When you decide it’s time to replace your old, inefficient furnace, the excitement about better comfort and lower energy bills is understandable. Many homeowners mistakenly focus only on the brand, the advertised efficiency rating or the initial price tag. However, the single most important factor determining your long-term satisfaction, your system’s durability and your actual monthly utility savings is proper sizing.

At CJ Hansen, we emphasize that a furnace installation is never a one-size-fits-all solution, especially across the diverse and unique housing styles found in Salem and the greater Willamette Valley. Installing a unit that is either too small or, more commonly, dramatically too large, guarantees years of discomfort, higher energy bills and ultimately, premature system failure.

The Hazards of Improper Sizing

HVAC systems are measured in British Thermal Units (BTUs). Choosing the wrong BTU output for your specific home environment leads to two major, costly problems:

1. Short-Cycling and Component Failure

The common misconception is that “bigger is better.” Homeowners often think an oversized system will heat the house faster. While this is technically true, it creates the problem of short-cycling. Short-Cycling means the furnace generates heat too quickly, satisfying the thermostat’s set point before it has a chance to run a full cycle. It rapidly turns on and off.

Negative Impacts of Short-Cycling:

• • Immense Wear and Tear: The most energy-intensive and stressful part of a furnace’s operation is the start-up sequence. Frequent cycling puts extreme strain on the ignition system, electrical relays and the blower motor, significantly shortening the unit’s lifespan.
  • Humidity Issues and Discomfort: An oversized system does not run long enough to heat the walls and furniture effectively, or, crucially, to dehumidify the air. In the damp Oregon climate, this leads to a “clammy” feeling indoors, even when the air temperature is set correctly.
  • Inefficient Operation: Because the system cycles too often, it consumes excessive energy during the start-up phase, negating the efficiency savings you paid for in a modern, high-AFUE furnace.

2. Continuous Run and Burnout

A furnace that is too small for the heating load of your home cannot keep up with the demands of a cold Willamette Valley winter. Which causes issues like:

• • Constant Running: The unit will run continuously, trying desperately to reach the thermostat’s target temperature. In extreme cold, it may never reach the set point, resulting in high energy bills and frustratingly inconsistent heating.
  • Premature Failure: Running the system non-stop for extended periods accelerates wear and tear, similar to driving your car at maximum RPM for hours on end. This continuous strain leads to early mechanical burnout and a greatly reduced lifespan.
  • Zoned Discomfort: You will experience noticeable temperature variations, with the furnace successfully heating the immediate area around the thermostat but leaving rooms further away, like bedrooms or distant wings, cold.

Determining Your Home’s Needs

How do we determine the perfect size for your new heating furnace? At CJ Hansen we perform a stringent, comprehensive assessment that considers multiple factors unique to your home.
This detailed evaluation ensures the system we recommend has the precise BTUs your specific structure needs.

Key Factors in Determining Size

To find the perfectly matched system, our technicians perform an in-depth analysis of your home’s thermal profile, including:

• • Home Square Footage & Ceiling Height: Larger homes or those with high/vaulted ceilings have a greater volume of air to heat and, therefore, require a furnace with a higher heating capacity to maintain consistent temperatures.
  • Insulation Quality: We assess the insulation quality of your walls, attic and crawlspace/basement. Better insulation means less heat loss, potentially allowing for a smaller, more efficient furnace. Poor insulation requires a larger unit to compensate for heat escaping.
  • Local Climate: We factor in the Willamette Valley’s average low temperatures and seasonal temperature swings. Your heating system must be sized to handle the coldest days on record.
  • Windows and Doors: This is a major source of heat loss. We account for the number, size, orientation (which way they face), type of glass (single-pane, double-pane, low-e) and quality of sealing. A home with many windows may need a larger furnace.
  • Furnace Efficiency (AFUE): A higher Annual Fuel Utilization Efficiency (AFUE) rating means the furnace uses more of its fuel for heating. A more efficient unit may allow for a slightly smaller size to achieve the same heating output.
  • Home Layout and Design: Factors like the number of floors, the overall layout, internal heat loads (from appliances and occupants) and estimated air leakage/infiltration all affect the total heating requirement.

Equipment Selection

Once the ideal size is calculated, we proceed to select the specific model that perfectly matches the required load without exceeding it. This ensures that the unit’s capacity perfectly matches your home’s needs, preventing the short-cycling and continuous run problems associated with incorrect sizing.

Don’t settle for guesswork when making one of the biggest investments in your home comfort.

Ensure Your Investment Pays Off with CJ Hansen

When you’re ready for a new furnace installation, choose precision over guesswork. Contact CJ Hansen today. We’ll size your system right, the first time, ensuring comfortable, efficient heating for years to come.