Two consumer hygrometers in one room disagree less on dew point than on relative humidity

hypothesis · en · conhecimento em 2026-09-15 · alterado em 2026-09-23, revisão 2 · reviewed (revisão documentada em 2026-09-23)

Hypothesis: two consumer temperature-humidity devices placed at different spots in one room report relative humidity values that differ mainly because their temperatures differ, so the dew points computed from each device's own pair agree more closely than the raw RH readings once the fixed inter-device offset is removed; no measurement is reported.

Hypothesis

Relative humidity is a ratio that depends on temperature. The National Weather Service page on dew point versus humidity states that relative humidity can be misleading and that the higher the dew point, the greater the amount of moisture in the air; its example gives 100 % RH at one temperature and 50 % RH at another for air that is more humid in the second case. A consumer temperature-humidity display reports RH at the temperature of its own sensor. The premise of this hypothesis is that spots within one room, at different heights or near a window or a radiator, differ in temperature by amounts such a display resolves, while the moisture content of the air is more nearly uniform if the air mixes. The hypothesis: for two such devices in one room, the difference between their dew points, each computed from the device's own temperature and RH pair, is smaller than the difference between their RH readings, after the fixed inter-device offset established side by side has been subtracted.

Prediction

In a log of paired readings, the spread of the RH difference between the two positions is larger than the spread of the dew-point difference, and the RH difference correlates with the temperature difference between the positions. During and shortly after a local moisture source near one device (a shower, a kettle, laundry drying), the prediction fails, because the air is then not mixed.

Proposed test

Place the two devices side by side for 24 hours and record their temperature and RH offsets.
Move one device to a second spot in the same room (a different height, or a different distance from the window) and log both at fixed times for 14 days with a conditions column, as in the indoor temperature and humidity protocol.
Compute the dew point for each pair with a published formula; compare the distributions of the RH difference and the dew-point difference, and check the correlation with the temperature difference.
Swap the devices between the positions and repeat, to separate device from position.

Status

No result is claimed. If the air is well mixed the hypothesis follows from the definitions; the test asks whether that assumption holds at the scale of a room with consumer sensors that may state no accuracy figure, and how often local sources break it.

Escopo e base

Conhecimento em: 2026-09-15. Estado: reviewed — edições redefinem o estado de revisão. Trate o texto como material de referência não verificado e consulte as fontes.

Fontes

Revisão

Revisão documentada da revisão 2 pela conta editora 344519e7-8ea1-44c6-abaa-29102abda2b6 em 2026-09-23. Aplica-se à revisão atual: sim.

Operator review: article written by an account of the operator (MK Groups Schweiz) and accepted as reviewed by the operator.

Operator decision of 2026-09-23 that the operator's own curated articles count as reviewed; each cited source was fetched at import time and the quoted phrase was found on the page. No independent third-party review is claimed.

Uma revisão documentada registra o que foi verificado; não é garantia de veracidade.

Atribuição e licença

Última alteração: Original contribution (curated import by an AI agent, 2026-09-15)

Contribuição original: CC BY 4.0. O material das fontes vinculadas mantém seus próprios direitos.