The short version
- TempPro states humidity accuracy of ±2% between 30 and 80 percent relative humidity (±3% outside that band) and temperature accuracy of ±1°F. It refreshes every 10 seconds.
- $10.99 on Sep 30, 2026, sold by TempPro HOME and fulfilled by Amazon. It runs on one AAA battery, which is included; there are no other running costs.
- Its smiley "Comfort" icon covers 30–60 percent humidity. The EPA's ideal indoor range is 30–50 percent, so read the number, not just the face.
Cooking steam skews the reading, and it is not a food thermometer.
Useful next to a humidifier. There is no backlight, so it will not glow at night.
Shower steam pins it at the top of its range; place it outside the bathroom.
A central shelf or wall gives the best read on the whole floor.
Solid yellow = where it lives · hatched = also works there
What the spec sheet shows
We read the Amazon listing, TempPro's TP50 product page and the TP50 user manual PDF on Sep 30, 2026. The listing's brand and store are TempPro, and the model field reads "TempAir CORE TP-50". TempPro's page notes that orders may arrive in packaging with the company's previous brand name. The Amazon listing's own web address still carries the ThermoPro name, and TempPro's site keeps ThermoPro-branded pages for sibling models.
| Spec | Value | What to know |
|---|---|---|
| Humidity range | 10 to 99 percent RH | Relative humidity, shown in 1% steps. |
| Humidity accuracy | ±2% (30–80% RH); ±3% otherwise | A reading of 50% means roughly 48–52%. |
| Temperature range | −58 to 158°F | Shown in 0.1° steps; °F or °C. |
| Temperature accuracy | ±1°F (±0.5°C) | TempPro's stated tolerance. |
| Refresh rate | 10 seconds | Give it time to settle after you move it. |
| Records | High / low | Humidity and temperature since the last reset. |
| Comfort icon | Dry / Comfort / Wet | Dry below 30%; Comfort at 30–60% and 68–79°F; Wet above 60%; no icon otherwise (manual). |
| Sensor | NTC | As TempPro lists it. |
| Display | LCD, no backlight | Per the spec table. One product title on TempPro's site says "backlit"; the spec table and our photo show a plain LCD. |
| Size and power | 3⅛ × 2⅝ × 1 in; 1 × AAA | Tabletop stand and magnetic back. |
What the standards and sources say
The target range. There is no certification for a home hygrometer. The useful reference is the EPA's guidance on indoor moisture. Its mold and moisture guide says to keep indoor relative humidity below 60 percent, ideally between 30 and 50 percent [3]. It adds that a humidity meter is a small, inexpensive instrument ($10–$50) sold at many hardware stores. The EPA's humidifier page says not to humidify above 50 percent, and it names a hygrometer as the way to measure [4]. The CPSC gives the same 30–50 percent range and suggests a hygrometer for checking it [5]. Our indoor humidity explainer goes through what relative humidity is and how it moves with temperature.
The comfort face versus the EPA range. According to the manual, the TP50 shows its "Comfort" smiley when humidity is 30–60 percent and the room is 68–79°F [2]. That band reaches 10 points past the EPA's 50 percent ideal. The display can smile at 58 percent while the EPA would call that high. If you are steering a humidifier with it, go by the number.
How much to trust the digits. A ±2% tolerance is fine for deciding whether a room sits near 35 or 55 percent. It is not precise enough to argue about 49 versus 51. TempPro's FAQ describes a salt check [2]: a damp slush of table salt sealed in a bag with the unit for about 6 hours should read 75 percent. The FAQ says the TP50 can be adjusted to match. The two-page manual we opened does not describe an adjustment procedure, so we could not confirm how that is done. At minimum, the test tells you how far off your unit reads, and you can correct for that in your head.
The listing also calls it a "wellness indicator" and makes health-benefit claims about humidity. We do not repeat those. It is a meter; it measures and does nothing to the air.
Placement decides whether the number means anything. Next to a humidifier's mist, above a radiator, in a sunny window or by a bathroom door, it will report that spot, not the room. It has no alarm, no app and no backlight. TempPro sells connected and backlit models if you need to check readings from another room or in the dark.
How to set it up and keep it up
This combines the TP50 manual with a few placement habits of our own, marked as such. It is how to get a sensible reading, not a promise about your home.
Insert the battery and pick units day one
Put the included AAA battery in with the polarity shown. Press the °F/°C button once to switch units.
Place it and let it settle day one
Our suggestion: stand it or stick it (magnetic back) at about chest height on an inside wall or shelf. Keep it away from vents, direct sun, the humidifier's mist and the bathroom door. Give it 15–30 minutes before trusting the first reading.
Read it and clear the records weekly
Check the high and low values to see how the room swings at night or when the heat runs. Hold the °F/°C button for 2 seconds to clear them and start a fresh window.
Run the salt check once a year
Following TempPro's FAQ: a tablespoon of table salt, a few drops of water, sealed in a zip bag with the unit for about 6 hours. It should read close to 75 percent; note any offset.
Store it right if unused 4+ months
The manual says to take the battery out if you store it for more than four months, not to immerse it, and to keep it away from extreme heat and cold.
Price and where it is sold
On Sep 30, 2026 the listing showed $10.99 for one TP50, sold by TempPro HOME and fulfilled by Amazon, with a free 30-day refund or replacement. TempPro's own store listed a single unit at $15.99 that day. TempPro's FAQ gives a 1-year warranty, extendable to 3 years after registration. The only running cost is an AAA battery. Prices move; these are the figures from that date.
Who should look elsewhere
- Anyone who wants to see readings on a phone or get an alert. This is a stand-alone display.
- Anyone who needs readings in the dark or across the room. There is no backlight, and the digits are sized for a shelf, not a hallway.
- Anyone who needs precision for storing instruments or collections. A ±2–3% consumer meter is a guide, not a reference instrument.
- Anyone with a health question about indoor humidity or damp should ask a clinician or their local health department.
Sources
- Amazon.com. TempPro TP50 Digital Hygrometer Indoor Thermometer listing, ASIN B01H1R0K68 (model TempAir CORE TP-50): price, seller, returns, details. Viewed Sep 30, 2026.
- TempPro. TempAir CORE TP50 product page (specifications, FAQ, brand note, price). Accessed Sep 30, 2026. link · TP-50 user manual, PDF. link
- U.S. Environmental Protection Agency. A Brief Guide to Mold, Moisture and Your Home. Accessed Sep 30, 2026. link
- U.S. Environmental Protection Agency. Use and Care of Home Humidifiers. Accessed Sep 30, 2026. link
- U.S. Consumer Product Safety Commission. Safety alert on dirty room humidifiers, Publication 5046, PDF. Accessed Sep 30, 2026. link
This entry is general information about a household product, not medical advice. Household air, water and kitchen products are not medical devices. Follow the manufacturer's manual for installation, use and maintenance.