Cheap way to smart TRVs? Anyone using SwitchBot TRVs?
Discussion
I've been looking at Honeywell EvoHome type systems for a while, and despite being well regarded they're not cheap for what they are.
Switchbot seem pretty good and well regarded. I have a bunch of their sensors already and they've all been good, the software is seemingly good, can all run locally (no cloud), and the bluetooth connections seems solid.
These are cheap right now.
https://www.amazon.co.uk/SwitchBot-Thermostat-Ener...
For 17 of these for all my rads it's about 1/3rd the cost of biggest/best value EvoHome kit with extra TRVs.
So all great, but I need a way to switch the boiler on and off. Their website seems pretty crap in that regard, and their help AI didn't even understand my question.
I can't imagine that SwitchBot are so daft that they overlooked this issue, and seem to infer that you have some connected device (Matter connected, or Apple Home?, I've never used these and no idea how they actually work either) get triggered by these TRVs, and then that deals with the boiler, but they don't offer any real flow-chart type info on how that works and I'll admit I'm a bit lost, and would prefer to not include Apple Home or other type stuff into the mix because it really doesn't feel like it needs to be that complex.
I just want TRVs to call for heat, and the boiler to turn on.
SwitchBot also do these:
https://www.amazon.co.uk/s?k=switchbot+relay
Which are cheap and look like a simple switched relay. I assume then that my combi boiler can just have the CH switch run off one of these, and then the SwitchBot TRVs can all just talk to the hub, and when one or more want heat they can just turn the CH on at the boiler?
I'm not an expert on it all but this seems a pretty elegant setup assuming you don't want a wall panel with controls and be tweaking things regularly... I do like the idea of that with the EvoHome, but not for £1,000 extra cost and what is by now a decade+ old system.
Switchbot seem pretty good and well regarded. I have a bunch of their sensors already and they've all been good, the software is seemingly good, can all run locally (no cloud), and the bluetooth connections seems solid.
These are cheap right now.
https://www.amazon.co.uk/SwitchBot-Thermostat-Ener...
For 17 of these for all my rads it's about 1/3rd the cost of biggest/best value EvoHome kit with extra TRVs.
So all great, but I need a way to switch the boiler on and off. Their website seems pretty crap in that regard, and their help AI didn't even understand my question.
I can't imagine that SwitchBot are so daft that they overlooked this issue, and seem to infer that you have some connected device (Matter connected, or Apple Home?, I've never used these and no idea how they actually work either) get triggered by these TRVs, and then that deals with the boiler, but they don't offer any real flow-chart type info on how that works and I'll admit I'm a bit lost, and would prefer to not include Apple Home or other type stuff into the mix because it really doesn't feel like it needs to be that complex.
I just want TRVs to call for heat, and the boiler to turn on.
SwitchBot also do these:
https://www.amazon.co.uk/s?k=switchbot+relay
Which are cheap and look like a simple switched relay. I assume then that my combi boiler can just have the CH switch run off one of these, and then the SwitchBot TRVs can all just talk to the hub, and when one or more want heat they can just turn the CH on at the boiler?
I'm not an expert on it all but this seems a pretty elegant setup assuming you don't want a wall panel with controls and be tweaking things regularly... I do like the idea of that with the EvoHome, but not for £1,000 extra cost and what is by now a decade+ old system.
The boiler will ordinarily be turned on by the room stat, which just closes a switch. It might be switching mains or maybe a low voltage line from the boiler.
Either way a relay will work to close the connection, just need to be wary when fiddling if its mains!
I cant see how you could link the trvs with boiler switch without using something like homeassistant or ifttt, though...
Either way a relay will work to close the connection, just need to be wary when fiddling if its mains!
I cant see how you could link the trvs with boiler switch without using something like homeassistant or ifttt, though...
Edited by .:ian:. on Sunday 23 November 17:30
I’ve been reading again and it’s not clear what’s possible.
They seem to infer the single trv and the wall controls can also do this, so the TRVs must be able to send demand requests, and something like a hub can then just pass those on to the relay.
I’ve even seen people use a physical Switchbot ‘switch’ device to push a button on and off for heating
So it’s mostly about if the Switchbot hub can take the ‘demand’ signals and trigger the relay bot.
I’m just assuming all this. If it were that easy why don’t they just say?
Or are they assuming people want it to all be fancy and have it all via an over-arching kit?
If they offered a fancy screen/hub for access with the relay for a few hundred quid so it could standalone it’d still be less than half the EvoHome type setup.
It seems like a no brainer but I feel I’m missing something.
I could buy one, a hub, and a relay, and see if I can get it doing what’s expected on the bench.
They seem to infer the single trv and the wall controls can also do this, so the TRVs must be able to send demand requests, and something like a hub can then just pass those on to the relay.
I’ve even seen people use a physical Switchbot ‘switch’ device to push a button on and off for heating
So it’s mostly about if the Switchbot hub can take the ‘demand’ signals and trigger the relay bot.
I’m just assuming all this. If it were that easy why don’t they just say?
Or are they assuming people want it to all be fancy and have it all via an over-arching kit?
If they offered a fancy screen/hub for access with the relay for a few hundred quid so it could standalone it’d still be less than half the EvoHome type setup.
It seems like a no brainer but I feel I’m missing something.
I could buy one, a hub, and a relay, and see if I can get it doing what’s expected on the bench.
Scrub all this. After reading German reviews on Amazon it looks like this product is a bit weird.
You need a hub but it can only see 10 devices. So having a relay and 18 of these isn't going to work elegantly I don't think.
Why do these companies even bother? What use is one or two of these on a few radiators without an ability to call for heat?
What if your hallway or whatever got hot enough so the heat demand is off, and your room is cold, and you're messing with one of these expecting it to give you heat.
How hard to get off your arse and just turn a conventional thermostatic valve if that's the issue. Afterall you'd not know if it was too hot or cold for you at that moment in time unless you're sat there any way.
Why make such an amazing thing, and then not add support for 20 or 30 of them via a control hub or even just the relay for heat demand, and a phone to set it all up?
Back to looking for deals on EvoHome kit.
You need a hub but it can only see 10 devices. So having a relay and 18 of these isn't going to work elegantly I don't think.
Why do these companies even bother? What use is one or two of these on a few radiators without an ability to call for heat?
What if your hallway or whatever got hot enough so the heat demand is off, and your room is cold, and you're messing with one of these expecting it to give you heat.
How hard to get off your arse and just turn a conventional thermostatic valve if that's the issue. Afterall you'd not know if it was too hot or cold for you at that moment in time unless you're sat there any way.
Why make such an amazing thing, and then not add support for 20 or 30 of them via a control hub or even just the relay for heat demand, and a phone to set it all up?
Back to looking for deals on EvoHome kit.
Their tech support got back to me and said what I proposed would work.
Ie, BT connects everything.
TRVs >> HUB
HUB >> relay (to switch boiler)
Phone >> HUB to set up rules
And each HUB can support 100 BT Switchbot devices so plenty of overhead.
So sink £70 into this and test it out, and then phase out at a cost of about £600-700.
Or go with Evohome for about £1,500 but have a solid trusted setup that won't suddenly stop working because of an app/update issue, or suddenly they want to charge a sub for it or something?!
Ie, BT connects everything.
TRVs >> HUB
HUB >> relay (to switch boiler)
Phone >> HUB to set up rules
And each HUB can support 100 BT Switchbot devices so plenty of overhead.
So sink £70 into this and test it out, and then phase out at a cost of about £600-700.
Or go with Evohome for about £1,500 but have a solid trusted setup that won't suddenly stop working because of an app/update issue, or suddenly they want to charge a sub for it or something?!
I've got a few Switchbot devices (curtain motors, vacuum robot, temperature sensors, hubs, basic IR remote).
They all sort of work, but connection can be very flaky, losing comms for no apparent reason.
Bluetooth range is shockingly poor.
Anything that needs to use a "cloud" connection can be very slow to respond.
If there's an alternative, I wouldn't go for Switchbot.
I've got an Evohome setup, and it has been rock solid for about 8 years now. Expensive, but it just works.
As an alternative to Switchbot, how about Tapo? I've got loads of Tapo devices (smart bulbs, motion sensors, temperature sensors), and they are much more "solid" than Switchbot.
They all sort of work, but connection can be very flaky, losing comms for no apparent reason.
Bluetooth range is shockingly poor.
Anything that needs to use a "cloud" connection can be very slow to respond.
If there's an alternative, I wouldn't go for Switchbot.
I've got an Evohome setup, and it has been rock solid for about 8 years now. Expensive, but it just works.
As an alternative to Switchbot, how about Tapo? I've got loads of Tapo devices (smart bulbs, motion sensors, temperature sensors), and they are much more "solid" than Switchbot.
clockworks said:
If there's an alternative, I wouldn't go for Switchbot.
I've got an Evohome setup, and it has been rock solid for about 8 years now. Expensive, but it just works.
I have EvoHome here too - despite having a small config/commisioning issue this week - I think it is really good.I've got an Evohome setup, and it has been rock solid for about 8 years now. Expensive, but it just works.
As pointed out by another poster - one small issue is it is limited to 12 zones.
I rather hoped that in due course EvoHome II would come out, but the only thing really missing is a larger number of zones.
The controller does get occasional updates over the air - but as it is rock solid stable, I don't think anything has changed for ages.
EvoHome - with the right interface - will do boiler modulation via OpenTherm too. It is a whole league above simple switching.
Honeywell have been in this game for over 50 years.
It sounds like if you’re gonna spend £750, you may as well spend £1,500 and do it right then.
I’ve been eyeing up an EvoHome system for over 10 years, it’s amazing it hasn’t been changed but I suppose the fact it hasn’t is testament to its ‘rightness’
Wrt zones, can any given zone have many TRVs?
I have 15 thermostatic and 3 ‘towel’ rads, but three rooms have two rads so I’m at, err, 12 and 3, so perfect at 15 zones (I’d like to swap bathrooms to TRV too)
Ok I’ll stop looking at the switchbot stuff for the heating stuff. Sounds like it’s a £750 saving probably not worth making!
I’ve been eyeing up an EvoHome system for over 10 years, it’s amazing it hasn’t been changed but I suppose the fact it hasn’t is testament to its ‘rightness’
Wrt zones, can any given zone have many TRVs?
I have 15 thermostatic and 3 ‘towel’ rads, but three rooms have two rads so I’m at, err, 12 and 3, so perfect at 15 zones (I’d like to swap bathrooms to TRV too)
Ok I’ll stop looking at the switchbot stuff for the heating stuff. Sounds like it’s a £750 saving probably not worth making!
Mr Whippy said:
It sounds like if you re gonna spend £750, you may as well spend £1,500 and do it right then.
I ve been eyeing up an EvoHome system for over 10 years, it s amazing it hasn t been changed but I suppose the fact it hasn t is testament to its rightness
Wrt zones, can any given zone have many TRVs?
I have 15 thermostatic and 3 towel rads, but three rooms have two rads so I m at, err, 12 and 3, so perfect at 15 zones (I d like to swap bathrooms to TRV too)
Ok I ll stop looking at the switchbot stuff for the heating stuff. Sounds like it s a £750 saving probably not worth making!
You might want to factor in additional room thermostats as the HR92 temperature measurements are rather localised so it's best to have a room stat say, on the opposite wall in each room/zone. You can use the Evohome Controller as a room thermostat. A cheaper version is the Center 340009; it's rather basic, with no backlit LED, but does the job. I ve been eyeing up an EvoHome system for over 10 years, it s amazing it hasn t been changed but I suppose the fact it hasn t is testament to its rightness
Wrt zones, can any given zone have many TRVs?
I have 15 thermostatic and 3 towel rads, but three rooms have two rads so I m at, err, 12 and 3, so perfect at 15 zones (I d like to swap bathrooms to TRV too)
Ok I ll stop looking at the switchbot stuff for the heating stuff. Sounds like it s a £750 saving probably not worth making!
Our towel rails are on a separate circuit and have standard TRVs, and heated when hot water or any of the zones are heated.
Edited by Somebody on Friday 28th November 23:40
Somebody said:
You might want to factor in additional room thermostats as the HR92 temperature measurements are rather localised so it's best to have a room stat say, on the opposite wall in each room/zone. You can use the Evohome Controller as a room thermostat. A cheaper version is the Center 340009; it's rather basic, with no backlit LED, but does the job.
Our towel rails are on a separate circuit and have standard TRVs, and heated when hot water or any of the zones are heated.
I had eco home and the rooms with rads( as opposed to under floor heating ) were controlled entirely by the temp on the trv which to my surprise was very effective. Our towel rails are on a separate circuit and have standard TRVs, and heated when hot water or any of the zones are heated.
Edited by Somebody on Friday 28th November 23:40
Do you feel you get value for money from these systems? It must take a long time to recoup the cost, at which point the system could become obsolete and unsupported.
I could turn down the spare bedroom when there's no washing drying in there and I could turn down the study most of the time as that's only used for WFH, however, I'd be worried about getting mould if I didn't heat the rooms to 15 degrees or so. Unless you have a big empty house, I can't see it saving a great deal?
I could turn down the spare bedroom when there's no washing drying in there and I could turn down the study most of the time as that's only used for WFH, however, I'd be worried about getting mould if I didn't heat the rooms to 15 degrees or so. Unless you have a big empty house, I can't see it saving a great deal?
AlexC1981 said:
Do you feel you get value for money from these systems? It must take a long time to recoup the cost, at which point the system could become obsolete and unsupported.
I could turn down the spare bedroom when there's no washing drying in there and I could turn down the study most of the time as that's only used for WFH, however, I'd be worried about getting mould if I didn't heat the rooms to 15 degrees or so. Unless you have a big empty house, I can't see it saving a great deal?
I reckon I saved about 20% on my annual heating oil bill with Evohome. As a bonus, it allowed me to fill the tank just once a year, when the price was low. 4 or 5 year payback. I could turn down the spare bedroom when there's no washing drying in there and I could turn down the study most of the time as that's only used for WFH, however, I'd be worried about getting mould if I didn't heat the rooms to 15 degrees or so. Unless you have a big empty house, I can't see it saving a great deal?
I'm still using some of the Evohome kit now, with a heatpump. It turns down the temperature in the bedrooms and lounge during the day, and the workshop and office from 5pm. All temps get increased as soon as the Octopus Intelligent Go cheap rate starts.
I don't use the Evohome "call for heat" function now though, as that messes things up with frequent restarts. The heatpump's own controls handle the basic stuff, Evohome purely looks after the TRVs
Couple of watch outs:
1) Watch out for cloud services going dead. Looking at you, Google.
2) Don't assume just turning individual rooms off will save money - the heat will "leak" to the "off rooms" potentially. Will depend on house setup
3) More thermal mass can be useful, particularly if/when you move to a heat pump (when you want as big a thermal sink as possible).
Heat geek have some good stuff - they basically recommend balancing well and then leaving everything on with a heat pump and using weather comp, as this allows it to operate most efficiently. The same does apply to boilers just the difference is not as marked as you're not getting anywhere near 100% efficiency vs heat pump where you might hit 400% at peak...
I'm currently working out what to do with my Google Nest Protects, and therefore to some degree, my google Nest products as clearly google are getting out of the market. Tado have been mucking about trying to monetise more (VC want their money back I guess), although I don't actually mind paying a sub for the online stuff (how can it be free, constantly, doesn't make economic sense).
Not convinced if we go heat pump I would even need anything smart as it'll basically run constantly in winter in weather comp mode...
1) Watch out for cloud services going dead. Looking at you, Google.
2) Don't assume just turning individual rooms off will save money - the heat will "leak" to the "off rooms" potentially. Will depend on house setup
3) More thermal mass can be useful, particularly if/when you move to a heat pump (when you want as big a thermal sink as possible).
Heat geek have some good stuff - they basically recommend balancing well and then leaving everything on with a heat pump and using weather comp, as this allows it to operate most efficiently. The same does apply to boilers just the difference is not as marked as you're not getting anywhere near 100% efficiency vs heat pump where you might hit 400% at peak...
I'm currently working out what to do with my Google Nest Protects, and therefore to some degree, my google Nest products as clearly google are getting out of the market. Tado have been mucking about trying to monetise more (VC want their money back I guess), although I don't actually mind paying a sub for the online stuff (how can it be free, constantly, doesn't make economic sense).
Not convinced if we go heat pump I would even need anything smart as it'll basically run constantly in winter in weather comp mode...
AlexC1981 said:
Do you feel you get value for money from these systems? It must take a long time to recoup the cost, at which point the system could become obsolete and unsupported.
I could turn down the spare bedroom when there's no washing drying in there and I could turn down the study most of the time as that's only used for WFH, however, I'd be worried about getting mould if I didn't heat the rooms to 15 degrees or so. Unless you have a big empty house, I can't see it saving a great deal?
I might fall in to the big empty house class here - actually, working from home (for myself), so in my office most of the day. I don't need full heat everywhere at that time. EvoHome just gets on with it once I have setup the schedules.I could turn down the spare bedroom when there's no washing drying in there and I could turn down the study most of the time as that's only used for WFH, however, I'd be worried about getting mould if I didn't heat the rooms to 15 degrees or so. Unless you have a big empty house, I can't see it saving a great deal?
As mentioned by others it doesn't have any external dependancies, so it isn't going to go off-line. It does have a phone based application which does conbtact Honeywell's servers - but it is entirely optional and doesn't affect the running of the standalone system.
Personally, I can't see why anyone would have anything that had external dependancies. As mentioned, once the manufacturer gets bored of that product line or goes bump - then it is all useless.
I definately have had big savings AND a better home environment since I went to EvoHome. I started small, with the controller and a few TRVs. I then picked up other TRVs via eBay when they were cheap (buying in the summer seems much cheaper for heating systems!), and adding them to the system.
I also ran the system using the temperature sensors in the TRVs. Worked well - the system seems to 'know' that it is measuring close to the radiator. You can actually set an offset if you need - but I didn't have to bother with that.
Since moving some zones to UFH, I have gone with DT4R wireless thermostats in each room... again, I have a base number of those and am adding when they are on offer.
Pheo said:
Couple of watch outs:
1) Watch out for cloud services going dead. Looking at you, Google.
2) Don't assume just turning individual rooms off will save money - the heat will "leak" to the "off rooms" potentially. Will depend on house setup
3) More thermal mass can be useful, particularly if/when you move to a heat pump (when you want as big a thermal sink as possible).
Heat geek have some good stuff - they basically recommend balancing well and then leaving everything on with a heat pump and using weather comp, as this allows it to operate most efficiently. The same does apply to boilers just the difference is not as marked as you're not getting anywhere near 100% efficiency vs heat pump where you might hit 400% at peak...
I'm currently working out what to do with my Google Nest Protects, and therefore to some degree, my google Nest products as clearly google are getting out of the market. Tado have been mucking about trying to monetise more (VC want their money back I guess), although I don't actually mind paying a sub for the online stuff (how can it be free, constantly, doesn't make economic sense).
Not convinced if we go heat pump I would even need anything smart as it'll basically run constantly in winter in weather comp mode...
The Heat Geek "way" - minimal controls, open circuit - is undoubtedly the most efficient. Best COP/SCOP numbers, maximum heat output for the electricity consumed.1) Watch out for cloud services going dead. Looking at you, Google.
2) Don't assume just turning individual rooms off will save money - the heat will "leak" to the "off rooms" potentially. Will depend on house setup
3) More thermal mass can be useful, particularly if/when you move to a heat pump (when you want as big a thermal sink as possible).
Heat geek have some good stuff - they basically recommend balancing well and then leaving everything on with a heat pump and using weather comp, as this allows it to operate most efficiently. The same does apply to boilers just the difference is not as marked as you're not getting anywhere near 100% efficiency vs heat pump where you might hit 400% at peak...
I'm currently working out what to do with my Google Nest Protects, and therefore to some degree, my google Nest products as clearly google are getting out of the market. Tado have been mucking about trying to monetise more (VC want their money back I guess), although I don't actually mind paying a sub for the online stuff (how can it be free, constantly, doesn't make economic sense).
Not convinced if we go heat pump I would even need anything smart as it'll basically run constantly in winter in weather comp mode...
Is it the most economical way though - heat output where it's actually needed per pound spent?
While some like chasing theoretical efficiency and SCOP number, I'm much more concerned about the size of the bill. Micro-zoning and utilising the cheap rate periods undoubtedly give me lower efficiency, but it costs less to run while still having a comfortable house.
I'd rather save a pound a day than bump up my SCOP by 0.2 or whatever.
BTW, I'm using Weather Compensation mode, with the curve tweaked to suit, and around half of the house is running "open", with the Mitsubishi controls in charge. The other half gets switched in and out as required by Evohome, based on occupancy. Basically 75% is "open" at any one time, and the heatpump goes off at 7:30 pm for 4 hours. Reheated overnight on the cheap rate, whole house "open".
Amateurish said:
I installed my evohome set up 10 years ago and haven't had any issues. I have about 30 radiators distributed throughout the 12 zones plus the hot water. Very reliable.
Spooky.......Mine's been in since 2019 and has been very reliable. But this morning the CS92 hot water tank sensor lost communication and I had to pull the batteries, which were freshly installed 3 weeks ago. Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff