Would the Drayton Wiser system save money?

[RichD1]

I have a three story detached house which has 16 radiators. Currently we use the Digistat on manual control. The bottom floor is open plan from the diner thro to lounge then sun room and around to the kitchen. There are 5 radiators covering this area, two large ones in the lounge/dining area where we mostly sit at night. The hall and stairs have two rads. The middle floor is not used now the family have left home apart from the family bathroom which has the bath. The top floor is our en-suite which has two rads.

All rads are currently controlled by TRV's, with the middle floor rads turned down to 1. Our current problem is that the living area retains the heat well, whereas the master bedroom doesn't and we find that it is cold when it's time to retire.

My thoughts were to have all the rads on the ground floor fitted with the smart valves and probably a controlling room stat in the lounge/dining area. The bathroom would have a smart valve as would the rads in the master bedroom.

The bathroom rad would only be used as and when needed. The master bedroom probably need to come on about an hour or so before retiring by which time currently the bottom floor is up to temperature and the boiler just comes on ever so often to maintain the temperature in the lounge/diner area so is using very little energy. The controlling temp stat is in the lounge/dining area and the TRV's are almost full on to allow the stat to do it's work.

My question is; when the master bedroom calls for heat later in the evening will the energy used be greater or less than if the whole house was maintained as we currently do. I'm thinking that in the current situation the boiler needs to be on for at least 45 mins to an hour to get fully up to temperature due to the size of the system. If the master bedroom were to call for heat once the system was in maintain mode would the energy needed to heat the additional water be greater than just letting it be controlled by the existing stat.

 

[Swwils]

Ni

 

[ian1182]

I think we need a bit more information. You say there are 16 radiators, can you better explain how many on each floor. For example you said "the top floor is our en-suite which has two rads", is there also a bedroom on that level? Based on what you said, I assume you have a single heating zone rather than separate down & up stairs zones.

In general you should not use a TRV in the room containing the thermostat as that could cause the heating to cut out before other rooms in the house warm sufficiently. Do you constrain the movement of warm air in the house, for example by leaving the lounge/diner doors closed? Any "warm" air on the lower floors should to some extent rise up the house by natural circulation to assist the top floor heating. Is your current programmer set to cut the heating well before you retire? Is the top floor cool during the day/early evening as well?

This may be less a case of smart heating controls vs ensuring the heating is balanced across the house as a whole. That is not to say there could also be advantages of boosting the master bedroom prior to retiring.

 

[RichD1]

Top floor is just our en-suite with the two rads. The middle floor has three bedrooms with a rad in each. There is a bathroom and separate toilet also on this floor with a rad in each. The downstairs is open plan from loiunge/diner thro sun room and around to the kitchen. The doors leading into to the hallway are kept closed. There are two rads in the hallway with none on the first floor landing or the top landing into the en-suite. The house is on one circuit.

The TRV's in the lounge/diner are almost fully on allowing the Digistat to control the temperature. We use the controller in manual mode set to the temperature that we require in the lounge. I don't like using a programmed control as we can vary the time we put heat on depending what we're doing and if we are home.

The problem I believe is that our en-suite does not retain heat like the bottom floor. So by around 8pm our lounge is up to the set temperature and doesn't normally come on again till its time to retire. We set the TRV in our en-suite for around 18c but this falls to around 15c to 16c by the time we go to bed around 11pm.

That's why I started looking at a 'smart' solution.

You'll probably say, why not put the Digistat in the en-suite but that would be inconvenient for manual control.

 

[Mister Banks]

If theres only a bathroom on the top floor then its not an ensuite, its a bathroom. Presumably though there is also a bedroom on the top floor.

The great thing about "smart" heating is the ability to have smart TRV's meaning you can heat individual rooms on different schedules at different temperatures.

 

[ian1182]

Your original question was related to cost saving, I suspect any remediation will be more costly overall. If the ground floor temperature is OK, the middle floor has it's TRV's set low and the top floor too cool when you retire at the moment. I'm still unclear if the top floor only has the ensuite and no bedroom. I am assuming the cost of heating the ensuite today is a modest part of the cost for the house as a whole.

There are pros & cons of a smart solution.

You will have the cost of the Wiser system (£150) plus smart TRV's at £40 each that will soon add up. On the pro side, a smart TRV in the ensuite can be scheduled to avoid unnecessary heating until just before you retire unlike today when it comes on with the lounge. Perhaps you should see a smart heating solution as providing a better balance between the zones (roooms) temperature wise which makes your home more comfortable.

 

[Mister Banks]

Its not recommended to put a smart TRV in a bathroom due to possible issues with condensation. But there's no reason not to have a "hybrid" system utilising manual TRV's in bathrooms, to ensure they are not overheated, and smart TRV's in bedrooms. In my case I don't have any TRV's in bathrooms and I use the main bedroom smart TRV to control the heating in both the bedroom and the ensuite.

As already said there may or may not be savings with a smart heating system but the additional control and comfort I experience in my house makes the expense worth it so far. I have noticed the boiler is firing less than it used to so maybe there are some energy savings as well.

 

[RichD1]

I refer to our master bedroom as an en-suite.

I've never had a problem with the TRV in our bathroom and they've been fitted for over 20 years now. I've got one in our Utility which is quite a small space with no windows and has the dishwasher and washing machine in it and gets a lot of condensation and again no issues with it.

I was originally thinking about modifying the existing system to create 3 or 4 zones. But when I added up the costs of zone valves and some form of smart control plus the hassle of doing the work I thought a smart solution would be probably be about the same cost but a lot easier to install.

 

[Mister Banks]

I refer to our master bedroom as an en-suite.

I've never had a problem with the TRV in our bathroom and they've been fitted for over 20 years now. I've got one in our Utility which is quite a small space with no windows and has the dishwasher and washing machine in it and gets a lot of condensation and again no issues with it.

I was originally thinking about modifying the existing system to create 3 or 4 zones. But when I added up the costs of zone valves and some form of smart control plus the hassle of doing the work I thought a smart solution would be probably be about the same cost but a lot easier to install.

Are they smart TRV's?

 

[ian1182]

It's specifically a smart TRV in a bathroom that I should remembered as being a problem. A regular TRV is not an issue in a bathroom unless it's used as a bypass for the heating system. In my home the bathroom & ensuite radiators heat up when either the HW or CH turns on, hence neither have a TRV.

So when you said 2 radiators in the ensuite, I assume you meant one in the bedroom and another in the attached room. On that basis, a smart TRV in the bedroom which can fire up the heating, a consequence of which means the ensuite will warm as well.

A smart heating system like Wiser gives you the benefit of multiple zones without needing to re-plumb the heating system. So you could easily have 3/4 zones controlled by a combination of smart roomstats & smart TRV's.

 

[Mister Banks]

Its a lot easier to zone with smart TRV's than modifying pipework and installing zone valves.

 

[shadylee]

With wiser and such a big property I would be more interested in the range of signal from the heat hub.

I had wiser at inception, I wasn't impressed with the range.

 

[Mister Banks]

With wiser and such a big property I would be more interested in the range of signal from the heat hub.

I had wiser at inception, I wasn't impressed with the range.

Wiser range extenders would fix any issues, cost about £35 and also provide smart plug functions.

 

[RichD1]

Are they smart TRV's?

Ahh, didn't read your post fully. I could put the smart TRV in the separate toilet adjacent to the bathroom. As the TRV's in the bedrooms on that floor are virtually off then the bathroom would be controlled by the toilet.

 

[Mister Banks]

Ahh, didn't read your post fully. I could put the smart TRV in the separate toilet adjacent to the bathroom. As the TRV's in the bedrooms on that floor are virtually off then the bathroom would be controlled by the toilet.

That would work. I have only had my Wiser system a little over a month so I am still working out the best setup for our house. Its really trial and error IME but I am getting there.