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Passiv Smart Thermostat - Help & Forum Support

Tim441 · 2026-01-12T09:31:57Z

I have a LG Therma V - installed 2020. Controls and data are not great - even if improving in later models. I don't have the ability to setup Home Assistant and so far have not found another good option. I came across Passiv Smart Thermostat which are aimed at many heat pumps I thought I'd add here as potentially of use to others?

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Thermostats, Volumisers, Buffer Tanks, TRVs, Pumps, Piping, Valves, Radiators & Controls

Last Post by Singlespeed 2 weeks ago

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Singlespeed

(@singlespeed)

Trusted Member Member

Joined: 7 months ago

Posts: 51

11/10/2026 12:16 pm

Hi @will-h

After a week or running on the Haier controls, I've just hooked up the Passiv controller and setup the app.

My electric tariff isn't listed in the available options. Would it be possible to add MPAN17 with a smart meter at some point?

I've set the required hot water schedules in the eco heat setup to coincide with the end of the morning and afternoon off-peak times. Which I think should prioritise HW heating in the off-peak rate.

Just selected the single rate tarrif. I guess the only draw back at present will be the calculated bill costs being incorrect... but its the actual electricity bill which matters, so not a big deal on that front.

Thanks, Neil.

👍

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Singlespeed

(@singlespeed)

Trusted Member Member

Joined: 7 months ago

Posts: 51

11/10/2026 7:14 pm

https://www.ovoenergy.com/help/article/electric-heating/economy-10

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Will H

(@will-h)

Active Member Member

Joined: 9 months ago

Posts: 8

14/10/2026 8:58 am

@singlespeed Good to hear it is all installed! We don't have Economy 10 tariffs in the app at the moment, but I have raised it and we will get them added in. 👍

Product Director - Passiv UK

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Singlespeed

(@singlespeed)

Trusted Member Member

Joined: 7 months ago

Posts: 51

14/10/2026 2:29 pm

Posted by: @will-h

↑

@singlespeed Good to hear it is all installed! We don't have Economy 10 tariffs in the app at the moment, but I have raised it and we will get them added in. 👍

Sorry @will-h . Actually I'm now planning to leave OVO in the near future, so I wouldn't bother adding the tarrif unless you want to... theres loads of them if you were to cover all the different metering areas and meters. Then GMT/BST.

👍

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Will H

(@will-h)

Active Member Member

Joined: 9 months ago

Posts: 8

14/10/2026 2:35 pm

@singlespeed No problem. Here is a list of the tariffs we support (which you'll have seen in the app). We see some of the best savings from the tariffs catered for EVs (eg, Octopus Go). https://passivuk.zendesk.com/hc/en-gb/articles/26385141253777-What-time-of-use-tariffs-does-the-Passiv-Smart-Thermostat-support

Product Director - Passiv UK

👍

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EnergyStorageTech

(@energystoragetech)

New Member Member

Joined: 1 month ago

Posts: 6

15/10/2026 7:10 am

The useful test is whether the tariff integration actually changes heating cost without creating comfort swings. I would compare scheduled setpoints, heat-pump response time, hot-water priority and the system’s fallback behavior when the tariff API or internet connection is unavailable.

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JamesPa

(@jamespa)

Illustrious Member Moderator

Joined: 4 years ago

Posts: 5577

15/10/2026 8:01 am

@energystoragetech

The heat capacity of some (many?) houses is pretty large, so there is a lot of smoothing. My house, for example, has a heat capacity of around 15kWh/K as determined by experiment. It has a loss of 7kW at design OAT so, even at design OAT, takes 2 hours to drop 1C if the heating is switched off completely. That offers plenty of scope for playing with set backs/set forwards to do tarrif optimization without compromising comfort.

I really must try it some day (currently I don't bother but it's easy to program a set forward and corresponding set back on my Vaillant)

This post was modified 2 weeks ago 4 times by JamesPa

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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Singlespeed

(@singlespeed)

Trusted Member Member

Joined: 7 months ago

Posts: 51

21/10/2026 4:06 pm

Obviously the weather is changeable but there's a definite drop in electricity usage from the 11th when I connected the Passiv controller.

The outside air temp dropped to -1 overnight on the 16th and 18th but heating the whole house was still only equal to heating the living room prior to installing the heat pump. It looks like I switched on one of the storage heaters on the 25th October last year.

Nov, Dec and January were quite hefty usage last year and I know I'm going to use more electricity at the temperature falls more, but I'm resisting the suggestion by OVO that I need to increase my Direct debit amount from £144 to over £500 per month to break even by April 😂