Smart Thermostat to save money? (Nest/Hive/Tado/et

Hockeynut

I've looked into it a bit, and prefer the look of the Nest one, visually and feature-wise, in particular the learning functionality. I expect this would lead to money saving, probably quite quickly, possibly paying for itself in a year or 2?

We currently have an older boiler (a timeless Ideal classic), hot tank, TRV's, a dial thermostat, and a programmer that can't even set separate day schedules! So it's been on my mind to get one that can be set more appropriately for our usage. That prompted me to look at the Smart Stats.

What I'm interested to know is from anyone who's had these for a year or 2, whether they 'actually have' saved money on their bill due to it?

David

System

Hockeynut wrote: »

I've looked into it a bit, and prefer the look of the Nest one, visually and feature-wise, in particular the learning functionality. I expect this would lead to money saving, probably quite quickly, possibly paying for itself in a year or 2?

We currently have an older boiler (a timeless Ideal classic), hot tank, TRV's, a dial thermostat, and a programmer that can't even set separate day schedules! So it's been on my mind to get one that can be set more appropriately for our usage. That prompted me to look at the Smart Stats.

What I'm interested to know is from anyone who's had these for a year or 2, whether they 'actually have' saved money on their bill due to it?

David

Caveat Emptor - do not believe the quoted savings. They are based on a University test house with no heating controls.

https://www.salford.ac.uk/__data/assets/pdf_file/0012/562989/pdf2-BEAMA-Heating-control-White-paper.pdf

Nest v 3 is both an Opentherm or TPI controller. To use Opentherm, you need an Opentherm-compatible boiler.

OpenTherm
EN12098-5, Controls for heating systems: Start-stop schedulers for heating systems
ErP Class IV (when set up with On/Off control)
ErP Class VI (when set up with OpenTherm control)

So what is Opentherm:

https://theevohomeshop.co.uk/content/21-What-is-OpenTherm-and-why-use-Honeywell-evohome-with-it

So will you save money? The answer is 'yes' but not as much as you think. I had a new condensing boiler installed 9 months ago which is connected to an Evohome smart (all rooms zoned) heating system with an Opentherm connection between the controller and the boiler. My savings are at 15%; however, most of this is, in my opinion, down to the new boiler.

Typical ErP savings are shown here (the % saving is added to your boiler efficiency - note, the lack of anything in double %age figures)

https://www.draytoncontrols.co.uk/sites/default/files/Drayton%20Products%20ErP%20ratings%20June%202017.pdf

I monitor my gas usage every 15 minutes via an optical spot reader. The key thing that I have concluded is 'fiddle with these systems at your peril'. TPI/Opentherm controls are designed to get a house up to temperature quickly (lots of gas used) and then keep the house within a narrow +/-1C range. At this point, the boiler just ticks over. Currently, I have a flow temperature of 56C and a return temperature of 47C - so the boiler is firmly in the condensing range. If I go out for, say, 3 hours and turn the controller to Economy, all zone temperatures drop by 3C. Cancelling Economy then instructs the boiler to go to maximum flow temperature until such times as the house is back up to temperature. Simple logging shows that more gas is used than saved.

In sum, we let our system do its own thing from 7.30am until 10pm. It optimum starts and stops based on outside temperatures, and we leave it alone through the day with the boiler operating in a modulated condensing mode.

[Deleted User]

Also be careful as your smart thermostat controller may need the services of the supplying company to work correctly.
There was a thread here recently about a supplier (OWL) who has made their services subscription only so stopping the thermostat from being controlled externally. You are at the mercy of the supplier for their web services.
https://forums.moneysavingexpert.com/discussion/5743600

Robin9

Ive got a Nest and dont believe it saves money. It may do if it is used to switch on heating for when you come home but you find yourse poo f delayed.

When my old programmer was asked to switch on at 0700 it switched on at 0700 and was up temp at 0800: the Nest set at 0700 actually switches at 0600 so the house is at temp by 0700.

Helen28

If I go out for, say, 3 hours and turn the controller to Economy, all zone temperatures drop by 3C. Cancelling Economy then instructs the boiler to go to maximum flow temperature until such times as the house is back up to temperature. Simple logging shows that more gas is used than saved.

I discovered that as well, what is saved with the heating off for 2 hours is used to get the temperature back up to what it was.

My heating is left on from 08:00 to 23:00 at 21 deg C and uses the same amount of gas as I when I used to switch it off when I went out for an hour or two.

In fact, according to my smart meter, in the evening my heating is only on for 10 minutes or so every hour or so.

My house does have cavity wall insulation, double glazing and 300 mm of loft insulation.

AndyPK

I would be amazed if you got your money back in 5 years lol

It does sound like you could do with a ~£50 programmable thermostat though, where you set different temperatures at different times of the day. And 7 days a week too.

matelodave

I tend to agreee with Andy, I'm sure a basic programmable stat would do the job. six programmes a day for seven days a week must be more than enough for most people.

You can get them for around £50 whereas a Hive or similar cost 3-4 times as much and so I guess will take 3-4 times as long to get a payback.

The Salus S Series is nearly as pretty as a Nest

chib

Nothing wrong with getting a Smart Themostat - they do look very cool. You can't however use moneysaving as a reason to purchase one though.

Blackbeard_of_Perranporth

A basic programmable thermostat is what I have used and continue to use.


Mine is no longer available. This is a good substitute.


https://www.screwfix.com/p/honeywell-t4h110a1021-wired-programmable-thermostat/8672v


Tell Hive to Hive off as well!

matelodave

You can get a programmable thermostat for a lot less than the Honeywell one. Wireless as well. Look here https://www.ebay.co.uk/i/173103223047?chn=ps&adgroupid=52082710721&rlsatarget=pla-379093505267&abcId=1129916&adtype=pla&merchantid=113370289&poi=&googleloc=9050369&device=c&campaignid=973672744&crdt=0 and if you really want a toy that you can play with whilst down the pub to inmpress your mates, there's one of these https://www.ebay.co.uk/p/Salus-IT500-Programmable-Internet-Wireless-Thermostat-Smart-Phone/11003307020