Honeywell Evohome: Control heating of rooms individually, without changing pipework
Evohome: The future of heating is here
We’ve installed over 100 Evohome systems in 2018 alone…..
Homeowners who don’t live in the latest homes, but yearn for reducing their heating and hot water bills, should take a look at Honeywell Evohome – the most innovative heating control system.
Evohome facilitates room by room control of your heating without having to change pipework or add wiring. To enable this, it divides your existing home heating system into 12 zones using radio controlled motorized thermostatic valves.
Since we started fitting this system in 2003*, Honeywell Evohome has proven to be an ideal solution for so many of our customers, in so many different situations.
For example, if you live in a typical British home where insulation and draught resistance are useless, or a listed building where alterations are nearly impossible – Evohome (shown above) can effectively deal with these situations by changing the way you heat your house, bringing the warmth back and saving fuel.
See our video describing Evohome here.
NB: If you are looking for a Evohome user guide, we’ve made one of these for our customers, see the FAQ at the bottom of this page.
What is involved?
By fitting a ‘Honeywell HR92 valve’ (shown below) to every radiator, you can switch to a Honeywell zoned heating system.
If you’ve an underfloor heating system (wet type) in place, we can handle that as well.
With Honeywell Evohome, there is usually no need to change the pipework or boiler. This comes in handy for properties where it is not acceptable to carry out major reconfiguration of pipework for accomplishing central heating zoning.
In addition, no wires to the zones will be required; a radio signal is used instead. The role of the controller is to control all 12 heating zones (and hot water) functions.
Most of the control functions can also be accessed via a smartphone using the Honeywell Total Control app.
We’ve completed 12 zone, 24 zone and even 48 zone Evohome installations, as we can link controllers together for the largest properties.
One of our customers has 5 separate Evohome installations across their properties, including one in St Moritz.
Where have we fitted it?
We have enabled control of small homes, large homes, offices and churches with Evohome.
In terms of what we’ve controlled, just this year we’ve controlled around 4000 radiators, as well as warm air systems, fan convectors, electric radiant reflective ceilings, commercial boilers, domestic boilers, oil boilers, LPG boilers and heat pumps. In some instances we’ve even controlled two or more of the above, all in the same property.
One of our customers has put a 24 zone system in their house, reported a 35% energy saving, and then just had a 36 zone installation put in their own business offices.
- Brings down household energy consumption
- Divides your radiators into individually controlled areas
- Decreases emissions
- Boosts comfort by channelling heating to areas where it is needed the most at a particular instant
- Carries the brand name of Honeywell – the world leader in designing and manufacturing controls
- Allows internet control of every area and hot water
How do the radio signals get around my house?
It doesn’t use Wi-Fi for controlling the heating and hot water within the house, so instead of a 2.4Ghz signal, an 868Mhz signal is used. This lower frequency is not attenuated by walls and obstacles to the same degree as Wi-Fi.
10 bedroom houses are often possible without range issues.
What about the Cloud?
I’m glad you asked that. Recently a number of heating control systems have been launched that store your heating settings in the ‘Cloud’, in other words, somewhere in the internet – but not in your house.
Sadly, in the UK, our internet service relies on telephony companies that have a lamentable reputation for reliability, so the last thing you need is for your heating to be uncontrollable when the WiFi stops working.
Evohome does not rely on stored internet data (ie; the Cloud) and the failure of your Wi-Fi or broadband will, at worst, temporarily prevent access from phones and iPads.
The Evohome controls in your house will continue to work as normal. In fact, we have installed Evohome in places where there is no Wi-Fi allowed, such as NHS surgeries.
What about Nest, Hive, Heatmiser, myGenie, Bosch Easycontrol (to name a few)?
We constantly re-evaluate alternatives to the Evohome system, and it’s fair to say, if we find a better one, we will start fitting it. As far as the others are concerned, there’s some questions to be asked;
- is it just a single thermostat like I had before, with Wi-Fi added?
- can I divide my house into zones (which is the only way to save energy)?
- Do I have to re-pipe the house or the boiler?
- Can I use it to control a fan convector heater, or under floor heating?
- will it monitor the hot water stored temperature in my cylinder?
- What is the track record of this product?
What is the track record of Evohome?
This bit might surprise you. It was launched with more features (lighting, alarm, power outlet controls) as Hometronic in 1996.
Since then, the radio architecture remains the same, but customer feedback in the early 2000s showed the alarms and lighting were unnecessary and added unwanted complexity.
We fitted Hometronic in my own house in Kent in 2003. If you are interested in what this system looked like, we made a video around 9 years ago; Hometronic overview
We still have all the original 26 radiator valves working – but admittedly we have changed the AA batteries a few times since then.
Obviously improvements have been made, the current colour touch panel is simply genius in terms of ease of use. We use this with all the 15 year old radiator valves.
So, at the time of writing, the answer to my question is 22 years.
If it is so good at saving energy, are there any Government incentives?
Yes, if you have it supplied and fitted by a competent, VAT registered firm, you will be charged only 5%VAT on the installation.
Q: I’d like a user guide, ideally a video one.
A: We’ve made one ourselves, see Evohome Operation Guide
Q: My heating installer says it isn’t worth the money and it doesn’t work properly.
A: Not the best advice, perhaps he/she fits bathrooms most of the year?
Q: How often do the batteries last in the radiator actuators?
A: Typically 2 years. Standard AA batteries should be used, not rechargeables.
Q: What wiring changes are needed?
A: All current controls will be superfluous, in other words, timers, thermostats and some cylinder controls. Some rewiring will be needed, this will not normally involve work outside the boiler/cylinder areas.
Q: I see that the Evohome control panel has a 13A plug, why is this?
A: As the controller is marshalling the signals to and from the radiators (and there could be any number of them) as well as the boiler, and perhaps a HW cylinder, it uses more power, and batteries wouldn’t last long. It has a rechargeable battery inside to allow you to move it around the house though.
Q: I get a problem with my thermostatic valves (TRVs) jamming shut after the summer. Surely that will happen with Evohome?
A: This was designed out in 1996 – a cycling function in the HR92 radiator valve opens every radiator valve once every 14 days.
Q: If I get a power cut, what happens?
A: Not a great deal; your boiler will almost certainly conk out with no electricity, so Evohome can’t help you in that regard. When the power is restored, Evohome remembers all the origianl installer set up – and your own settings too!
NB: A point for current Evohome owners is that if the power outage lasts in excess of 24hrs (!), the radiator valves will then go to sleep until 24hrs later. This is to preserve their battery from constantly trying to reach the control panel. You can wake them up early by turning the knob on the radiator valve.
Q: I’ve got a log burner in the lounge, what happens with Evohome?
A: It notices when the lounge is warm and doesn’t bother trying to run the radiators in this zone at the same time. Obviously the other zones carry on as per your schedule.
Q: Who are Residio?
A: Honeywell have decided to split their business units up and Residio is the new trading name for Honeywell domestic controls. This name will start to appear more often during 2019.
Q: Who are Strom?
A: Strom are a UK firm, who are not linked to Honeywell, other than they have a reselling agreement for Evohome through some trade channels.
Q: What is the Honeywell Installer Network?
A: This is trade affiliation scheme where heating professionals can receive training from Honeywell in certain products. Some HIN members are Evohome specialists.
Q: How does Evohome turn the boiler on and off?
A: It uses relays to turn the boiler on and off. When there is a heating demand in the house, Evohome will make sure the boiler starts within around 5 minutes. Similarly when the zones concerned have reached temperature, Evohome shuts the boiler off.
Q: Does Evohome work with any boiler?
A: We haven’t found one that it isn’t compatible with, from Gas to Oil, Electrical boilers to LPG, from 10Kw to 200Kw cascades, we’ve done all these. And electric radiant and underfloor heating.
Q: Does Evohome count as ‘Boiler Plus’ compatible for combi boilers?
A: This is a 2018 regulation that was intended to increase the efficiency of gas combination boilers very (very) slightly. Total waste of everyone’s money for the benefit provided, in my opinion. But the answer is, of course, Yes. Does Evohome massively exceed the savings made by other forms of ‘Boiler Plus’ measures. Yes.
Q: What about OpenTherm? I’ve heard that is a modern variable boiler control?
A: Most of us can switch off now…. as it is not relevant for most UK boiler systems.
OpenTherm is a protocol that is open for use across all manufacturers; it was ratified around 1996 (so it isn’t new, unlike some pundits on forums seem to believe) and was intended to allow heating controls to work closer with a boiler’s internal settings. Evohome can be used with an OpenTherm boiler, using an accessory part.
Most UK domestic boiler manufacturers do not support OpenTherm connectivity; however the likes of Ideal, ATAG, Intergas do.
It is allegedly possible to hack models of Worcester and Vaillant boilers to work in OpenTherm mode, because many of their close derivatives sold in mainland Europe have this functionality, but this will invalidate your UK warranty for almost nil benefit! Not something we would get involved with.
Q: How many radiators can be connected to Evohome?
A: Your house would not be big enough! We’ve done systems with 80+.
Q: How many zones is the maximum?
A: Each control panel can control 12 separate zones of heating (but a virtually unlimited number of radiators) and one Hot Water cylinder.
There’s nothing to stop you adding additional control panels to get to 24 zones, or in our case, 48 is the most we’ve done in one property so far.
Q: I can’t connect my Evohome panel to my Wi-Fi router? It isn’t found on the Wi-Fi menu?
A: Your installer should complete this bit for you, we do.
Firstly, make sure the panel has been connected to the mains for about an hour once you have got it out of the box, so the battery voltage is up.
As technology moves on, router manufacturers get caught up in a speed race. Modern units can work in 2.4GHz and 5GHz modes, Evohome is on 2.4GHz only. Furthermore some of the more leary routers offer data rates at 2.4GHz not supported by the Wi-Fi alliance. In other words, if your router has been set up to work outside the defined standards, Evohome may not be able to connect to it. We’re not experts on Wi-Fi routers, by the way.
Q: What goes wrong with Evohome?
A: Very little.
We’ve an installed base of around 500-600 units, and in the last 5 years we have only changed one control panel, and that was during the installation process.
The radiator valves are very reliable, you should change their batteries when advised on the screen, as like any battery product, leakage will corrode the contact strips. Don’t get the radiator valves wet, as it gets under the display screen.
The hot water sensor box also has 2 AA batteries inside. When these get old they can adversely affect nearby radio communications, so if you ‘lose’ some radiator valves, in the first instance, change the hot water sensor batteries!
Q: How does Evohome monitor and control hot water?
A: If you’ve got a combination boiler, it doesn’t.
For everyone with a hot water cylinder or heat store, Evohome will display the temperature of the stored water on the control panel – which is really useful if you’ve come home and want a bath. If it is showing 22ºC – your wife has already used it all up.
It does this by using a temperature sensor that your installer fits to the hot water cylinder, and this is linked by radio to the panel. Please note that if you have an ‘unvented cylinder, aka Megaflo’ your installer will have to preserve the original electrical safety controls that came with the cylinder when the system is wired up.
Q: Do I need a Evohome HR92 electronic valve on every radiator? I can only afford 6 and I have 18 radiators?
A: Wait till you can do them all. Otherwise, whenever any of the 6 HR92 equipped radiators come on, in this scenario the other 12 will waste heat at the same time. Which rather defeats the object.
Q: Do I need a Honeywell valve body on my radiator in order to fit an HR92 electronic radiator actuator?
A: Strictly speaking, no. TRV brass bodies by Myson, Drayton, Pegler (not an exhaustive list) are compatible.
However, all non-Honeywell TRV bodies have a different spring tension on the pin, and a different ‘stroke’ ie: distance from fully open to fully closed. Whilst the HR92 will sense this, battery life is optimised when using Honeywell valve bodies. No surprises there.
Q: I’ve read/seen on YouTube that I can get the valve to calibrate to the radiator valve it is mounted on, if it is not a Honeywell one.
A: Every time you remove the HR92 from a radiator, it recalibrates soon after you refit it, saying CYCL on the display. It has to do this because you may have fitted it to a different radiator, so no calibration is needed from you.
Q: I’ve another question that isn’t covered here?
A: If it helps us install more Evohomes, I’ll publish it here. Email me.
Ask us for a free on site demonstration.
See our blog for examples of real life installations