Upgrade Honeywell ST6400 2 zone & dhw with smart thermostat system

[Mister Banks]

Have a look at Drayton Wiser as well. IMO better than Nest and Hive as every radiator can control the boiler individually using Wiser iTRV's.

 

[Andy201]

Have a look at Drayton Wiser as well. IMO better than Nest and Hive as every radiator can control the boiler individually using Wiser iTRV's.

In the end I went for a Tado system, switched out the the two Honeywell wired thermostats with the Tado replacements. leaving the boiler time controller in place with heating now on constant and existing HW control, I did want to replace this unit but not sure of any real benefit other than to remotely boost HW if needed.

I did loads of research, reading lots of reviews and Tado was highly recommended. Nest always seemed to be top but I thought very expensive (especially with needing two thermostats). Tado has learning features that the Hive doesn't and the benefit of the Drayton system with its TRVs calling for heat from the boiler is also a Tado function so seems to be a very good system overall.

Fitted it on Saturday and one smart TRV, a few more ordered to create more zones with individual control, so far so good. Hopefully see some savings and will then buy more. Was relatively inexpensive too; Amazon, selling a wired starter kit for £99 and Screw Fix doing the addition wired thermostat for £80. Smart TRVs from Amazon at £49 too. Should have done it ages ago, I'm quite glad one of my Honeywell CM707s went U/S forcing me down this road.

Thanks all again for your help and advice.