Upgrading Room Thermostats for better control

_OkGo_

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Some background info: We have a new build (2017) with a Heat Pump and A3 rating, although our usage almost puts us in the A2 (unofficially). We use ~6700/6800 kWh/yr for 130sqm, so we are coming in at approximately ~52 kWh/sqm/yr. I think we could easily reduce that by >300 units with better controls

The house is set up with 2 heating zones, upstairs and downstairs, with water controlled separately by the HP controller. Stats are in the sitting room and main bedroom, all other rooms have TRV valves on the rads. As with most HP setups, the system is 'on' all day and the stats control and maintain a steady temperature as they kick in/out.

My problem is with the thermostats that were installed. They are very basic EPH CM 2's with an R27 controller. They are not particularly accurate but I have managed to set them as low as possible through trial and error. The downstairs is set at ~19 °C but really it maintains a 21/22 °C room temperature. Similarly, upstairs is set at 16 °C but maintains 20-22 °C. They are both positioned in suitable positions away from sunlight, draughts and the rads themselves so position is not a problem

I wouldn't mind the offset between the set/actual temperature but my problem is that if I reduce the stats any further they will just stay off and won't heat at all. The house is either at a very comfortable 21/22°C or it cools down well below this. I'd like to be able to maintain a steady 20°C

One further issue we have is that because the main thermostat is in our main bedroom for the upstairs zone, our body heat can maintain the room temperature at night, meaning that stat never drops below the set point and the heating stays off. This means that the other bedrooms cool down considerably more, which is not ideal for the toddlers bedroom.

So my questions are:
- Can I easily replace the existing thermostats with digital versions assuming they are more accurate? E.g. straight swap with EPH digital stats
- Can we easily move the upstairs stat (wired or wirelss) to another room and replace it with a TRV in the main room? I'm fairly handy but I won't touch plumbing
- Are there better systems for controlling (like Nest or Hive) and would these integrate with the existing controller or should I switch that out as well?
 

noproblem

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3,292
OkGo,
There's a chance you might interfere with the set up that's already installed and working well. Your consumption of electricity that does practically everything as regards heating, water, etc, is working out at (in or around) €35 p/w. How much do you expect to shave off that with the changes you're proposing? Not enough to make it worth the trouble I'd imagine.
 

noproblem

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3,292
We use ~6700/6800 kWh/yr for 130sqm, so we are coming in at approximately ~52 kWh/sqm/yr. I think we could easily reduce that by >300 units with better controls

Yes, saw that, but my question was, would the changes and interference with the set up already installed be worth it in the bigger scheme of things. It's all well and good saying you'll save x if you do such and such, but a saving at what cost?
 

Leo

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14,198
There's a chance you might interfere with the set up that's already installed and working well.
The house is either at a very comfortable 21/22°C or it cools down well below this. I'd like to be able to maintain a steady 20°C
It's not working how they want to, so it's perfectly reasonable to explore alterations.

When the options and their costs are known then only the OP can determine whether reduced running costs and more accurate control to their requirements is worth the outlay.
 

noproblem

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3,292
It's not working how they want to, so it's perfectly reasonable to explore alterations.

When the options and their costs are known then only the OP can determine whether reduced running costs and more accurate control to their requirements is worth the outlay.
Indeed. But just making the point about being penny wise, and pound foolish. Sometimes we need to be careful about what we wish for. That's all.
 

Buddyboy

Registered User
Messages
755
I have underfloor heating in the main living room and kitchen. The living room is 65sqM, so pretty big. Originally there were just thermostats fitted, like your setup, and a controller similar to yours. I replaced the two thermostats with programmable thermostats, and set the controller to "on". I set the programmed temperature to various times of day, e.g. 16 degrees at night, and 20 at 9am. It takes around an hour to change one degree, and it does start to work out how soon to turn on the heating depending on future temperature and time. In essence, what I wanted was more control, and not to be heating the room to 20 degrees all night.
https://www.heatmiser.com/en/ are the brand, but they have more sophisticated models now than mine.

It is pretty easy to swap them out, just make sure if it is 12 or 240 volts. And if you are unsure at all, get an electrician.

It's also possible to swap the one in your bedroom. Either with a programmable one or to re-site it. If it's on a stud wall next to the hall/landing, then you could just swap sides. if that is not possible, then it is possible to change to a wireless one. I have used these in the past.
you replace the existing thermostat with a switch receiver, and put the thermostat in the hall.

The thing to remember is all these are are switches, operated on temperature.

So to answer your question, yes, it is possible, and even advantageous, to replace them to get more control. both in terms of location, different heat setttings by time, and even Apps on our phone.

It will take a bit of research though, and I'd start with the Heatmiser site. (I've no affiliation)
 

_OkGo_

Registered User
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394
There's a chance you might interfere with the set up that's already installed and working well.
Indeed. But just making the point about being penny wise, and pound foolish. Sometimes we need to be careful about what we wish for. That's all.
You've missed the point entirely and managed to go off topic with the very first post. The system doesn't function properly because of 2 poorly calibrated stats. I specifically left out cost or payback because it is irrelevant to my questions. But in the scheme of things, 2 new stats would not be expensive.

It's not working how they want to, so it's perfectly reasonable to explore alterations.
Yes, it is this exactly. In the downstairs living space, it is always warm and the stats don't have the control or resolution to drop another degree. And upstairs, I don't want the toddlers bedroom to cool down too much in winter because of a badly positioned stat
 

Leo

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14,198
It's likely that better quality and better placed thermostats might solve the issues here. Is there a location that maintains a more typical upstairs temperature? Perhaps even the toddler's room might be best for now?

Additionally, you can get smart TRVs that would allow you to further fine tune the needs for more important rooms over the course of the day. As you already have TRVs, most of those would be a simple job to replace as the heads are usually interchangeable without releasing any water.
 

_OkGo_

Registered User
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394
Originally there were just thermostats fitted, like your setup, and a controller similar to yours. I replaced the two thermostats with programmable thermostats, and set the controller to "on". I set the programmed temperature to various times of day, e.g. 16 degrees at night, and 20 at 9am.
Thanks @Buddyboy , that's what I am interested in. I probably don't need fully programmable controls but rather just more accurate stats but I will look at them.

It is pretty easy to swap them out, just make sure if it is 12 or 240 volts. And if you are unsure at all, get an electrician.
Not a problem, I have an electrician in the family who can do it for me

If it's on a stud wall next to the hall/landing, then you could just swap sides. if that is not possible, then it is possible to change to a wireless one.
Not possible to swap sides, it backs onto the some dead space between the bathroom wall. If moving entirely to a wireless stat, does the control unit also need to change or get any upgrade/adapters?
 

Micks'r

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178
The programmable wireless chronostat I use is the COMPUTHERM Q7RF. Works a treat, is very accurate and be moved depending on needs.
There are several different types available and should be no problem to exchange once the voltages are matched like for like.
 

_OkGo_

Registered User
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394
It's likely that better quality and better placed thermostats might solve the issues here
Yes that's what I'm thinking, even in the same location, a more sensitive thermostat upstairs would actually respond to a setting of 19 or 20°. Any suggestions for brands or models?

Is there a location that maintains a more typical upstairs temperature? Perhaps even the toddler's room might be best for now?
Any other room upstairs really, the toddlers room would probably be best.

you can get smart TRVs that would allow you to further fine tune the needs for more important rooms over the course of the day. As you already have TRVs, most of those would be a simple job to replace as the heads are usually interchangeable without releasing any water.
How do these work with the existing 2 zone controller? Does it effectively heat independently as a 3rd zone or does the smart TRV still depend on the zone being on?
 

Leo

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14,198
Yes that's what I'm thinking, even in the same location, a more sensitive thermostat upstairs would actually respond to a setting of 19 or 20°. Any suggestions for brands or models?
Drayton are a pretty reputable brand.

How do these work with the existing 2 zone controller? Does it effectively heat independently as a 3rd zone or does the smart TRV still depend on the zone being on?
They will work independently of the controller. What they will just allow you to do is reduce the heat going to certain rooms at times you don't need it. The boiler would still need to be triggered from the main thermostat to call for heat to that zone, they will just allow you to fine tune the heat that certain rooms will get to by shutting down water flow to just the rad they are installed on.
 

_OkGo_

Registered User
Messages
394
The programmable wireless chronostat I use is the COMPUTHERM Q7RF. Works a treat, is very accurate and be moved depending on needs.
There are several different types available and should be no problem to exchange once the voltages are matched like for like.
Great, thanks for that @Micks'r, I was hoping you'd contribute . One further question, does the control panel need an upgrade or add-on to support the RF ?

The boiler would still need to be triggered from the main thermostat to call for heat to that zone, they will just allow you to fine tune the heat that certain rooms will get to by shutting down water flow to just the rad they are installed on.
Perfect, that's what I thought would happen. The zone needs to be on before they takeover, i.e. they are better for keeping rooms cool when the main thermostat is on but if the main thermostat is off, they can't doing anything.

For now I don't think I'd need that level of control and the TRV's we have do a pretty good job as it is. But maybe we'll add it after I've changed and moved the main thermostats as it might make sense for the main bedroom
 

Leo

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14,198
For now I don't think I'd need that level of control and the TRV's we have do a pretty good job as it is. But maybe we'll add it after I've changed and moved the main thermostats as it might make sense for the main bedroom
Yeah, they make more sense in mixed use zones where you might want a subset of rooms heated at different times.
 

Micks'r

Registered User
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178
Great, thanks for that @Micks'r, I was hoping you'd contribute . One further question, does the control panel need an upgrade or add-on to support the RF ?
No, control panel should not need any upgrade. The new chronostat (base unit and wireless controller) would replace the timer and thermostat so just make sure that the new chronostat spec is compatible with the current setup (some setups are powered so check what voltage and others are volt free).
 

JohnJay

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962
I've recently installed a Drayton Wiser system on a gas boiler. I find it very good so far. It allows me to have a separate wireless TRV in each room, so I can control the time and temperature of each room separately. So for example, I only have heat on in the bedrooms between 10 and 11 at night, lots of time to warm the room up, yet they are not been heated in the early evening when they are empty. I have 2 rads in the house that dont have valves (hall and bathroom), so these rooms always heat whenever any other room is on. I also have a main (wireless) thermostat in my hall. It still needs a bit of tweaking, but I like it.
 
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