Question Why do my thermometers differ in readings ?

[Airlane1979]

I have two room thermometers inside digital clock devices. They consistently differ by 1.3 degrees Celsius when placed adjacently. Why is this? It's a substantial difference. Should I obtain a mercury thermometer for a more accurate measure?

 

[bill001g]

If the difference stays the same it is likely they were not set correctly at the factory. They technically can be set to display any number for any temperature. All depends on if there is any method to adjust this.

The thermometers I use in the kitchen want you to calibrate them using ice water to set zero.

Mercury is not going to be any more accurate...assuming you can even get thermometers with mercury. It all depends on how accurately they marked the tubes at the factory.

Even on amazon they sell thermometers that are designed to be extremely accurate. All depends on how accurate you want it to be.

 

[Airlane1979]

If the difference stays the same it is likely they were not set correctly at the factory. They technically can be set to display any number for any temperature. All depends on if there is any method to adjust this.

The thermometers I use in the kitchen want you to calibrate them using ice water to set zero.

Mercury is not going to be any more accurate...assuming you can even get thermometers with mercury. It all depends on how accurately they marked the tubes at the factory.

Even on amazon they sell thermometers that are designed to be extremely accurate. All depends on how accurate you want it to be.

Interesting! Neither device has a means to calibrate it. So I'm not sure what the true temperature is.

 

[SkyNetRising]

Interesting! Neither device has a means to calibrate it. So I'm not sure what the true temperature is.

Why does that matter?
Every measurement will have some amount of error.

You can get several more digital thermometers and then average their readings.

 

[Airlane1979]

Why does that matter?
Every measurement will have some amount of error.

You can get several more digital thermometers and then average their readings.

That's not really a practical method to know the temperature of the rooms in my home. Should each room have, say, five thermometers?

 

[SkyNetRising]

That's not really a practical method to know the temperature of the rooms in my home. Should each room have, say, five thermometers?

Again. Why does that matter?
Why do you need temperature readings to be precise?

So you have one reading 22C and the other 23C.
Then probably real reading is somewhere in between.

 

[bill001g]

just buy a very precise thermometer and compare all your current ones. You can put a small sticker showing the offset and you can just calculate the difference every time you look at the thermometer.

 

[Airlane1979]

just buy a very precise thermometer and compare all your current ones. You can put a small sticker showing the offset and you can just calculate the difference every time you look at the thermometer.

How do I know which is the precise one?

 

[Phillip Corcoran]

The most accurate room thermometers in my experience are the traditional "linear" type which have a glass tube with liquid inside, mounted on a piece of wood or plastic.

 

[Airlane1979]

The most accurate room thermometers in my experience are the traditional "linear" type which have a glass tube with liquid inside, mounted on a piece of wood or plastic.

That's what I thought. No-one here has yet suggested any other solution.

 

[Airlane1979]

Again. Why does that matter?
Why do you need temperature readings to be precise?

So you have one reading 22C and the other 23C.
Then probably real reading is somewhere in between.

How do I know that the true temperature is between? It might lie above or below.

 

[SkyNetRising]

How do I know which is the precise one?

There are high precision thermometers.
You probably wouldn't want to spend $3000 for one.

That's why I asked - why does it matter for you?
If you have some technological process, that requires ultra precise temperature measurements,
then invest in a high precision thermometer.
But if it's just for temperature readings in your room, then who cares.

https://www.instrumart.com/categories/791/precision-thermometers

 

[Airlane1979]

There are high precision thermometers.
You probably wouldn't want to spend $3000 for one.

That's why I asked - why does it matter for you?
If you have some technological process, that requires ultra precise temperature measurements,
then invest in a high precision thermometer.
But if it's just for temperature readings in your room, then who cares.

https://www.instrumart.com/categories/791/precision-thermometers

Which is interesting but no solution. My two digital devices are 1.3C apart. I'd like a room thermometer that's accurate to 0.5C. Is that too precise to ask for? I suspect a mercury device will provide that.

 

[SkyNetRising]

I'd like a room thermometer that's accurate to 0.5C. Is that too precise to ask for?

Every reading will have some level of error. You can't really avoid that.

Precision will cost you.
Either for multiple cheap thermometers. And then you can calculate average and deviations.
Or for expensive high precision device.

 

[USAFRet]

Which is interesting but no solution. My two digital devices are 1.3C apart. I'd like a room thermometer that's accurate to 0.5C. Is that too precise to ask for? I suspect a mercury device will provide that.

Take one or both of yours to a local college.
Speak to someone in the science dept.

Possibly they have a way to compare it to a known good one.

 

[bill001g]

How do I know which is the precise one?

It depends on how accurate you actually want. Look on amazon they have a bunch that look like multimeters and cost under $30. My multimeter actually has a temp probe.

Most of these say they have accuracy of .1C in the range you are asking for. They are less accurate when you get very hot or cold. Many can measure well over 1000C