy, but reduced variability in conditioned air movement — a critical distinction in cold climates where every unit of uncontrolled outdoor air carries a heating penalty.

In retrofit scenarios, feasibility ultimately determines whether ventilation improvements occur at all. Older MURBs often operate with constrained electrical infrastructure, where adding new continuous loads can trigger costly service upgrades or distribution changes. At the same time, invasive ductwork or wholesale mechanical redistribution are typically impractical in occupied buildings. LUNOS aligns with both constraints. Its small, predictable per-suite electrical demand avoids compounding service capacity, while its through-wall, suite-level configuration eliminates the need for centralized duct expansion or major interior demolition. Once a single suite installation approach is established, deployment becomes repeatable and scalable across the building. This combination — limited electrical impact and non-invasive, replicable installation — allows ventilation improvements to be implemented incrementally or integrated into broader retrofit programs without escalating scope or disruption.

These principles have been applied in practice through multi-unit retrofit projects, including deep energy retrofits where LUNOS was integrated alongside broader building improvements. While the sequencing and scope of work vary across projects, the underlying logic remains consistent: stabilize suite-level ventilation, reduce centralized compensation, and improve energy performance without compounding electrical demand or destabilizing existing systems.

In this context, LUNOS functions as a structural component of the broader energy strategy — supporting reduced mechanical compensation, improved airflow stability, and retrofit feasibility at scale.

Questions about applying these principles to a specific project?

LUNOS Canada can provide technical guidance on integrating low-voltage, suite-level ventilation into retrofit strategies for individual homes and multi-unit residential buildings.

The principles discussed in this article have been applied in practice through deep energy retrofit projects where LUNOS was integrated to provide continuous, low-voltage ventilation within broader retrofit programs. The related project articles linked at the end of this article show how LUNOS has been implemented in real multi-unit retrofit projects.