Temperature discrepancy - how warm is my house?

sand_hun

Hi folks, I've had the Hive heating system for many years. In winter, I generally set the temperature to around 20.5 and it feels OK at this level. I recently bought a digital thermometer (a fairly inexpensive device) from Amazon, but I have noticed that the thermometer seems to suggest my room temps are colder than 20.5. It's a difference of 2 degrees so it displays 18.5. 

Which is likely to be the more reliable reading? Hive or the external thermometer? Thanks  

Beeblebr0x

I've noticed a 1°+ discrepancy between my cheap Amazon thermometer and my hall stat. Although I don't expect the thermometer to be that accurate, I think it gives a more accurate reading than the stat, which seems to exaggerate the actual temperature.

Keep_pedalling

Most of the thermometer you see on Amazon have a claimed accuracy range of +/- 1 degree but I suspect a lot of them have greater variation than that. Two thermometers in the same position showing a difference of 2 degree C would not be unusual if both have an accuracy of plus or minus 1.

ThisIsWeird

Silly Q - did you position the thermometer right beside the Hive? Surfaces and air movement can change readings a fair bit.

FreeBear

Keep_pedalling said:

Most of the thermometer you see on Amazon have a claimed accuracy range of +/- 1 degree but I suspect a lot of them have greater variation than that. Two thermometers in the same position showing a difference of 2 degree C would not be unusual if both have an accuracy of plus or minus 1.

I've found a 2-3°C spread when calibrating a number of digital thermometers & sensors. Some exhibited non-linear errors that required correction curves to be applied. Despite what these Chinese manufacturers claim, reality can be quite a bit different.

Keep_pedalling

FreeBear said:

Keep_pedalling said:

Most of the thermometer you see on Amazon have a claimed accuracy range of +/- 1 degree but I suspect a lot of them have greater variation than that. Two thermometers in the same position showing a difference of 2 degree C would not be unusual if both have an accuracy of plus or minus 1.

I've found a 2-3°C spread when calibrating a number of digital thermometers & sensors. Some exhibited non-linear errors that required correction curves to be applied. Despite what these Chinese manufacturers claim, reality can be quite a bit different.

Yes, I think you need to buy 10 of them and take the average reading. 

Bigphil1474

In our old house, we set our thermostat at 21c in order to get a living room temperature around 19c. In our newer house, we have a portable thermostat and set that at 19.5c to achieve the same. We used a calibrated thermometer I borrowed from work to measure. Having said that, there is a drop of 2.5c between the side we sit on the sofa near the rad to the other side of the living room, which is less than 4 metres away. Personally, I wouldn't worry about which is more accurate, and just decide whether setting the Hive at 20.5c is comfortable.

TELLIT01

The temperature throughout a property will vary.  The only place you can really compare the Hive 'stat temperature to a hand held thermometer is right beside the 'stat.

sand_hun

Thanks for the replies and information. 

@TELLIT01 and @ThisIsWeird the Hive tech has 3 elements. There's a hub next to my WiFi router, there's a device with a display on the wall, and a receiver that is linked to my boiler. Do you think the bit that measures the temp is the actual wall mounted part as that's the thermostat?

Last night I performed a quick test by leaving the Amazon bought thermometer outside. It recorded a temperature of -1.8 compared to the weather App on my phone that recorded -1. Therefore I think the thermometer is fairly accurate.

saajan_12

Different areas of the house will have slightly differing temperatures eg how high off the floor, how close to a heat source and how open that area is. Different thermometers will also perform differently in measuring surface temperature v air temperature, inside v outside with a stronger wind, etc. 

Without several more data points, you can't reasonably determine which is more reliable. 

ThisIsWeird

sand_hun said:

Thanks for the replies and information.

@TELLIT01 and @ThisIsWeird the Hive tech has 3 elements. There's a hub next to my WiFi router, there's a device with a display on the wall, and a receiver that is linked to my boiler. Do you think the bit that measures the temp is the actual wall mounted part as that's the thermostat?

Last night I performed a quick test by leaving the Amazon bought thermometer outside. It recorded a temperature of -1.8 compared to the weather App on my phone that recorded -1. Therefore I think the thermometer is fairly accurate.

I have a Hive too, and - yes - it's the wall-mounted device with the display (the Programmable Thermostat) that has the temp sensing element inside it, and all the stored programming too; it's the bit that 'does stuff'. The receiver just goes 'on' and 'off' when the 'Stat tells it to. The Hub just allows you to communicate with the Prog Stat using the interweb.

I wouldn't use the outdoor temp test as a guide, as the weather App will be quite 'general' to the area; ours suggested temps above freezing all night, but the car screen was still frozen this morn.

But, I have no idea how accurate the Hive actually is. Like BigPhil, I set ours to give us an acceptable temp, and whether that is 'accurate' is largely moot.