bargains to be made on amazon and darty – nest thermostat 2nd generation !

21 Jan

although in French, igen site is pointing put that Nest thermostat 2nd generation, understood to be EOL, is on sale via amazon and darty. at those prices, this is a real bargain!

time to re open threads around rc840 !




Nest thermostat has made it to Darty!!

21 Sep

look the Nest thermostat for sale at French retailer Darty!


What an amazing step,

Nest making it into French market, for sale at Darty!

Congratulations to the Nest team, well done and loads of success!

Good Month of April according to my nest report

13 May


Now all i have to do is begin computation of that saving in energy achieved…what about you guys in Europe? What report do you get?

Nest thermostat 3.0.6 update? anyone in Europe?

19 Apr


there is supposedly a 3.0.6 software update available for Nest thermostat users (heating only mode)…. somehow I am not able to get this yet on my nest.

Can anyone having “heating only” mode setup, share their experience in getting 3.0.6 please?

Since Nest thermostat is not officially supported in EU, I am not expecting much support from the US, just curious…

some of you may say that winter is behind us (which I really hope)… somehow, my heating system did turn on this morning..





for sale 1 pack – thermostat nest 1st gen & RC840T-240

10 Apr

hi all,

as you’re familiar with my blog, you know I am the proud and happy user of a Nest thermostat.

I have had a 2nd yet brand new in its box Nest thermostat (1st generation) seating doing nothing.

I have also a few other RC840T-240, so I have decide to put a “complete pack” for sale on ebay.

the auction starts tomorrow morning April 1st 2013 and there is another 24h before it finishes!

happy bidding,


photopack nest et rc840t ebay

my natural gas consumption as it stands…

30 Mar

Hi all,

I don’t actually really know how many of you do walk by this blog, nor how frequently you’re checking on new posts.

although the graph below has French content, I wanted to share with you my 2012 gas consumption (quantified in terms of kwH) and the 2013 one “as of today”.

Note this is prior to the installation of the Nest Thermostat. Please note the following facts regarding our apartment:

  • building from 1930s, with 3 sides “exposed”
  • apartment located on the 2nd and last floor (15cm/2 inches of insulation made of cellulose wading)
  • however the attic itself is not insulated
  • cast iron radiators equipped with thermostatic heads
  • the apartment is about 62m2 (~667 sq ft) and our ceiling is at 2.8m (9 ft 2 inches)

natural gas consumption 2012 2013

what about yours?

I have gone back in time and I can add the last few years on different chart (note that 2013 is partial at this point of course – note that my year counts from October to Octobers):

  • it is too early to say how much Nest is bringing in terms of saving,
  • to be noted that this winter appears to be particularly “cold” and lasting a long time.
    • I will quantify this and number of days below 18degC (64F) within the period.
    • I will also explain the reason why this decline overtime – I have installed insulation (summer 2009) , thermo-mechanical valves (summer 2010?)…
    • Last but not least, I have moved a cast iron radiator location in my living room (summer 2012),
    • and insulated my daughter’s bedroom from the inside (summer 2012)

Nest thermostat with Baxi caldaia murale – natural gas heater with Perri Termostati a 220 240v thermostat

12 Feb

edited on Feb 12th 2013 – futuristic views included

following a request from Massimo a Nest thermostat potential adopter in Italy,

I am trying to assist him in what could be the ad-hoc wiring of a Baxi gast heater mated to a Perri Termostati, a 220 240 thermostat.

the two thermostat wiring options are shown below:

perry thermostat TE120 TE121 TE122 TE123
elettronic termostati perry italia

elettronic termostati perry italia

in my opinion, the “red” boxed wiring (if compatible with the Baxi heating unit) is preferred.

Massimo having now confirmed his wiring is not the red box above, but rather the separate circuitry of supply and dry switch as shown below:

with_separate_power supply_dry_switch_eletronic_perry_TE120_TE121_TE122_TE123_termostati_elettronici

…I am starting to think about how is the actual wiring done at the heating unit level – my point being that I do not believe the actual wiring per Massimo’s feedback

is as shown below (from the Baci user manual):

baci wiring as-is_inclusive of power supply_termostati_elettronici

section added on Feb 12th 2013.

so given the status reach previously, here is below what I would advise one may want to setup in order to make the Nest Thermostat work with a heating system not providing both line and neutral.

Please note that my preliminary conclusions are that the RC840T is not per-say compatible as-is.

baci thermostat nest wiring prosposed

baci thermostat nest wiring prosposed

Now if we want to get a notch more futuristic and ask Nest Lab a serious ease of implementation with “most” heating systems in EU (at least the ones working on 220 240 volts), here is what a good step forward would be….

the futuristic nest thermostat 20130212

I just want to point that this version of Nest thermostat does not appear to exist today, but it should not be that complicated to roll out for the European market.

what do you think? Do you concur?

quick survey regarding your current thermostat operating voltage

28 Jan

map of nest thermostat location relative to gas heating system

16 Jan

Good evening to all,

I said in my previous post, since we have been talking a lot about wiring and electrical aspects…

at some point comes the “routing” of all those connections. Below you can see if my apartment and

the three key area of interest: the heating system location, the breakers box and last but not least my nest thermostat location.

A couple of comments:

  • all rooms are fitted with cast iron radiator
  • each cast iron radiator is fitted with a thermostatic head to the exception of the so-called “Bedroom 2” where the thermostat is located (for obvious reason)

the idea is to regulate the coldest room to whatever temperature I need and let all the other room (warmer in general) get settled via their individual thermostatic heads.

All I can say even before the Nest this setup worked pretty well – but the smartness of Nest is likely still to bring energy savings (hence dollars, Euros or whatever your currency is – I am flexible). the only issue I know with this setup, I will likely have is the auto-away feature not working well given the location of the thermostat (comments are welcome as usual).

nest thermostat appartment

Current plan:

– to wire my nest thermostat to the breaker box where the Aube RC840 unit will be located (this requires 3 wires, W/R/C)

– wire the aube RC840 to the Gas heater (this requires also 3 wires Ns/Ls/Lr).

Alternative plan:

– I may place my Aube RC840 right next to the gas heater (in case I struggle to add an extra wire – see my previous post)

– route W/R/C wires to the “breaker box” and then dispatch them to the nest location by means of proper “jumpers”

wiring nest thermostat aube rc840 heating system

I have full flexibility when it comes to the number of wires to be run from the green box (the breaker’s box)

to the Nest Thermostat, however, I am missing 1-wire from the green box (the breaker’s box) to the gas heating system (blue).

As a side comment, a Neutral/Line/Earth are also needed to supply the Gas heating system (hence the 6 wires needed)

talk to you guys soon, any feedback? questions? critics? candid feedback is always welcome!

missing 1 wire from my gas heater to my Aube RC840 to finish off Nest Thermostat wiring!!!

11 Jan

Dear all,

have verified in full my previously recommended wiring  earlier this week – having a 3-wire (220 240 Volts) cable running from my gas heater, to my RC840, and 3-wire from my RC840 to my nest thermostat.

While doing this, I have actually used this to let me Nest get fully charged, updated to the latest software, and exercised it a bit.

A few comments for those who go thru this process:

  1. it took a few hours to get my nest battery charged up to at least 3.7V
  2. note that in between it may (at least mine did) reboot a few times – realizing it does not have enough energy to run wifi (required to get the update done – have no idea about the size of the download by the way, do you?)
  3. 3.7V is critical as it is the minimum Nest needs to be able to launch software updates
  4. once update was done, an easy trouble-free process, I was able to fully control my nest via my Ipad

I live in an 1930s building, and our apartment got renovated to the current Electricity standard a few years ago (meaning I have a decent amount of extra wires running thru the various electricity access). Frustration rose when I realize I did NOT have a 220 240 Volts with 6-wires but 5-wires!

This means I can’t properly wire the Ns/Ls/Lr from my heating unit to the RC840T (I had planned to locate it near my fuse box – opposite from my heating unit).

So I have paused my installation – and – it looks like the only alternative is to change the heater supply cable and upgrade it to a 6-wires one.That’s assuming of course, I have room to retrofit it!! If you can think of anything else to do… please chime in now!!

In any case, I have updated and confirmed now that the diagram below is fully working.

nest thermostat 220v rc840

if you can’t figure out how is laid out the apartment and how the wiring has to run, I will draw up a schematic of the flat and the way the wire will be running thru.

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