Smart thermostat advice: danfoss tpone-s vs honeywell t6

thrope

I am in a 3 bed, 1.5 storey converted farm property, converted 2004 but quite poorly insulated. We have an new oil boiler and a standard timer with a wireless thermostat.

It all works fine, but with the cold weather we find it takes really a long time for the place to warm up from cold.

I have the heating come on at 4:30 now to have the house up to 18 for 7am. On days we are out at the office I am not sure what to do, I either advance the programmer so its off, coming on at 4pm (for getitng home at 5:30), or set it a setback temp of 16 or 17, but then it again take 1.5h+ for the living room to get up to evening temp of 19-20.

As far as I know the heating is all working properly. I would like to increase the boiler flow temp, but it is at it's max because it is a condensing boiler.

I would like to be able to zone the living room and bedrooms differently, but not sure its worth the cost and complexity of systems with controllable TRVs. Bedrooms we can do fine with regular TRVS. So I am looking just for a thermostat.

So I am looking for a smart thermostat with:

must haves:

- allow different temps at different times, to allow setback temperature of say 12 degrees overnight, so we are never heating up the house from 5-6

- frost mode (to keep at 5 or so if away)

- "intelligent" so that it can automatically decide when to turn on to reach target temp at target time. ie I want to set 18 degrees at 7am and not have to worry about how long it takes to get there, in the winter it will need to start at 4:30, in the spring 6am is fine.

- must function fully without internet connection

- would like to be able to move the thermostat from the kitchen/dining living area in the daytime, to the sitting room in the evening, without this messing it up. Heating is balanced OK so don't think it should mess up what it learns about the house too much.

- control from my phone whereever I am

Budget, under £200

I am looking at honeywell T6 and danfoss TPone-S. Danfoss seems to have 4 stored temps that you can set at differnet times and switch easily between them, and control from phone. So that looks interesting. But the T6 maybe has more flexibility for programming (because I think you have 6 start/stop blocks per day and each can be any temperature, rather than the fixed 4 for danfoss) and maybe better supported (I would think they are selling more than the tpone-s).

Anyone have experience of either of these, or any other recommendation?

Magnitio

I have a Netatmo thermostat which I believe meets those requirements.

thrope

Thanks very much. Does it work well for you?

I'm not sure how much the netatmo is usable if the internet is out (I think you can set the temp manually, but not edit or change timings). Both the honeywell and the tpone are (as far as I understand) completely functional without internet, can set schedules on the device etc.

We did recently change from 4g to fibre so probably the internet is more reliable, and the netatmo does look nice. But my concern is more that I wouldnt' count on any of the servers related to these products still running in 10 (let alone 15 or 20 years), so I think it's better if the device can function stand alone (obviously without phone access then, but the core functionality).

[Deleted User]

As far as I know the heating is all working properly. I would like to increase the boiler flow temp, but it is at it's max because it is a condensing boiler. 

Increasing the boiler flow temperature has the potential to take the boiler return flow temperature out of the condensing zone. The temperature of the return flow must be <56C (Dew Point) for condensing to occur. Boilers are at their most efficient when a low boiler flow temperature is set. 

A new thermostat is not going to resolve your situation but it will give you better control. If a property is slow to reach its set temperature then it means that either the boiler or radiators are under sized (or flow restricted through sludge), or the property is poorly insulated.

I am not aware of any smart thermostats that can be controlled directly from a phone as they don’t contain a SIM card. I have had Evohome in the past and Tado today. Both can be controlled from a smart phone via internet access. The TPOne S uses 2.4GHz wifi.

thrope

Thanks. Yes I understand the issue with the return temperature. But most of the time its under control of the TPI thermostat and the return temps remain very low because it's only firing for a few minutes in every 10 minute cycle. I would happy to sacrifice say 5-10% efficiency for the 1h in the morning if it could heat up quicker, and the rest of the time the TPI ensures average flow is correct for what is needed, and the return won't be too hot. Anyway it isn't possible to set my boiler hotter than 75 (measures 72 at pump when the thermostat stops the boiler firing). I've never seen the return hotter than 53 with the heating on, but of course when the hot water is on heating the tank to 60 the return is obviously hotter so it's out of condensing mode anyway then.

The point is, the heating has enough power, it just takes long to heat up because of the lower flow temperature. If the radiators were sized for 70 degree *average* flow, and my current average flow is something in 63-65 range then they will be underperforming. So the thermostat will solve my problem by making sure the house is the temparature I want at the time I want (I actually don't mind how long it takes to heat up other than its a pain to find by trial and error with the dumb timer as the temperatures change).

I am not looking for a thermostat with a SIM card. I am looking for an internet enabled smart thermostat, whrere the internet remote control part is optional. Ie it can be programmed and set from the device (as well as the phone). Both the honeywell t6 and the danfoss tpone-s allow this. With internet out I would not expect to control it from the phone, but I would like to keep basic functionality.

I find the honeywell product line up a bit confusing in terms of T6, evohome, the new "single zone smart thermostat". But from what I can gather T6R seems closest to what I am looking for, but not sure if this is now an older product not in the current range.

TPOne-S uses RF to the DBR boiler relay, but also Wifi (as optional) to connect from a smartphone over the internet. But all programming and use is possible from the device with no internet connection.

BUFF

I would suggest that Drayton Wiser may also be suitable for your requirements (e.g. schedule is held locally unlike e.g. Tado where it is held in the cloud) but as Dolor pointed out if your internet goes down you won't be able to control your heating from your 'phone whilst away from the house.
Worth a look anyway.

thrope

Thanks, yes of course I don't expect to be able to control from my phone if the internet is out. For me that is sort of luxury add on (to make a change if work plans change), but I would like it to work for people physically in the house (including changing schedules etc.) even if the internet is out.

Drayton Wiser seemed to have much worse reviews (consistently across multiple vendors) than any of the others so I hadn't really considered it. But perhaps that is out of date. I think I would consider the netato - but this seems similar to the danfoss but with only 3 rather than 4 possible temperature modes.  Mostly though I am still  focussed on the honeywell t6r (or other honeywell?) vs the danfoss tpone-s I guess so would be interested to hear any experiences or recommendations with them.

BUFF

Bear in mind that with the T6R you need to be able to plug it into a power socket (same is true for Nest Learning thermostat, I believe that Nest E may work fully on batteries only temporarily ) so it isn't as truly portable as Netatmo/Drayton Wiser/Tado themostats.

I don't know if your oil boiler has OpenTherm for more efficient modulation but the basic Netatmo Thermostat doesn't support it, they have a more expensive modulating thermostat that does.

I have only briefly glanced at the Danfoss TPOne-S but it doesn't appear to feature learning or weather compensation?

thrope

Thanks, it's a good point. The tpone-s also plugs in I think. I thought all the ones that meet the "fully functional offline" criteria and have wifi seem to. But Danfoss also make a tpone-rf with the same device functionality (but no wifi/smartphone) that runs on battery.

In that case maybe Drayton Wiser is the only one that really meets both of those (fully fucntioning offline and battery thermostat) so maybe I should look again. I think it was mostly the TRVs that were poorly reviewed in the Drayton Wiser system but there were enough (relative to the other ones) to put me off. Is it really fully functional offline (ie can change schedule, advance, change temps etc.) or does it just "keep schedule locally" so without internet it will continue on the preset schedule but you cannot make changes anymore?

Oil boilers don't modulate, so no need for opentherm. That's why the TPI thermostat is relatively more important also.

TPone-s definitely doesn't have weather compensation, but I'm not sure how that works. I mean in theory the internal temperature should be enough of a clue of how long it needs to warm up (ie if the house is 6 it will need to start earlier than if the house is 15). I find it is a frustrating market because there is so little technical detail of how any of these things work. It took me a long time to figure out the simple Danfoss thermostat we have now is TPI with a 10 minute cycle that starts modulating when the temp gets to within 2 degrees of set. Learning I am not sure. I'm not even sure what feature that refers to. My understanding was the tpone-s should reach the target temp at the set time so had some degree of learning, but it definitely won't learn my schedule like Nest does. I don't want "learn my schedule" or geofencing, but I do want "acheive target temp at set time so fire the boiler at the appropriate time to acheive that".

I will look into the Drayton wiser in more detail though, thanks again. 

Basically I want the "target temp target time" feature with being able to program multiple temps at different times (for set back overnight). Being able to adapt to flexible working schedule is handy too but the smartphone control seems the best way to address that (put to a setback temperature, turn on remotely when I know I'll be coming home).

Magnitio

thrope said:

Thanks very much. Does it work well for you?

I'm not sure how much the netatmo is usable if the internet is out (I think you can set the temp manually, but not edit or change timings). Both the honeywell and the tpone are (as far as I understand) completely functional without internet, can set schedules on the device etc.

We did recently change from 4g to fibre so probably the internet is more reliable, and the netatmo does look nice. But my concern is more that I wouldnt' count on any of the servers related to these products still running in 10 (let alone 15 or 20 years), so I think it's better if the device can function stand alone (obviously without phone access then, but the core functionality).

Netatmo works very well for us. Initially it would overheat the house i.e. with the thermostat set to 18 the temperature would go much higher and then drop lower before settling down. However it learns the characteristics of the property and becomes more accurate. It carries on working without internet access, but I don't think you can then adjust schedules. The main Netatmo server goes offline sometimes, but it's never caused me any issues. A lot of new tech is very dependant on servers and the companies staying in business. I chose Netatmo because it is a reasonably established  European company and will hopefully provide service for many years. I had more issues deciding on solar, as it was a bigger expense and some of the providers don't give you direct access to controls without going via servers in China.

thrope

Thanks, sounds great. It's mainly about long term support rather than internet access that I'm thinking about. Do you know how the thermostat works? Is it normal thermostat with hysteresis, or does it use time-proportional-integration (TPI) where it fires for a certain amount of time every 10 minutes (ie on 3 minutes in 10).