Room-stat v. TRVs

[JohnD]

(bri160356 says the house thermostat conflicts with the TRVs).

He is mistaken.

As is the article he quotes.

 

[Costeta]

OK thanks,
I've checked with the supplier/ manufacturer of the LightwaveRF TRVs and they are adding the functionality of the TRV calling the boiler when the TRV opens or closes next year which should solve the problem.

 

[JohnD]

does the cost matter?

 

[Costeta]

Yes. Being able to schedule and set the temperature of each radiator individually will save me money in the long run. I estimate the pay back will be about 3 years. I can switch off radiators that are not needed at different times of the day rather than having all the radiators on at once all the time the heating is on. I work from home so the heating is on most of the day but I don't need to heat the bedrooms for example during the day.
Why do you ask? Have you got a thought?

 

[JohnD]

No, but I was thinking, if, for example the fancy controls cost £50 extra per room, it might take 10 years to break even.

 

[Costeta]

Thanks for your thoughts JohnD. I will double check my calcs before doing anything.

 

[Dan Robinson]

I was referring to the product rather than the concept.

But Mr D is right, the payback time is significant. Spending money on insulation is more important.

 

[Costeta]

Thanks. I have a well insulated home. I rechecked my calcs and the pay back is 3.3 years.

 

[JohnD]

what do the controls comprise, and what will they cost, per room?

 

[Costeta]

The total cost is £420.
A single LightwaveRF Link at £60.
8No LightwaveRF TRVs at £45 each
I based my calculation on 8 months heating a year. My heating bill is £400 a year. I calculated on floor area of rooms in total compared to floor area heated when some radiators switched off and the revised time schedule.

 

[Dan Robinson]

Floor area is only part of the equation.

If you are trying to get a figure, you'll need to base it on heat loss calculations. Then as a proportion of the bill.

Even then I doubt you'll get the figures to match reality.

 

[bri160356]

Can I ask you to also look at this post
//www.diynot.com/diy/threads/lightwaverf-trvs.420531/#3265468[/QUOTE]

Already seen it. . Those controls look like shyte.

Hi Dan,

I wasn’t aware of Lightwave RF TRVs before I saw your post and although you say they “look shyte” I’d be interested to know why you dismiss them out of hand,....... or do you have experience of these units?

I havn’t seen any online reviews of the units........ either good or bad!

The idea of controlling TRVs through wireless technology sounds like an excellent idea to me; ....but as with any new technology sometimes the kit doesn’t always live up to the hype!
.....however, often it will.

Technology moves on, does it not?

 

[Dan Robinson]

It does.

Honeywell Evohome.


I am well versed


Just priced a 24 rad system with a bit of ufh and Internet control complete with 5 rads using 3 remote sensors due to daft radiator boxes.

 

[Costeta]

Living room - 14.4m2
Dinning room - 10.36m2
Hall - 10.4m2
Kitchen - 10.15m2
Landing - 7m2
Bathroom - 3.24m2
Bed 1 - 11.1m2
Bed 2 - 8.37m2
Bed 3 - 6.07m2
Bed 4 - unheated

Heating period Oct - May inclusive

Heating schedule pre LightwaveRF TVRs
On (all radiators) 6.30am Off 11.00pm

Heating schedule post LightwaveRF TVRs
Bedroom 1, 2 & , Living room, bathroom, kitchen, hall and landing on 6.30am to 8.30am
Living room on (all other rads off) 8.30am to 3.30pm
Living room, dinning room, hall, kitchen, (all other rads off) on 3.30pm to 7.30pm.
Living room, (All other rads off) 7.30pm to 10.00pm.
Bedroom 1,2 &3, Living room, hall, landing, bathroom on (all other rads off) 10.00pm to 11.00pm.
We go to bed at 11pm ish

 

[Costeta]

It works out at 3.3 yrs payback which I think is pretty good