What would you like to see in evohome? (have your say)

[g6ejd]

You could just install another Controller and use one for upstairs and one for downstairs giving 24-zones maximum and the two controllers can run independent schedules. With more zones upstairs, then you can split a room (en-suite) into two zones and achieve what you need. You probably have upper and lower zones already installed, I'd be surprised if not.

As we know it cost more to heat a house with high humidity, but the Honeywell kit doesn't do any of that, the differential sensing would be a nice addition giving it has access to a reasonable outside temperature reading. I used to have a Nest and that did both humidity and temperature differential, but it never worked that well, well I never noticed it turning the heat down in response to a climbing external temperature.

Overall I am very pleased with my Evohome, I have records that demonstrate it is saving me ~15% per annum based on my 'old' Nest system plus most importantly the house now has a constant temperature in areas where we used to get cold spots. When I walk into our cloak room and it's nice and warm after years of it being freezing it makes me smile with satisfaction, even more so when the hall radiator is off/up to temperature. Zone's are the future

[Edinburgh2000]

As we know it [costs] more to heat a house with high humidity, ......

That is news to me. Can you explain please or point me in the direction of an explanation somewhere else? Thanks.

[g6ejd]

Its the laws of physics:

‘the specific heat capacity of humid air is greater than dry air and humid air will take more energy to heat by a given amount.’

For example one of the advantages of running a dehumidifier is that it reduces your heating costs in winter especially if there is lots of moisture in or entering the home, for example damp washing, showers, etc.

We have a dehumidifier and in the instructions it discusses how wet clothes can be dried more quickly and with significant less energy by placing it and the clothing in a smalll room and shutting the door, it then removes the moisture. It’s a Delonghi unit and takes 0.235Whrrs to run.

[Edinburgh2000]

Its the laws of physics:

‘the specific heat capacity of humid air is greater than dry air and humid air will take more energy to heat by a given amount.’

But that heat has to go somewhere. The heat being put into a house equals the heat lost by it. The heat losses of a house with humid air are surely exactly the same as the heat losses from a house with dry air, through the walls, the roof etc. So even if it takes more energy to increase the temperature of the air up to the setpoint, you get that heat back again as it cools. Having humid air is the same as having a few more bricks in your house (i.e. increasing the heat capacity). So the cost to maintain a house at a steady temperature cannot be dependent on the humidity of the air, over any significant period.

(Sorry to be dragging this thread off-topic)

[victorp1612]

To echo a request a few pages back : I would like my OpenTherm bridge to allow me to set a max flow temperature on my boiler (a Viessmann) effectively
I eventually gave up on this request after getting caught in a ping pong match between Viessmann and Honeywell support teams.

[a62vw]

To echo a request a few pages back : I would like my OpenTherm bridge to allow me to set a max flow temperature on my boiler (a Viessmann) effectively
I eventually gave up on this request after getting caught in a ping pong match between Viessmann and Honeywell support teams.

Did you not set the heat curve and shift parameters on the boiler before attaching the Opentherm bridge?

[HenGus]

Did you not set the heat curve and shift parameters on the boiler before attaching the Opentherm bridge?

The ‘issue’ is Honeywell’s fuzzy logic and the demand for maximum flow temperature (as set in the boiler) profile - TMax Set) when a zone is more than c.2C below its target temperature. The other problem is OT’s demand for c.90C flow temperature when re-heating hot water. Not all boilers restrict this demand to TMax Set. If I recall, the Viessmann sits in this category.

[Technomorph]

If you mean having more than one schedule per zone - that doesn't make sense. A zone is a minimum divisible schedule unit. If you really want different temperatures scheduled in different parts of the same zone, make them separate zones. (Of course then you may run into the 12 zone limit, so that leads into your request for more zones)

If you mean you want the same schedule for HR92's in a zone but to be able to temporarily override one HR92 in the zone without it affecting other HR92's in the same zone - you can already do this by configuring the zone to be a multi-room zone.

In this mode overrides made at the HR92 itself are not propagated back to the controller or to other HR92's in the zone, so they can be individually overridden then will fall back into line with the next scheduled set point change.

There are other differences for a multi-room zone though - each HR92 uses it's own internal temperature sensor instead of having a single sensor for the whole zone. It is intended for use when you have a zone spanning multiple rooms such as a "bedrooms" zone so that each room's individual temperature is measured, but you can use this within a single room as well, especially if one end of the room has more heat loss than the other and measuring locally would be an advantage.

I'm aware of all this. Essentially what I'm suggesting is that a useful feature would be to have sub-zones. For instance, in my master bedroom I have an ensuite and a walk-in wardrobe, each with their own radiator, so three rads in total. Instead of using up separate zones for each, it would be useful to have the option of logically grouping the zones/rooms into Master Bedroom and then being able to control the temp and schedule as a group, or independently. This would keep the interface tidy and provide more granular control. The caveat to this is that I suspect there might be a hardware constraint for the 12 zone limitation which would quickly be exceeded for larger homes. Using two controllers isn't ideal.

Already available. There are already API integrations with IFTTT, Amazon Echo, and many other 3rd party services. With a bit of code its even possible to connect to the API yourself to do your own logging or perform any actions that the smart phone app can perform.

This is wrong. There is no official public Evohome API. It only seems to be open to approved third parties. There is a thread on this site dedicated to reverse engineering the API. There is an official public API for the Lyric thermostat.

[chrisgare]

"Instead of using up separate zones for each, it would be useful to have the option of logically grouping the zones/rooms into Master bedroom"

Maybe I missed the point here. but this is exactly what I have. My single Master Bedroom zone contains three radiators - two in the bedroom and one in the walk-in dressing room.

[Technomorph]

"Instead of using up separate zones for each, it would be useful to have the option of logically grouping the zones/rooms into Master bedroom"

Maybe I missed the point here. but this is exactly what I have. My single Master Bedroom zone contains three radiators - two in the bedroom and one in the walk-in dressing room.

Did you read the rest of the sentence...

...and then being able to control the temp and schedule as a group, or independently.