DisplayHDR 400 does not require local dimming at all. Run the VESA certification numbers tier by tier and the real dividing line between 400, 600 and 1000 is not peak brightness — it is the black level.
The '30-pyeong' label on a purifier is not your home's floor area — it is rated coverage derived from CADR. For the same 33㎡ living room, Korea's 130% rule asks for CADR 5.6 while US guidance asks for 10.1.
The right TV size falls between viewing distance ÷ 1.63 and ÷ 1.20. At 2.5 meters that is 60 to 82 inches. A 65-inch 4K panel resolves individual pixels only within 1.3 meters — well inside where most sofas sit.
A dryer's "107 won per cycle" figure assumes a 5kg standard load in eco mode, priced at a rate that excludes the climate levy and taxes. On billed rates the same cycle starts at 126 won.
PSU wattage comes from adding GPU TGP to CPU peak power, then dividing by a target load ratio. Here is the math for an RTX 5090 plus Core Ultra 9 285K — a 905W real load — and what rated wattage should carry it.
The 30dB in ANC marketing is an average below 1kHz. Apply 20dB of attenuation to a 90dB subway car and 70dB remains, feeling about a quarter as loud — here is attenuation converted into perceived loudness, and where passive isolation takes over.
Air conditioners are chosen by cooling capacity in kW, not floor area. The Korean standard is 400W per pyeong, with a 1.3x correction for living rooms.
LDAC's 990kbps is 70% of a CD's data rate; AAC's 256kbps is 18%. But iPhones stop at AAC, and LDAC drops to 330kbps when conditions are poor. Here is every codec converted against the source.
Contrast ratio splits four panel types apart: 1,000:1 for TN, 3,000:1 for VA, effectively infinite for OLED. Converting those numbers into black-level brightness and frame time shows where the spec sheet actually changes the picture.
The industry rule of thumb puts burn-in at around 5,000 cumulative viewing hours. At eight hours a day that arrives in 1.7 years — before Korea's two-year panel warranty expires. Here is the arithmetic against warranties and public longevity tests.