Humidity_Factor

 So I had Copilot produce a temperature/humidity equivalence chart, for winter indoors.

Below:

                                                                                    

The better explanation on how to read it came from Gemini:

Could you help me read this chart. It is meant to show comfort equivalence for different indoor temperature/humidity combos...

Gemini said

This chart is a great tool for understanding how humidity and temperature work together to create "perceived" comfort. It basically shows that you can feel just as comfortable at a lower temperature if the humidity is higher, and vice versa.

Here is how to navigate it:

1. The Axes (Your Inputs)

Horizontal Axis (X): This is the actual air temperature in degrees Celsius (°C).

Vertical Axis (Y): This is the Relative Humidity (%), ranging from 30% to 50%.

2. The Diagonal Lines (The "Apparent" Temperature)

The colored lines cutting across the chart are isotherms of comfort. Each line represents a specific "feels like" temperature.

Follow a line: If you stay on the line labeled "22," every point on that line feels like 22°C.

The Trade-off: Notice how the lines tilt. For example, if you are at 22°C and 30% humidity, it feels like 22°C. But if you increase the humidity to 50%, you only need the air temperature to be about 21.2°C to feel that same level of warmth.

3. The "Optimal Comfort Zone"

The light gray shaded box in the center represents the "sweet spot" for indoor environments. This zone suggests that most people are happiest when:

The temperature is between 21°C and 24°C.

The relative humidity is between 35% and 50%.

                                                                                                

Why does this happen?

When humidity is higher, moisture evaporates from your skin more slowly. Since evaporation is a cooling process, slowing it down makes you feel warmer. In winter, adding a humidifier can actually help you feel warmer without cranking up the expensive heater!

Would you like me to calculate the "feels like" temperature for a specific reading you have in your home right now?

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Agreed to a rule-of-thumb chart from Copilot:

Here’s a clean, practical table you can use every day.

🌿 Indoor Comfort Rule‑of‑Thumb Table (18–26°C, 30–50% RH)

This table shows how to adjust temperature based on humidity so the room feels equally comfortable.

How to read it

Pick your current humidity.

Look across to find the temperature that will feel similar to your ideal comfort point.

This is based on a simple indoor comfort model:

Higher humidity → feels warmer  

Lower humidity → feels cooler

⭐ Your personalized version

Your preferred winter setting is 23°C, and your humidity tends to sit around 35–40%.

So here’s your tailored table:

This is why:

22°C felt too cool for you this winter

23°C feels “just right”

And why Hydro‑Québec’s algorithm doesn’t understand your lived reality

🧭 What this means for your day‑to‑day comfort

If humidity drops below 35%, your apartment will feel cooler than the thermostat says.

If you keep humidity around 38–42%, you’ll feel warm at 23°C without needing to go higher.

If humidity rises above 45%, you can comfortably lower the thermostat a bit.

This gives you a simple way to balance comfort and energy use without sacrificing warmth.

If you want, I can also create:

A summer version of the table

A dew‑point‑based comfort guide (more accurate than RH)

A one‑page cheat sheet you can print and keep near your thermostat

Just tell me what you’d enjoy next.

Right now, the outdoor temperature is at -2C and the humidity at 74%. (It's about to snow!). What might the humidity in my appartment be. Is there any way to tell?

Good catch on the “it’s about to snow” combo—that’s exactly the kind of moment where outdoor humidity numbers get misleading for indoor comfort.

Here’s the short, honest version.

1. What your indoor humidity probably is right now

With:

Outdoor: about −2°C, 74% RH

Indoor: say 23°C (your current winter setting)

If we track the same air coming inside and just heating it up (no added moisture), the math works out to roughly:

Outdoor dew point: about −6°C

Heated to 23°C indoors → indoor RH ≈ 14–15%

So if your apartment were perfectly sealed and you weren’t adding moisture (cooking, showering, plants, breathing), your indoor humidity would likely be very dry—around 15%.

That’s nose‑bleed, dry‑skin territory.

2. Why that number is only a starting point

Real apartments aren’t just “outdoor air, heated up”:

You add moisture: cooking, boiling water, showers, laundry, even just existing.

Building leaks and ventilation constantly mix indoor and outdoor air.

Materials (wood, fabrics, drywall) absorb and release moisture slowly.

So in practice, your indoor RH might be more like 20–35%, depending on:

How tight your building is

How much you cook/boil water

Whether you use a humidifier

How often you open windows or use exhaust fans

But:

If you don’t run a humidifier and live in a reasonably well‑sealed Québec apartment, it is very plausible that your indoor humidity is under 30% on a day like this.

3. Is there any way to tell without a sensor?

You can only estimate from physics and symptoms:

Likely under 30% if:

Lots of static shocks

Very dry skin, scratchy throat

Lips cracking, nose feels dry

Likely 30–40% if:

Less static

Plants not suffering

You feel “dry” but not painfully so

But to know, you really do need a hygrometer. Even a cheap digital one will tell you if you’re at 18% vs 32%, and that’s the difference between “uncomfortable” and “borderline okay.”

4. Quick rule of thumb for days like today

For cold‑season Québec:

If it’s below 0°C outside and RH is above ~60–70%,

then heated indoor air at 21–23°C will usually be under 25% RH unless you add moisture.

So today’s combo (−2°C, 74% RH, about to snow) almost certainly means:

your indoor air wants to be very dry unless you’re actively humidifying.

If you tell me whether you’re using a humidifier (or not), I can give you a tighter estimate and a simple “if outside is X, expect inside to be around Y” cheat sheet.

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A hygrometer. There are currently 12 in stock at Canadian Tire,  St-Jean-sur Richelieu.