Thermostats Accuracy

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Last Post by Nayffy 11 months ago

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Nayffy

(@nayffy)

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Joined: 12 months ago

Posts: 4

Topic starter 28/10/2024 12:42 pm

I've got 7 Heatmiser Neostats throughout my house for the UFH but my biggest gripe is the accuracy of the readings (as seen on previous threads on this forum). I have bought several other thermometers to try and calibrate them but all of them give different readings. For example, neostat in the living room shows 21.7C, cheap thermostat from Amazon shows 21.2C, IHD shows 19.5C and Govee thermostat shows 20.4C. I do feel cold in there so I believe it is towards the lower end of all the readings, but I just don't know which one to believe!

Does anyone have any links to an "accurate" thermostat/thermometer that I can trust so I know what temperature it is?

EDIT: I am using W/C so I don't need the readings for turning on and off the heating, just for my own knowledge.

This topic was modified 12 months ago by Nayffy

Grant Aerona3 6kW - UFH 7 Zones controlled by Heatmiser Neostat - S Plan - 3 bed semi built 2020
W/C - 25C @ 17C / 35C @ -3C

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HCas

(@hcas)

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Joined: 2 years ago

Posts: 111

29/10/2024 10:25 am

@nayffy This is definitely something we've observed as well. All temp sensors have errors.
My suggestion would be to pick 1 and increase or decrease your W/C until you're comfortable.

(I know this doesn't answer your question about getting an accurate sensor)

This post was modified 11 months ago by HCas

CEO and co-founder at HavenWise

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Judith

(@judith)

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Posts: 409

29/10/2024 2:50 pm

The best way to handle multiple thermistors/thermocouples! Thermostats indeed any temperature sensor is to do a “cluster test”. Basically you put them all in the same location then allow them to stabilise for a while and then record the values. Calculate the average value of all the readings and select the one nearest to the average as the “true” value. You can buy more accurate temperature indicators but you don’t need one, you simply need to know which one to use as “true”. All sensors have some uncertainty and the indicated value often doesn’t actually matter. Don’t fall in the trap of believing that one which shows more decimal places is more accurate. One meter with one decimal place which is close to true is better than 3 decimal places of apparent (but wrong) accuracy.

2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with it) open system operating on WC

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Nayffy

(@nayffy)

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Joined: 12 months ago

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Topic starter 29/10/2024 3:31 pm

Posted by: @hcas

↑

@nayffy This is definitely something we've observed as well. All temp sensors have errors.
My suggestion would be to pick 1 and increase or decrease your W/C until you're comfortable.

(I know this doesn't answer your question about getting an accurate sensor)

Thanks for the answer, with W/C I'm basically judging on whether I'm comfortable in the clothes I'd normally wear around the house or not. I still have some minor adjustments to make but I'm not really using the thermostats too judge that as 22C in one room can feel freezing compared to 22C in another for some reason!

Posted by: @judith

↑

The best way to handle multiple thermistors/thermocouples! Thermostats indeed any temperature sensor is to do a “cluster test”. Basically you put them all in the same location then allow them to stabilise for a while and then record the values. Calculate the average value of all the readings and select the one nearest to the average as the “true” value. You can buy more accurate temperature indicators but you don’t need one, you simply need to know which one to use as “true”. All sensors have some uncertainty and the indicated value often doesn’t actually matter. Don’t fall in the trap of believing that one which shows more decimal places is more accurate. One meter with one decimal place which is close to true is better than 3 decimal places of apparent (but wrong) accuracy.

A great answer! Unfortunately all the thermostats are hardwired and have no batteries so I'm unable to get them together. I was just hoping there was a reliable thermostat that didn't break the bank that I could use to calibrate the rest of them. I know the neostats are prone to "drifting" and also not very accurate, but I can't afford to replace all 7 of them especially when I don't use them to control the heating, only to satisfy my curiosity of the current temperature.

Grant Aerona3 6kW - UFH 7 Zones controlled by Heatmiser Neostat - S Plan - 3 bed semi built 2020
W/C - 25C @ 17C / 35C @ -3C

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