How safe are HR92 (radiation wise)

[yiangosliv]

I have been using Honeywell Evohome for the 3rd year now and it works like a charm. Although, I am trying to minimize my WiFi devises at home (most of my networking is cabled at home), and I was wondering how safe/healthy HR92's are. My main problem is that one of the HR92's is about 1-1.5 meters away from my 3 year old son, so I was wondering whether I should do something about it. In the technical manual of HR92 it states : "Radio communication SRD (868.0 ... 870.0 MHz)
RX Class 2 -R ange: typically 30 m within residential buildings". I tried to contact Honeywell directly about this and the reply i got was an email reply:


"When the evoohme system is not used for a longer period of time ( during summer/vacation) there is no need to make any changes other than changing the temperature/schedule accordingly (turning the heating off, lowering the temperature, etc). If you take the batteries out or uninstall the HR92 it will lead to a lost of communication between the evohoem controller and the device and the binding might need to be redone once the system is to be used again. With the heating turned off, the controller would only communicate from time to time with the rest of the devices in the system to make sure they are still connected, and after some time it would go into a standby mode so the level of radiation would automatically decrease. We do not recommend turning the controller off or any of the other devices since that you reset the whole configuration of the system and you would not have any control over the hot water."

Then I asked "do you happen to have any official indication of the radiation levels the HR92/BDR91/Evohome Touch controller emit in winter (when fully functional) and while the system is on standby (during summer)"
and received the the below response:

" The radio frequency (not radiation) regulations are in the data sheet of each device (I attached the one for the HR92).The current regulation are the RED 2014/53/EU This is a Receiver Category 2 ISM(686.0-870.0MHz) Devices that work in this frequency band must not transmit more than 1% of the time."

I am also attaching an extract of the sheet Honeywell provided.

My question is whether HR 92 might impose any health risks (radiation) provided that its powered with 2 AA batteries? Anyone in this forum that could enlighten us in this subject?

[DBMandrake]

My question is whether HR 92 might impose any health risks (radiation) provided that its powered with 2 AA batteries? Anyone in this forum that could enlighten us in this subject?

All the Evohome components transmit at 868.3Mhz using only 10mW of power. This is a tiny amount of power compared to other devices such as Wifi Routers and Wifi clients or 3G/4G transceivers in mobile phones. To give some perspective Wifi power limits in the UK are:

Channel 1-13 - 100mW
Channel 36-64 - 200mW
Channel 100-140 - 1000mW
Channel 155-172 - 4000mW.

Of those the first three are the channels commonly used. So Wifi typically operates at power levels anywhere from 10x to 100x that of an HR92, and at much higher frequencies.

3G/4G transmit power limits in mobile phones are typically on the order of 200mW or 20x more than an HR92, and those transmit constantly for extended periods of time while held against your head...

As Honeywell state, their devices only transmit less than 1% of the time - so in every minute a given device is allowed to transmit for no more than 0.6 seconds. This is part of the regulations for the particular unlicensed ISM frequencies that are used to minimise interference with other devices sharing the same ISM band. In contrast Wifi routers and clients are very "chatty" and are constantly sending beacons and other control frames at a rate of many per second even if you're not actively downloading something. Likewise a phone during a call is transmitting constantly.

An HR92 will typically only transmit once or twice for a fraction of a second each in every 4 minute period.

In short, it's absolutely safe.

For what it's worth, I have an HR92 and a DTS92 both about 1.5 metres from my 2 1/2 year old son's bed and don't have any concerns whatsoever. (Apart from him fiddling with them and breaking with them! )

[jvallis]

Here's another story - a friend of mine, having come back from hospital with his newborn gently put him into his new cot in the next door bedroom to his for his first snooze. He noticed the temperature was a bit low and put the heating on. After an hour, the house was warm but the baby's room was not. In a rushed emergency he realised that while the radiator was lukewarm, it was totally not heating up the room while the rest of the house was quite warm.

Cue excuse to allow wife to accept immediate payment for evohome.

Moral of the story: evohome's benefit in giving your son a level, temperate environment to sleep well in far outweighs any radiation risk.

[DBMandrake]

Moral of the story: evohome's benefit in giving your son a level, temperate environment to sleep well in far outweighs any radiation risk.

Completely agree.

A comfortable even temperature in our 2 1/2 year old sons bedroom is a major benefit - the room is not terribly well insulated so would be far too cold in the winter without at least some heating. He tends to kick his covers off so anything less than about 16 degrees he'll wake up if he's ended up out of the covers and over about 20 degrees he can get a bit stuffy and dehydrated if he is still under the covers, so after a bit of trial and error I've found 18 degrees is ideal for him and lets him sleep comfortably right through the night virtually every night, and you can't put a price on that with a small child.

I even went to the trouble of fitting a wall mounted DTS92 about a metre above the cot (out of reach ) to more accurately sense the temperature by the cot, which is along a colder outside wall, this allows the temperature to be very closely regulated in the sleeping area regardless of whether the door/window are completely closed or ajar, which tends to confuse the HR92 as a temperature sensor. (Especially if the window above it is open, as it tries to compensate for the cold air coming in by overheating the room, but the remote DTS92 away from the window and floor is not fooled by this)

The room is scheduled to be 18 degrees from 7pm to 7am approximately and it gives me great peace of mind that regardless of how severe the weather gets the room will be automatically preheated to 18C by bedtime and never drop below about 17C at night. (It typically stays between 17.5 and 18.5) I use the same schedule year round and in summer the room naturally doesn't drop below 18C at night so the radiator automatically doesn't come on or call for heat. In spring/autumn it doesn't come on until maybe 3-4am when the temperature is starting to dip a bit in the night, and in winter it runs at a low heat through most of the night, all automatically. And no hallway radiator needs to be on at night for any of this to work.

I don't know if it's the same with other toddlers but a comfortable stable temperature seems to be a major factor for getting a good nights sleep - for everyone!

[yiangosliv]

Thank you all for the contribution on answering my question. I believe now I am much more relaxed about it