NPIPE applies a low-pass filter to the LFI load signal before decorrelation. In PR3, a single scaling coefficient was fitted each operational day. We demonstrate the two approaches for one pointing period on two diodes: LFI2500 (left), with a relatively low amount of 1/f noise; and LFI1800 (right), which is dominated by 1/f at all frequencies. Top: power spectral densities of sky and best-fit load signals. Bottom: power spectral densities of sky−load differenced signals. The PSDs were binned into 300 logarithmically-spaced bins for clarity. The scaled load template leaves more noise at both high and low frequencies than a filtered version, where the uncorrelated power is suppressed. When the 1/f fluctuations dominate across the spectral domain, the scaling and filtering approaches achieve effectively the same result.