Will Smart Raiator Thermostats help reduce my heating bills, are they worth it?

Bigphil1474

Rob5342 said:

Alnat1 said:

Rob5342 said:

We have them in a few rooms and they are great for comfort and convenince. We have the bedrooms set to 18 most of the time so they are cool to sleep in but they come up to 21 for an hour in the morning and even so it's nice and warm when we get up and go to bed. We have the lounge set to 21 during the day but it goes down to 18 overnight.

18C is cool to sleep in? I'd personally want to open the window if the bedroom was that warm or I'd be awake all night.

Lounge is 17.5C in the day, bedrooms around 14-15C. Heating off overnight unless below 0C outside, then it stays on with lounge thermostat at 14.5C which will let the bedroom heat up a bit now and then.

I always find 21 just right if I'm wearing a t-shirt, if it was 18 I'd need to put a jumper on. I can't be alone as the Tado app puts 18 as the lower limit of comfort

A bit on the high side. The legal minimum for a workplace is only 16oC indoors and that's for people sat in an office type place. Someone in bed under a duvet shouldn't need 18oC. Even in the winter, our heating goes off at 9pm and doesn't come on until 6am. It's your money, but for me I'd prefer it to be 18 and wear a jumper than pay for 21oC so i could wear a t-shirt.

Petriix

Bigphil1474 said:

Rob5342 said:

Alnat1 said:

Rob5342 said:

We have them in a few rooms and they are great for comfort and convenince. We have the bedrooms set to 18 most of the time so they are cool to sleep in but they come up to 21 for an hour in the morning and even so it's nice and warm when we get up and go to bed. We have the lounge set to 21 during the day but it goes down to 18 overnight.

18C is cool to sleep in? I'd personally want to open the window if the bedroom was that warm or I'd be awake all night.

Lounge is 17.5C in the day, bedrooms around 14-15C. Heating off overnight unless below 0C outside, then it stays on with lounge thermostat at 14.5C which will let the bedroom heat up a bit now and then.

I always find 21 just right if I'm wearing a t-shirt, if it was 18 I'd need to put a jumper on. I can't be alone as the Tado app puts 18 as the lower limit of comfort

A bit on the high side. The legal minimum for a workplace is only 16oC indoors and that's for people sat in an office type place. Someone in bed under a duvet shouldn't need 18oC. Even in the winter, our heating goes off at 9pm and doesn't come on until 6am. It's your money, but for me I'd prefer it to be 18 and wear a jumper than pay for 21oC so i could wear a t-shirt.

Seems like madness to pay to heat a space rather than wear a jumper! 

Qyburn

One thing I don't think I saw mentioned is that turning down normal TRVs won't switch the boiler and pump off.

That's a bit like we found doing retrofit controls for legacy heating systems, in some cases we couldn't control individual zones but if we created virtual zones with separate setpoint and timing, sometime the whole heating system could be shut down in scenarios where the colder parts weren't actually occupied at the time.

RonRamsgate

BenEdwards said:

So a bit of background.  I have a Baxi Back Boiler, so my first thought is that turning radiators on/off or setting the termostats lower will make no diference (I've been told by various plumers, including one who is a frend, they all the traditional alegid thermostats are good for is turning radiators off or on).

But wondering if using Smart Radiator Switches will help significantly reduce my heating bill.  I would probably use a seperate smart termomiter with them.

The cost of the smart radiator switches is around £40 (whitch is not significantly more than the replacement traditional ones I had to get recently) and the smart thermostats are around £15.

Thoughts?

Its possible to reduce fuel consumption but possibly not your heating bill 

ThisIsWeird

Dolor said:

Petriix said:

Anything that reduces the demand for heat objectively saves you money. Exactly how much and whether or not it's worth it compared to the expense of installing the equipment is a different question.

There's a very lazy tendency to claim that running a boiler to heat a smaller volume of water would be less efficient and therefore cost more; that's a non-sequitur with the first part potentially being true with it being very unlikely (but not impossible) for the second part to be right. The overwhelming likelihood is that a boiler running less efficiently will still use less gas because it's putting out less energy overall.

The picture is very much complicated by subtleties of how the system is configured and used with people often failing to maximise the potential savings through misunderstanding the system.

Smart TRVs are most effective when you have significant separation between the different areas of the house and when they are used. In my house they could work really well because, most of the time, only one room is in use. If we could program it so that the bedrooms got a short blast before getting up and again before bed, that would be a significant saving over heating them whenever the rest of the house is heated. Likewise, only heating the back room while Mrs Petriix is working home alone most days would be better than heating the whole house (including the bedrooms).

I say 'could' because, at £70 each for the 6 TRVs required, it's unclear whether I could make a saving overall. Perhaps if current prices stick around but almost certainly not if they return to sensible levels in the medium term. The entire gas bill for my house (including hot water and cooking) was around £400 for 2022.

My evidence is based on 5 years with Honeywell Evohome (18 smart TRVs). We spent £1500 on Evohome and have saved very little on our heating bill.

BEIS has collated the results from a number of international academic studies. At the end of the day, it is a personal decision whether to buy smart controls.  We no longer have smart TRVs.

Manual TRVs certainly come out well in this. I wonder what setup their achieved energy saving is being compared to? I'm guessing it's pure manual valves, ie ones that are permanently on, and take no account of the room temp.

So, no surprise there.

And most other systems have 'no robust evidence'. 

Dolor, manual TRVs, which according to your report, are seemingly the most effective way to save energy apart from weather compensation, will allow the boiler to keep running, cycling on and off unless a separate interlock shuts it down. 'Smart' TRVs already have that option built in - they can be set to control the boiler to suit demand, so shutting it down when the temp is met.

You cannot possibly be suggesting that manual TRVs are more effective than Smart ones?

ThisIsWeird

Dolor said:

From a BEAMA report last year. Not a smart TRV in sight:

This is 'evidence' of their apparent ineffectiveness? 

BUFF

Qyburn said:

One thing I don't think I saw mentioned is that turning down normal TRVs won't switch the boiler and pump off.

that is the role of the room 'stat(s).
having run a system with a programmer+TRVs but no room 'stat I definitely recommend investing in a room 'stat too - it will pay for itself. 

Sterlingtimes

Situations will differ. We have made considerable savings from using iTRVs.

Here are the problems that we had:

[1] In this large family home, family members forever turned the manual TRVs to the maximum. The temperature was judged by the feel of the radiators.

[2] A north/south temperature gradient. Rooms facing south were hot whilst rooms at the back were cold.

[3] While working from home, gas was turned off during the day and more expensive electricity was used to heat the single room.

Our eight-year average for gas usage is 24,214kWh, and our current 12-month usage is 18,393kWh, a saving of 5,821kWh using iTRVs. More correctly, I would deduct the hot water and cooker usage of 5,821kWh. So radiator saving attributable to Wiser is 13,254/18393 = 0.72, saving 28%.

The system cost £960. 18-month payback is expected. 

[Deleted User]

Sterlingtimes said:

Situations will differ. We have made considerable savings from using iTRVs.

Here are the problems that we had:

[1] In this large family home, family members forever turned the manual TRVs to the maximum. The temperature was judged by the feel of the radiators.

[2] A north/south temperature gradient. Rooms facing south were hot whilst rooms at the back were cold.

[3] While working from home, gas was turned off during the day and more expensive electricity was used to heat the single room.

Our eight-year average for gas usage is 24,214kWh, and our current 12-month usage is 18,393kWh, a saving of 5,821kWh using iTRVs. More correctly, I would deduct the hot water and cooker usage of 5,821kWh. So radiator saving attributable to Wiser is 13,254/18393 = 0.72, saving 28%.

The system cost £960. 18-month payback is expected. 

I agree: that said, most of the above savings could have been achieved with standard TRVs and a band of willing family members. Willing: by way of example. I was previously on the Octopus’ Agile tariff. I could have a bought a number of devices to turn things on when energy was cheap but the family got used to looking at the next day’s prices and doing it themselves.

Bendo

I've had 8 hive smart TRVs for the last 3 or so years.  By themselves,  they are rubbish, I think designed by hive to make you burn more gas.

For the last 12 months I've been driving them with Home Assistant and using a temperature sensor in each room to control them.

Occupied rooms we tend to heat to around 22 degrees,  mainly as the wife suffers from Fibro and it's made worse by cold.

Since using HA to control everything,  we are down from 13000KW gas usage to 10500.

Still got some tweaks to do but can drop that a bit more.