Quest for lower heating cost, Smart thermostats / TRV's (HIVE)

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RBailey
Posts: 86
Joined: Thu 1st Aug, 2019 7:25 am
Location: Rutland

Quest for lower heating cost, Smart thermostats / TRV's (HIVE)

Post by RBailey » Fri 23rd Oct, 2020 9:22 am

Hi All,

I thought I would share some experience of my recent change to a “smart” central heating controller and the quest for lower energy bills.
We have a large house, consisting of three cottages and a barn knocked together, one boiler down one end, 15 radiators and the thermal insulation of a typical stone on dirt period property, i.e. none.
I have therefore opted to fit a HIVE system (British gas / Centrica) but there are other systems out there.

The HIVE system (for heating) is a two phase system.

Part 1 – Thermostat replacement.
This replaces your traditional thermostat or thermostat / timer combo for both your central heating and gas hot water (but not electric immersion heater).
It is a simple plug and play wiring replacement for your thermostat and the controller temperature sensor is a wireless unit that you can put anywhere.
There is also a sophisticated app for your phone to control the schedules of times and temperatures.
This is good, and a simple upgrade, but it still only controls ALL of your heating on/off/temperature. The key being, all, if you switch heat on the whole house heats up.

Part 2 – Smart TRV (Thermostatic Radiator Valves)
These are wireless controlled valves that fit in place of the inlet valve or traditional wax TRV.
Image
The HIVE TRV’s sense the room temperature and you can individually open the valve and switch on the boiler.
This means that you can heat different rooms to different temperatures at will.
Via the app you can then set different rooms to run at different temperature and times.
For example, master bedroom heats up at adult bed time, the children’s rooms at their bed time and the study during the day, with the heating off (or set to 10C for the rest of the day.
Image

Wireless
The system runs on a zigabee network so you need a box to link it into your wifi system. However, you can also get plug in zigabee signal boosters (from HIVE) so you can get a signal all over the house. This ability to boost / extend the signal was important to us due to the stone wall thickness.

Cost
The main controller, including fitting (which I thought would be difficult, but I now know is easy and was bodged anyway) was a fixed £250 from British gas. This was a lot cheaper than the Honeywell system I looked at.
The smart TRV’s are about £50 each which mounts up fast but none of the other systems are that cheap either. I also had to change all the valves as they were so old they were not physically compatible but they may also have been seized so not such a bad thing.

Problems
The early HIVE TRV’s got a very bad reputation, and the control side is still not that logical and a bit glitchy. The official support isn’t that great but the online support community is good.
I also think some users expect amazing results and moan when there room isn’t hot after 5 minutes of calling for heat. I am realistic to know I will never win the heat battle but I just hope to reduce the attrition rate.

Saving
HIVE do not guarantee any savings (some brands do) but I can not help but think that just heating the rooms I need has got to be a saving.

So far I am happy. A lot of control and just to have a warm study you do not need to heat the whole house is great.

Hope this is of interest or helps someone.

Cheers,
Richard B.

P.s. This is not sponsored, wish it was given the cost of the valves! I just thought I would share to prompt any discussion or questions.

paulc
Posts: 344
Joined: Sat 22nd Oct, 2016 7:05 pm

Re: Quest for lower heating cost, Smart thermostats / TRV's (HIVE)

Post by paulc » Fri 23rd Oct, 2020 12:12 pm

Have contemplated getting "smart" TRVs for my radiators. Would only need six or seven, but even so, that is a sizable outlay although there are one or two cheaper models out there (think I've seen some at around £30). Aside from flat batteries, my main concern is communications - Do the TRVs signal back to the controller when they have reached temperature or is a thermostat required in each room ?

RBailey
Posts: 86
Joined: Thu 1st Aug, 2019 7:25 am
Location: Rutland

Re: Quest for lower heating cost, Smart thermostats / TRV's (HIVE)

Post by RBailey » Fri 23rd Oct, 2020 12:42 pm

Each smart TRV has its own thermostat built into it which it relays to the controller.
(Hive even has two stats in each TRV so it can do some math's to extrapolate the room temperature from the radiator temperature).

Be aware that some of the cheaper systems will only act as a semi-smart TRV and will not switch the boiler on and off.
If you want a fully customizable schedule you have to be able to switch the boiler on and off, otherwise you will need to run the boiler 24/7 so there is heat when the TRV asks for it.

I know that these systems are a chunk of cash but so is our gas bill :roll:

I "think" (so be warned it could be twaddle) that smart TRV / heating controls count as part of the tier 2 in the energy grant system that the government announced. If you spend on tier 1 (loft insulation etc.) then you can get equal cash grant for tier 2.

paulc
Posts: 344
Joined: Sat 22nd Oct, 2016 7:05 pm

Re: Quest for lower heating cost, Smart thermostats / TRV's (HIVE)

Post by paulc » Fri 23rd Oct, 2020 1:45 pm

My home automation system switches the boiler on or off subject to heating schedule (temperature & time), and also for hot water. As long as the TRV can signal the state (either open or closed) or temperature, it is just a matter of editing a configuration script for the H.A. Don't need any real "smarts" in the TRV.

Having looked at this Green Home thing, I've come to the conclusion that it is little more than political spin that doesn't really help the majority. Boosting loft insulation levels isn't going to cost me much (less than £100), the other primary options have a payback of 20-100+ years. Certainly not going to allow any government "approved contractor" access to my control system - He probably wouldn't even know how to access the config files let alone be competent enough to make any changes.

Feltwell
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Location: Shropshire, England

Re: Quest for lower heating cost, Smart thermostats / TRV's (HIVE)

Post by Feltwell » Fri 23rd Oct, 2020 1:59 pm

Interesting, thanks for posting Richard. I'd dismissed them as "I don't need to switch heating on from an app on my phone" - but what you show there is it does a lot more, particularly the ability for each TRV to call for heat.

If you can find a way of fixing a teenage daughter who likes to have her bedroom TRV set on maximum (I was cold yesterday and I forgot...) whilst simultaneously leaving her bedroom window open (I was hot....) - when she has an attic room so lets lots of heat out of the house - that would be brilliant :roll:

Ohh yeah, and get a teenage son to open his bedroom blinds (BUT the light shines on my compute screen!) - honestly he is the Prince of Darkness.

RBailey
Posts: 86
Joined: Thu 1st Aug, 2019 7:25 am
Location: Rutland

Re: Quest for lower heating cost, Smart thermostats / TRV's (HIVE)

Post by RBailey » Fri 23rd Oct, 2020 3:10 pm

Feltwell wrote:
Fri 23rd Oct, 2020 1:59 pm
If you can find a way of fixing a teenage daughter who likes to have her bedroom TRV set on maximum (I was cold yesterday and I forgot...) whilst simultaneously leaving her bedroom window open (I was hot....) - when she has an attic room so lets lots of heat out of the house - that would be brilliant :roll:
If the TRV is manually overridden (which you can do easily on hive just by turning the top) it only "boosts" the temperature until the next scheduled change so it can't be changed for that long.
There is also the ability to give family members different levels of access to the app.

All our children's rooms on have automatic door closers fitted. Otherwise they "forget" and the cats get into their bedrooms but they are also good for heat control.

I also highly recommend a smart plug for the kids TV / PlayStation, "Alexa, kids TV off" works miracles! I can also time and lock internet access via the router software :twisted:
Feltwell wrote:
Fri 23rd Oct, 2020 1:59 pm
Ohh yeah, and get a teenage son to open his bedroom blinds (BUT the light shines on my compute screen!) - honestly he is the Prince of Darkness.
I think you can even get smart window blinds from Ikea :lol:

a twig
Posts: 607
Joined: Sun 6th Oct, 2013 10:18 pm

Re: Quest for lower heating cost, Smart thermostats / TRV's (HIVE)

Post by a twig » Sat 24th Oct, 2020 11:40 am

We have tried both Hive and Evohome across two properties. Hive is great for our rental as it allows us to schedule lighting etc while the place is empty, but at home we have the Honeywell evohome.

It's a similar set up but just does heating (no smart plugs etc) we chose Evohome because the "hub" has a touchscreen which can control everything, so it still keeps full functionality even when the internet is down, whereas the Hive will only continue to run whatever settings it was last sent from the app, you won't be able to adjust until your internet comes back up.

The Honeywell TRVs are a bit noisier than the Hive ones, so if you're a light sleeper you may want to set your schedules accordingly, but other than that it has been brilliant, to the extent that we are installing it into our new house as soon as we move in.

Bills dropped by ~£20 a month, and house generally a lot more pleasant/comfortable to live in. The Honeywell TRVs also has a feature that detects if you leave a door or window open and will shut off the rad until it is closed so you aren't heating the outside! Battery life has been great, over 18 months now in 2 AAs, and still 2/3 charge remaining.

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