[OpenTRV-dev] Comments please! FAQ (and wiki), forum and shop

Damon Hart-Davis dhd at exnet.com
Thu Dec 22 09:50:46 GMT 2016

> I realise we're in early stages, not a full production run, these are dev releases etc - but It is just me that's a little surprised at this pricing?
> I'd understood the aim was to hit £10 for a brand new valve at retail, so £45 for non-perfect presumably un-waranteed unit seems quite a long way from that, and actually more expensive than (say) the evohome valve. I guess there's still an argument there that the OpenTRV's light sensor will produce a bigger saving than the evohome (and open source is a good thing, albeit not something I think many end-users will care much about), though arguably the evohome has some nice features that OpenTRV is [currently] missing, like full 2 ways comms.
> Is the original £10 per valve that was talked about still considered realistic?

With movements in exchange rates etc we think that £15-ish is a more realistic long-term goal now.  The core aim is to allow financial payback in one heating season so that (for example) renters with typical 1-year tenancies can afford OpenTRV valves.

Note that all of the TRV1.x valves that will appear in the shop have been assembled and reassembled several times, eg by yours truly, so the actual cost to us is much higher than the shop prices.  We want to let devs play with these things ASAP so this was our best effort at picking a ‘fair’ price that at least covers hardware costs to us.  We do totally understand that this is not for everyone.

You make a good point on warantees: these indeed are not new consumer kit, but if something arrives from us apparently DOA, we’ll do our best to sort you out.  We may offer a pile of salvage boards with no promises at all, later, but that’s a separate issue.

There’s still a lot of work to do on cost reduction of the hardware, including a probable port to a cheaper microcontroller and other cheaper parts.  In fact I take that to be the biggest technical and engineering job to be done.

I’m also hoping that devs will help us scrutinise and improve the energy-saving algorithms, for example.  Here’s a little taster of one of the graphs I use when tuning the code (algorithm responses to real light levels as reported by a valve in a rather tricky room):




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