Unexpected Load Values

These results often look like errors but are usually correct behavior driven by inputs, orientation, thermal mass, or the selected standard.

Heating loads are higher than cooling loads in a warm climate

This is typically caused by modeling inputs, not actual building behavior. Common causes:

• Missing internal and ventilation loads. If internal gains (people, lighting, equipment) and ventilation aren’t included, cooling loads appear artificially low.
• Reduced summer dry-bulb temperature. Lowering the design dry bulb (for example, for a dehumidification scenario) cuts external cooling load and can make heating look larger by comparison.
• Latent load not captured. Designing for a higher wet bulb increases latent load — but if ventilation/infiltration is excluded, that latent load never shows up in results.

Cooling loads depend heavily on internal gains, ventilation/infiltration, and accurate weather inputs. If those are reduced or excluded, cooling can drop below heating even in warm climates. Review Cooling Loads and confirm internal and ventilation loads are included.

Peak cooling occurs late in the day

Late cooling peaks come from a combination of orientation, wall thermal mass, and the mix of load components:

• Orientation. Spaces with mostly north and northwest exposure receive less direct solar gain early in the day, shifting the peak into the afternoon.
• High-mass walls. High-mass assemblies delay heat transfer — conductive load can take 4–5 hours to pass through the wall, pushing the peak later than the outdoor temperature peak.
• Excluded load components. If ventilation or scheduled internal loads are excluded, there’s less early-day load to pull the peak forward.

To shift the peak earlier, you can choose a lighter wall assembly in Wall Data. Even then, a late peak may be expected depending on orientation and the overall load mix. This is the RTS method working as intended — see Cooling Loads.

Outdoor air is higher than the People + Area equation

HVAKR applies the ASHRAE 62.1-2025 altitude correction factor by default. At elevation, air density is lower, so the required outdoor air volume increases.

Example at ~3,500 ft:

• Base: (People × CFM/person) + (Area × CFM/ft²) = 471 CFM
• Altitude correction factor: ~1.15
• Final OA: 471 × 1.15 ≈ 542 CFM

Notes:

• The altitude correction is part of the 2025 ventilation standard. Low-elevation projects show little or no difference.
• To remove it, go to Project Settings and change the ventilation standard from 2025 to an earlier version. The OA value returns to the uncorrected figure.

See Ventilation and ASHRAE 62.1.