The Great Thermostat Rip Off

[Ajn]

The general view on this forum appears to be that GSHP and ASHP with UFH should in the ideal conditions be on for most of the time and the room temps set to the required level and not changed.

While I understsand the processes and calculations  involved in heat transfer and heat loss and the time taken to heat a room with low and slow as opposed to high and quick, what I am failing to understand is why I have been sold as "Ideal for control" for my GSHP supplied UFH a set of expensive all singing thermostats with internet connection that I can set any range of setting from anywhere in the world.

 

When the companies commissioning process recomends all the features are turned off and reduced to a basic stat setting am I correct in thinking I have been ripped off?

 

 

 

 

 

[SteamyTea]

1 hour ago, Ajn said:

am I correct in thinking I have been ripped off?

Probably.

 

[ProDave]

The ONLY thing these fancy internet connected thermostats offer is the ability to change the settings or turn it on and off from a remote location.  e,g, if you go away for 2 weeks in winter, then a day or 2 before your return you can turn the heating back on.

 

If you don't want that function then indeed they are a waste of money.

 

To be honest it costs so little to heat our house, I would just leave it on while away.

[TonyT]

Or wire a Shelley across the existing thermostat , effectively just turning it on/off

[SteamyTea]

Heard about this on the news.

Not just the elderly that get caught.

https://www.bbc.co.uk/news/business-15984990

 

[Jymmm]

On 05/12/2021 at 22:09, TonyT said:

Or wire a Shelley across the existing thermostat , effectively just turning it on/off

 

 

This an interesting idea - have you used this yourself ?

 

Looking at their website a 'shelly 1' with the temperature addon module and a DHT22 sensor and you have the basis of a smart thermostat.

Edited December 24, 2021 by Jymmm

[TonyT]

 

No still figuring it out as

my boiler thermostat use a 2 core bus connection, so need to see if there is something I can connect to at the boiler.

 

 

Edited December 24, 2021 by TonyT

[Nickfromwales]

39 minutes ago, TonyT said:

 

No still figuring it out as

my boiler thermostat use a 2 core bus connection, so need to see if there is something I can connect to at the boiler.

 

 

Does it not have a regular stat connection as well as the bus connection? Have you checked the Mi’s? 

[TonyT]

Not sure, winding down at the moment.

it’s a Worcester Bosch sense 2 thing

[TonyT]

Yes it does, need to check it will override the existing stat.

 

 

[Adsibob]

On 05/12/2021 at 20:45, ProDave said:

The ONLY thing these fancy internet connected thermostats offer is the ability to change the settings or turn it on and off from a remote location.  e,g, if you go away for 2 weeks in winter, then a day or 2 before your return you can turn the heating back on.

I think that is underselling it a bit (but not a lot).

In the Tado range for example, it monitors a few things that you might find useful, such as local (ish) air quality, open window detection, and it also has a geofencing feature that I find very useful. And it also uses machine learning to learn how quickly it takes to warm up each room the thermostat is in and then can adjust your settings (if you have this feature enabled ) to not heat up your room too early and to not turn it off too late. But I agree with the general point that in very well insulated houses with low temperature heating systems that work best if the heating is on all the time that these smart thermostats are probably not worth the money.

With our set up, we actually spent almost £800 on a 10 Tado thermostat system because we wanted to have as much control as possible, and as we will be running a gas boiler based UFH we wanted to be as sparing with the gas as possible. Before the works we had a smaller Tado system (about 5 thermostats) and installing the Tado saved us a lot of money.

Now that we will be better insulated, the savings from Tado might be less, but I still think we will save.

 

[Nickfromwales]

19 hours ago, TonyT said:

Yes it does, need to check it will override the existing stat.

You just re-fit the LS>LR link to use bus only.

[JohnMo]

It's bit like weather compensation, if your house is badly insulated it works great, same with all the bells and whistles thermostats.

 

A well insulated house with a fair bit of thermal lag, they just make things complicated, with no real benefit.

 

I had thermostats in all rooms, weather compensation, they were all removed when we started using the heating: as the heating was all over the place.  Now have one thermostat in the hall, spent a few days tweeking UFH water temperature, get the right degree of room temperature under/overshoot.  The whole house sits at 20 deg (+/-0.5), except bedrooms which at 17 to 18 degs (,cool bedrooms is a choice made at design stage).  Now run same temp 24/7.

[joe90]

40 minutes ago, JohnMo said:

It's bit like weather compensation, if your house is badly insulated it works great, same with all the bells and whistles thermostats.

 

A well insulated house with a fair bit of thermal lag, they just make things complicated, with no real benefit.

 

I had thermostats in all rooms, weather compensation, they were all removed when we started using the heating: as the heating was all over the place.  Now have one thermostat in the hall, spent a few days tweeking UFH water temperature, get the right degree of room temperature under/overshoot.  The whole house sits at 20 deg (+/-0.5), except bedrooms which at 17 to 18 degs (,cool bedrooms is a choice made at design stage).  Now run same temp 24/7.

Yes, our Jeremy did the same thing, dumped his complicated weather compensating system fir a single room stat, and I run ours on one.

[JohnMo]

Just got lots of holes to fill and paint, but that's a job for the new year.

 

[tonyshouse]

I have talked about thermostats before saying that they are so C20 

 

in C21 if you even need a heating system then please use a chronostat or programmable room thermostat 

 

as cost is proportional to delta T it costs more to heat all the time and it also costs more and uses more energy than heating to different temperatures at different times of the day 

 

The future is heating regimes not thermostats 

[joe90]

15 minutes ago, tonyshouse said:

it costs more to heat all the time and it also costs more and uses more energy than heating to different temperatures at different times of the day 

But our time lag on heating is so long timing does not work, my heating very rarely comes on so timing does not work, mostly it comes on at night when temps drop and we benefit during the day.

[tonyshouse]

How long does it take to heat up from say 18C to 21C?

[SteamyTea]

43 minutes ago, tonyshouse said:

How long does it take to heat up from say 18C to 21C?

That becomes a bit tricky to work out as it will depend on many things i.e ∆T, current ventilation rates, solar gain, modulating state of boiler/HP.

Best way to test it is to close all windows, vents, put MVHR on low setting, boiler/HP on full/boost and watch the meter and thermometers. But don it on a still night to isolate those variables. 

 

[Ajn]

On 26/12/2021 at 10:58, joe90 said:

But our time lag on heating is so long timing does not work, my heating very rarely comes on so timing does not work, mostly it comes on at night when temps drop and we benefit during the day.

We have found the same. The dark green line on the chart is the UFH feed temp (note: the feed to our "single story annex" bit of 95sqm comes from the main building of 230sqm and I have no control on what the children are doing) The other lines are, grey - Vent extract temp, blue - vent supply temp, light green - vent exhaust to outside temp, orange - vent outside inlet temp.

As an experiment at the moment at night we do a bypass on the MVHR to see if it makes sleeping better. I am a window open man which does not go down well with the other half when we are on the ground floor and only have a patio type door in the bedroom. This period of bypass does not seem to affect the heat loss and its is dependent on external/internal temps to be active.

However I still feel the need for some sort of variable timed control on the UFH as just moving around during the day needs a lower temperature than sitting in the evening and sleeping needs a lower temp still. 

 

On 26/12/2021 at 12:11, tonyshouse said:

How long does it take to heat up from say 18C to 21C?

Our floor takes about 3 hours to take the room from 18 to 21C.

 

On 26/12/2021 at 09:56, JohnMo said:

Just got lots of holes to fill and paint, but that's a job for the new year.

I would not be allowed to remove any of the supplied controls. I can bypass or suplement with as many "toys" as I like BUT if I stop waking up in the morning then the installed system has to be useable.

[JohnMo]

"I would not be allowed to remove any of the supplied controls. I can bypass or suplement with as many "toys" as I like BUT if I stop waking up in the morning then the installed system has to be useable."

 

But that's the point, the supplied control made the system work badly. Huge temperature over/under swing.  Timers would have to set 12 hours offset from time I wanted things to happen. I have single thermostat in the hall (always on), which calls for heat, or shuts off heat.  Bedroom thermostats to make temp lower than the rest of the house, set at 17/18, it works great, they are not allowed call for heat.

 

Set at 19.5, I get a plus or minus 0.5 degree swing, whatever is happening outside.

 

I have no need to mess with the mvhr settings, it just runs at a set speed 24/7, except when boost is on.