Being able to heat specific rooms via an app....

[R.O.S.S.I]

Hi all.

At the moment I live in a 3 bed semi with a new combi boiler fitted. We don't really use the wireless thermostat time settings as we just turn the heating on and off when we want it.

Recently I've been thinking about how much extra gas we must use heating rooms when no one is in them and also how much of a ball ache it is to keep going round to individual radiator TRV's and turning them on and off (e.g. we dry clothes in our back bedroom with a dehumidifier (or window open)) and thus if we arent drying clothes we don't need the heating on in that room. And we have an office room which is used sparingly so doesnt need heating that much.

Which smart heating systems would be able to do this for me or is there a system I can use which isn't one of the main ones like Nest/Hive that can do this for me? I've never really been bothered about running my heating through an "app" as such and being able to turn it on when im out etc so the house is warm when I get in but if I had the function to be able to turn specific rooms on and off and potentially do this remotely then I might be interested!

Are there any systems that can do this? Can Hive/Nest do this? I'm assuming i'll need to change all the TRVs with some new ones to do it.

 

[glitch]

Recently I've been thinking about how much extra gas we must use heating rooms when no one is in them and also how much of a ball ache it is to keep going round to individual radiator TRV's and turning them on and off (e.g. we dry clothes in our back bedroom with a dehumidifier (or window open)) and thus if we arent drying clothes we don't need the heating on in that room.

How much money do you realistically think it costs you to heat these rooms when compared to replacing all your current TRVs with ones that can be centrally-controlled?

And if you're only talking about two rooms that have occasional use, wouldn't a balanced central heating system being used on a timer basis be more efficient than your current on-demand usage methodology?

 

[Psycho Sonny]

You can do this using Energenie wireless TRV's or honeywell smart TRV's.

What I have to ask you here is how much is your gas bill? Because the TRV's aren't cheap. Plus I find it's far more effective to heat the whole house as it retains heat for longer than only some rooms. As you will lose heat from the rooms your heating up into the ones your not.

The smaller your home is the less sense it makes to do this. The bigger your home is the more sense it makes to buy the TRV's. However like I said they aren't cheap so the bigger the home the more your buying so again it's a huge outlay for so little in savings. You would be better off just walking about your house turning them on and off manually.

Also Dec-Feb are the coldest months so your gas bill will be next to nothing in June, etc. So your savings in reality will only be savings for 3-5 months of the year. They make zero sense as they are so expensive.

It's usually around £50-£60 per radiator. How much is your yearly gas usage and in reality these things save very little like around 10% max.

Your better off buying a smart thermostat. Total cost £200 and pays you back within 2 years whilst keeping you comfortable.

 

[glitch]

Your better off buying a smart thermostat. Total cost £200 and pays you back within 2 years whilst keeping you comfortable.

What's your reasoning behind that statement? Can you show your working out?

FWIW I don't get home automation for heating - it doesn't make sense to me outside of geofencing and being able to 'automatically' switch your heating on/off when your movements fall outside of your normal schedule/pattern.

But I'm eager to see where people are making savings with it and what their ROI is.

 

[Psycho Sonny]

What's your reasoning behind that statement? Can you show your working out?

FWIW I don't get home automation for heating - it doesn't make sense to me outside of geofencing and being able to 'automatically' switch your heating on/off when your movements fall outside of your normal schedule/pattern.

But I'm eager to see where people are making savings with it and what their ROI is.

Take yesterday for example. I was home all day then went out for a dinner party for 4 hours. I turned the stat down an hour before I was going to leave, the system went into eco mode when I left then 45 mins before I was leaving the restaurant I told it to pre-heat my home.

Otherwise my other options would have been come back to a cold house or leave heating on for 4 hours. So I saved at least 3 hours of gas there in 1 day and also came back to a comfortable home. It's the best of both worlds.

It saves money plus keeps you comfortable. I think the 2 year payback is what Nest claim. Real world it's probably going to be 3-4. Depends on your home though bigger the home the bigger the savings I imagine.

http://www.flannelguyroi.com/nest-thermostat-save-money/

this guy has proper figures and he says 1.5-2 years.

Heres where it really works at it's best. What if I had decided after the restaurant to go back to their house? No need for me to have my heating on. So had I done that I could have saved 5+ hours worth of gas and pre-heated my home just before leaving there.

It knows your out and will stay in eco mode until either told to do so or you head home.

 

[glitch]

Take yesterday for example. I was home all day then went out for a dinner party for 4 hours. I turned the stat down an hour before I was going to leave, the system went into eco mode when I left then 45 mins before I was leaving the restaurant I told it to pre-heat my home.

I might be missing something here, but from what you say I can only see one advantage - being able to tell your thermostat to heat your home up when you're heading back.

Everything else would be achievable by turning the heating down/off, which you did anyway?

Otherwise my other options would have been come back to a cold house or leave heating on for 4 hours. So I saved at least 3 hours of gas there in 1 day and also came back to a comfortable home. It's the best of both worlds.

I don't really see your evidence for the additional 3 hours of gas usage. Are you saying your boiler would have been constantly on for all that time? Is your house that poorly insulated that heat escapes that quickly?

And out of sheer interest, is there any data that shows heating a property from cold is more energy efficient that keeping it 'topped up' to a predetermined temperature?

this guy has proper figures and he says 1.5-2 years.

His figures come from assumptions, not real-world data.

I also find some of the data spurious, especially when it comes to comparing a smart thermostat to a non-programmable. I want to see how much a £200+ smart thermostat saves me over a £35 7-day programmable.

Heres where it really works at it's best. What if I had decided after the restaurant to go back to their house? No need for me to have my heating on. So had I done that I could have saved 5+ hours worth of gas and pre-heated my home just before leaving there.

There's nothing 'smart' about turning your heating off - using your example, you could have switched the heating off when you left and then the only advantage your smart thermostat has over a normal one is that it can pre-heat the home.

I'm not knocking the ability to tell your house to be warm when you get home, but I don't yet see the value in the other points you've raised.

 

[Psycho Sonny]

I get what you mean on the 3 hours usage. Yes my boiler switches on and off as and when required. Still all the time I'm away it won't be switching on at all, so the time it's on and gas is being used that is all savings I could never quantify that as there is so many variables. It will use more when it's colder outside, etc. I could turn it on for 6 hours then look at my gas meter at the start and finish of the 6 hours to see what usage is then divide by 6 to get an hourly usage but I can't be bothered tbh.

It's more efficient doing it this way than leaving it on. Probably the most efficient way so that is where the savings come from again even if the savings aren't as good there surely is some savings to me not having it on whilst I was away yesterday.

It's the automatic eco mode and pre-heat which i like about it. Eco mode is when it's saving you money.




"And out of sheer interest, is there any data that shows heating a property from cold is more energy efficient that keeping it 'topped up' to a predetermined temperature? "

Yes there is. For the above scenario heat will always be lost. It's more efficient to turn on/off as required than to leave on.

For example when I leave to go to the restaurant my home is leaking heat. If I'm constantly replacing that heat and it is losing it it's not efficient. Better to turn off and heat it back up once. The topping up method only works if there is zero heat loss in your home.

That is why fridges now come with a holiday mode. Where you can leave the freezer on but turn the fridge off. So for 2 weeks you aren't constantly cooling the fridge. Same concept but in reverse when it comes to heating. No point in "topping up" if your not going to be home for several hours.

 

[glitch]

As an aside, there's a reason why I'm slightly sceptical about smart thermostats, at least when it comes to their ROI.

My parents used to have a on/off timer for their boiler. The heating came on at a pre-determined time, went off at a pre-determined time and the house got as warm as it could during the time the heating was on. Temperature control was switching the boiler off/on via the timer. Pretty standard for a lot of people, right?

I switched the timer out for a Honeywell room thermostat (CM61 FWIW) and almost instantly they started seeing a huge drop in gas usage, which they monitored by checking the meter on a daily basis - something they had been doing for a while before the change of heating control. Parents, huh?

For my parents, a smart thermostat makes zero sense as they very rarely leave the house outside of a pretty regular schedule. But the savings in gas usage they made by switching to a £30 programmable room thermostat were noticeable. And by 'topping-up' the house with bursts of heating where necessary, there's very little interaction needed from them, save changing the target value for the heating on the odd occasion.

Now, it's quite possible they would have made an equal or greater saving with a smart thermostat, but their ROI would have been a lot longer, for obvious reasons. But one thing that really interests me is that they are convinced that the 'little and often' approach to heating a house is more efficient than 'cold to hot' or similar.

 

[Psycho Sonny]

As an aside, there's a reason why I'm slightly sceptical about smart thermostats, at least when it comes to their ROI.

My parents used to have a on/off timer for their boiler. The heating came on at a pre-determined time, went off at a pre-determined time and the house got as warm as it could during the time the heating was on. Temperature control was switching the boiler off/on via the timer. Pretty standard for a lot of people, right?

I switched the timer out for a Honeywell room thermostat (CM61 FWIW) and almost instantly they started seeing a huge drop in gas usage, which they monitored by checking the meter on a daily basis - something they had been doing for a while before the change of heating control. Parents, huh?

For my parents, a smart thermostat makes zero sense as they very rarely leave the house outside of a pretty regular schedule. But the savings in gas usage they made by switching to a £30 programmable room thermostat were noticeable. And by 'topping-up' the house with bursts of heating where necessary, there's very little interaction needed from them, save changing the target value for the heating on the odd occasion.

Now, it's quite possible they would have made an equal or greater saving with a smart thermostat, but their ROI would have been a lot longer, for obvious reasons. But one thing that really interests me is that they are convinced that the 'little and often' approach to heating a house is more efficient than 'cold to hot' or similar.

Well their house is always leaking heat until it hits the same value as outside. Imagine turning the heating off for 2 weeks. That is why smart thermostats tell the heating to come on if it goes below a safe value. Like say i went to Spain for 2 weeks and during that time the weather here hit minus 5. The heating would come on to stop damage to pipes, etc. However if for those 2 weeks the temperature stays above 10C my heating won't come on at all.

Topping up is only efficient if your inside the home or only popping out for an hour or so. Any longer than that and it makes zero sense.

Nest has 3 modes;

Heat where it actively heats, this is when you are home or "pre heating".

Eco Mode - this is when you have left home for a few hours and have a set "minimum temperature" default is 10C but I lowered mine to 7.

Off - This is when you have left home for a few days and have a set "safety temperature" basically to stop your pipes from freezing and damage to your home. Don't know what the default is but I think mine is set to 2C which I believe may be the lowest you can set it too. If I'm in Spain and it drops below that the heating will maintain a 2C temperature within my home.

It switched between the 3 modes automatically or when you tell it to do so. It does it automatically using sensors and your mobile phone, etc.

Again think of a fridge. It tops up with cold when need be 24/7. Do you think it's more efficient to top it up for 2 weeks when your on holiday in Spain or turn it off? Obviously with a fridge you cannot really turn it off when popping out for 5 hours as your food will go off that is why they are left on 24/7. Heating isn't the same principle, it's useless having it on when it's not needed. Therefore if your not going to be home for 5 hours it's inefficient to be topping it up.

 

[glitch]

I get what you mean on the 3 hours usage. Yes my boiler switches on and off as and when required. Still all the time I'm away it won't be switching on at all, so the time it's on and gas is being used that is all savings I could never quantify that as there is so many variables. It will use more when it's colder outside, etc. I could turn it on for 6 hours then look at my gas meter at the start and finish of the 6 hours to see what usage is then divide by 6 to get an hourly usage but I can't be bothered tbh.

You might want to give the meter thing a shot - the results could be very interesting.

It's more efficient doing it this way than leaving it on.

You think, but you don't know for sure. Fair?

Probably the most efficient way so that is where the savings come from again even if the savings aren't as good there surely is some savings to me not having it on whilst I was away yesterday.

I think you are probably right in assuming there is some saving, but I honestly can't say if it would be as much as you (or other people) think it should be.

It's the automatic eco mode and pre-heat which i like about it. Eco mode is when it's saving you money.

What is Eco mode? Something to do with efficiency?

Yes there is. For the above scenario heat will always be lost. It's more efficient to turn on/off as required than to leave on.

For example when I leave to go to the restaurant my home is leaking heat. If I'm constantly replacing that heat and it is losing it it's not efficient. Better to turn off and heat it back up once. The topping up method only works if there is zero heat loss in your home.

But as you say, your house is always losing heat. So if it loses heat at the same rate, regardless of whether the heating is on or off, the question becomes is it more efficient to keep it topped up or to heat from cold?

That is why fridges now come with a holiday mode. Where you can leave the freezer on but turn the fridge off. So for 2 weeks you aren't constantly cooling the fridge. Same concept but in reverse when it comes to heating. No point in "topping up" if your not going to be home for several hours.

Not sure I agree with you there.

The 'holiday mode' on a fridge is so that you don't need to keep it powered on when you've emptied the fridge of most of its contents before you leave. But given your fridge is pretty good at maintaining its temperature as long you don't keep opening the door, it's not really doing much.

The only way you could equate that to a house would be if said house was incredibly efficient at being able to keep the heat in, providing nobody came or left. And that still leaves us with the question of whether 'topping up' is more efficient at heating that home than letting it go cold and heating up on-demand.

 

[glitch]

That is why smart thermostats tell the heating to come on if it goes below a safe value. Like say i went to Spain for 2 weeks and during that time the weather here hit minus 5. The heating would come on to stop damage to pipes, etc. However if for those 2 weeks the temperature stays above 10C my heating won't come on at all.

A £30 programmable thermostat will do that.

Topping up is only efficient if your inside the home or only popping out for an hour or so. Any longer than that and it makes zero sense.

Okay, so assuming that 'topping up' is more efficient in the short-term, at what point does it stop being more efficient than letting a house go cold and then heating it back up again?

Again think of a fridge. It tops up with cold when need be 24/7. Do you think it's more efficient to top it up for 2 weeks when your on holiday in Spain or turn it off?

An efficient fridge only cools when it needs to. And if you're in Spain for a fortnight you aren't opening the door and letting the heat out, so the need to keep the temperature regulated becomes less of an issue.

Obviously with a fridge you cannot really turn it off when popping out for 5 hours as your food will go off that is why they are left on 24/7.

A fridge is at its most efficient when it is not being opened - you could easily leave a modern fridge unplugged and with the door sealed for a fairly substantial length of time without any adverse effect to the food stored within.

Think about when you have a power cut. Does your food really go off in a matter of hours?

 

[glitch]

One thing I think we can both agree on is that spending money on controllable TRVs for each room in your house is a waste of money, right?

Just before we go off on a complete tangent to the OP!

 

[Psycho Sonny]

One thing I think we can both agree on is that spending money on controllable TRVs for each room in your house is a waste of money, right?

Just before we go off on a complete tangent to the OP!

Oh yes definetely. £50+ per radiator is madness to save what £20 a year if even that.

https://www.uswitch.com/energy-saving/guides/heating-on-all-the-time/

When should your heating be on?
One key factor that gets people wondering whether or not to have their heating on all the time, is the idea that it will take additional energy to bring your home ‘up to temperature’ when the heating has been switched off.

It’s clear to see the logic behind this. After all, if you spend a lot of time heating up your home what’s the point of letting it cool down again, just to then heat it all up again.

However, if you leave your heating on 24/7, you will typically end up using more fuel in a like-for-like situation. This is because some heat loss will always occur due to the difference between the temperature outside your house and the temperature you are trying to maintain on the inside.

So, if you have your heating on all the time, your heating system will be using energy on an ongoing basis to maintain the inside temperature.

The greater the heat loss from your home, the more energy you will need to maintain the inside temperature, which means that the cost of leaving your heating on all the time will be especially expensive.

This all means that leaving your heating on all the time will drain a lot more energy from inefficient homes, as the heating works a lot harder to replace lost heat.

That’s why ensuring your home is well insulated and draught proofed is vital to minimise this heat loss. Taking steps to improve insulation is a good way to save on your energy bills - this can include insulated cavity walls, a well-insulated loft, double-glazing and draught proofed doors.

Typically the most energy-efficient approach to heating your home is to programme your heating system so that it comes on when you need it most.

With many of the more modern room thermostats you also have the ability to set different temperatures at different times, and you may even be able to set up a separate programme for weekends.

When you use your boiler timer and room thermostat in combination with radiator temperature controls (TRVs), you really do have the most energy-efficient approach to heating your home.

How to test it
If you have a well-insulated home, you can test whether putting on the heating 24/7 is cheaper than programming your system to come on at certain times of the day.

Heating on all the time

To get a good idea of the energy usage for each option, you can leave your heating on constantly for a week, followed by a week of programming your heating to come on twice a day.

You will need to take a meter reading at the beginning and end of each week, and from the results you will be able to see - assuming the weather and temperature outdoors have been similar across the two weeks - which approach is the most energy-efficient for you.

https://www.ovoenergy.com/guides/en...energy-efficient-to-leave-the-heating-on.html

Well, we believe that the most efficient way to heat a house is to programme your heating system so it’s only on when you need it.

http://www.moneysavingexpert.com/utilities/energy-saving-myths

Should I leave the heating on low all day even when I'm out, or turn it up only when I need it?

According to leading energy experts at the Energy Saving Trust, as well as British Gas, the idea that it's cheaper to leave the heating on low all day is a myth. They're clear that you'll save energy, and therefore money, by only having the heating on when it's required. (Using a timer's best, because your thermostat is designed to turn your heating on and off to keep your home at the temperature you set it.)

The key thing to understand here is that it's all about the total amount of energy required to heat your home.

It's a given that a certain amount of energy is constantly leaking out of your home (though exactly how much will depend on how good your insulation is). So the Energy Saving Trust says if you're keeping the heating on all day you're losing energy all day - and therefore it's better to heat your home only when you need it.


It's the same with a fridge freezer. If you're keeping it on all day your losing energy all day and therefore it's better to only have it on when you need it. that is why the most energy efficient fridge freezers come with a holiday mode. Yes it may be a minimal amount on modern ones but it's still an amount.

 

[R.O.S.S.I]

Fair shout, hadn't taken into account about how it will be better to heat all rooms so the house stays warmer as a whole.

And then just seen the TRV's are pretty damn expensive! Probably won't bother with it then!

 

[Lumeycom]

I did something altogether more ***** that worked out really well for a very modest outlay. My elderly father lived with us for a while so the heating was on almost all day over the cold seasons heating the whole house but luckily our pipework was quite distinct for upstairs and downstairs. All I did was put a motorised valve on the upstairs feed and a cheap timeclock to turn it off in the days so the heating was only on downstairs. Haven't got exact figures but it saved us around £180 in the first year (Old house so gas usage is higher than average anyway)