Assessing Heatmiser Neostat Accuracy: How and Why to Calibrate Them

Heatmiser Neostat

Moving into our home brought the advantage of an already installed underfloor heating system, regulated by Heatmiser Neostats. These devices, promising precise control and energy efficiency, became a focal point of curiosity about their accuracy in temperature regulation after it was raised on a recent YouTube we posted. To assess this, I used a FLIR ONE thermal imaging camera to compare the thermostat readings against the actual environmental temperatures across different heating zones.

The process unveiled unexpected discrepancies between the Neostats’ temperature readings and the thermal camera’s more accurate measurements. Additionally, it highlighted hot spots within the thermostat units, potentially influencing the accuracy of the readings and, by extension, the effectiveness of our home’s heating system.

Motivated by our findings, we recalibrated our Heatmiser Neostat thermostats.

How to Recalibrate Heatmiser Neostat Thermostats

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Derek M
Editor
14051 kWhs
2 months ago

How do you know that the thermal camera or any other reference device is actually providing accurate readings?

What is the manufacturer’s specified accuracy for the devices being compared?

 

Derek M
Editor
14051 kWhs
Reply to  Mars
2 months ago

@Derek M that thought crossed my mind while I was working on this, leading to a humorous vision where I found myself testing the device used for testing the thing that was testing the other thing. 🤣

In the real World, the test equipment should be at least 3 times more accurate than the device being tested. So if the device being tested is specified as providing an accuracy of +/- 1C, then the test equipment should have an accuracy of +/- 0.33C or better.

This works all the way up the chain to National and International standards.

Obviously most people don’t have access to intermediate standards let alone National or International ones, but there are still tests that can be performed at home.

Melting ice will be at 0C and boiling water will be at 100C, under standard atmospheric conditions of 1 atmosphere.

 

AllyFish
3222 kWhs
2 months ago

Heatmiser Neostats are also used by Grant. Theirs are Grant branded, but identical items. They have up to 3degC adjustable differential if I recall, so are well suited to renewable heating system control.

Morgan
4210 kWhs
2 months ago

I had a Heatmiser Neostat installed with my Ecodan.  I was told, I think, by Brendon that it was a simple on-off switch not suited to ASHP control. He advised stripping it out and installing Mitsubishi components.  I did exactly that.

Toodles
5900 kWhs
Reply to  Morgan
2 months ago

@Morgan Likewise, I had a Neo Air Thermostat installed originally, at that time, my choice of a Homely smart controller was not yet available; as soon as the Homely kit was available for my Daikin, I had the system changed over. The Neo Air, is very crude – just on/off and not really very suitable for a heat pump system at all. Regards, Toodles.

Morgan
4210 kWhs
Reply to  Toodles
2 months ago

@Toodles I wish Homely was available for my Ecodan but apparently they have no intention of providing for it.

Toodles
5900 kWhs
Reply to  Morgan
2 months ago
Morgan
4210 kWhs
Reply to  Mars
2 months ago



I had a Heatmiser Neostat installed with my Ecodan.  I was told, I think, by Brendon that it was a simple on-off switch not suited to ASHP control. He advised stripping it out and installing Mitsubishi components.  I did exactly that.

Ours will also probably go when we commence with the work of rectifying our installation. It’s going to be carnage. So much superfluous crap will be removed. 
 

@Mars
You must post a report/summary when it’s done.  I’m keen to know how it goes.  Also still trying to get a Heat Geek to review my install.

Morgan
4210 kWhs
Reply to  Mars
2 months ago


@Morgan we intend to document everything and show the difference. Where in the UK are you based?

@Mars Derbyshire.
 

Morgan
4210 kWhs
Reply to  Mars
2 months ago


@Morgan I’m still looking into this for you – the competent installers that are near you don’t do “repair" work yet – they just want to full installs. I have, however, been given two names of installers that are very reputable – if/when they reply, I’ll put them in touch with you.

@Mars
That’s very kind.  I’ve made contact via two websites here and had no reply so I suspect that they too are only interested in full installs.  Frustrating.
 

Derek M
Editor
14051 kWhs
Reply to  Morgan
2 months ago

@Morgan I’m still looking into this for you – the competent installers that are near you don’t do “repair" work yet – they just want to full installs. I have, however, been given two names of installers that are very reputable – if/when they reply, I’ll put them in touch with you.

@Mars

That’s very kind.  I’ve made contact via two websites here and had no reply so I suspect that they too are only interested in full installs.  Frustrating.

 

I suspect the reason may be that there is no grant that can be applied to repair work, so no opportunity to bump up the price. 🙄 

 

Toodles
5900 kWhs
Reply to  Derek M
2 months ago

@Derek M Oh you cynic you! (And I think you are very close to the truth there!) 😵‍💫 Toodles.

SKD
SKD
730 kWhs
Reply to  Morgan
2 months ago


I had a Heatmiser Neostat installed with my Ecodan.  I was told, I think, by Brendon that it was a simple on-off switch not suited to ASHP control. He advised stripping it out and installing Mitsubishi components.  I did exactly that.
Same for us.  Our Ecodan now runs on WC with all emitters fully open.  Neostats are now used for monitoring only.
 

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