Deleted User 298457
Deleted User 298457
If I am binning my Hive TRVs - is it worth upgrading to an OpenTherm stat?
Gas Boiler Recommendations?
- Thread starter IC3
- Start date
Yes
The Drayton wiser is a good system it's come on leaps and bounds since it's release if you still want individual trv's
Evohome is better in terms of it's opentherm protocol and operations, but it's not user friendly to setup, once it is setup it's best to never touch it as its very difficult to get back to how it was. Honeywell have also made it obscenely expensive now which has made many people walk away from it.
Well my WC sensor has paid for itself far more than any Evohome or other 3rd party system will and will continue to increase my savings year on year vs other systems.
How is it better when it'll promote the boiler to cycle frequently?
All these thermostats and dedicated samrt TRVs will just constantly request the boiler fires, it's just a case of "OMG I NEEDS SMART APP EVERYTHING!
Do some calcs for your house, setup the system correctly, balance your rads, get WC installed and the whole thing will just work and in the most efficient way possible to maximise the time your boiler spends in the upper condensing zone. Or just spend all your money on 3rd party controls and control every rad so you "presume" it's the bestest way, when it really isn't. Less is more.
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It's actually better to keep the boiler on as much as possible rather than cycling.
During winter my boiler will be on for hours and hours without ever turning off. It just uses a flow temperature of saround 25c to keep the house warm or which ever rooms I choose. It does the opposite and promotes less or zero cycling.
I can't say I've ever used an App for my heating so not sure what that reply is about.
I did all calculations thanks, not that I really needed to but I put huge radiators in to suit a modern low flow temp system, no point balancing with Evohome.
Evohome leverages weather data as well to decide wether or not to even put the heating on that day.
Say the day time temperature is 20c bit it's a cold morning it'll leave it off knowing the rooms will warm up naturally, you can manually set the offset for this.
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Associate
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Is there any cheap(er) way of getting all rooms smart controlled? A whole house worth of smart TRVs is quite a sting!
Yes, using a weather compensation sensor with the first party controls will get you 99% of the way there without all the cost.
The whole point of using a weather compensation sensor is that it only puts enough heat into your hose to compensate for how much heat it loses for a given outside temperature. You can adjust the curve based (boiler flow temp vs outside temp) on the controls to hone it in for your specific house.
If your radiators are in the right ball park for each room, you don't even need TRV's and if you have any, you'll want to run them all almost fully open (or setting 4 of 5) to stop them shutting off unnecessarily. I run mine fully open all the time on my heat pump setup (the source of the heat is irrelevant).
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I think your confusing smart controls with boiler controls.
He asked specifically about room by room control.
There's a few different ones, Evohome definitely on the more expensive side.
British gas have Hive, theres Tado, Drayton Wiser, TP-Link Kasa. One called Salus appears to be pretty cheap.
I’m not confused.
You don’t need room by room control when using weather compensation, that’s the whole point.
You’ll spend more on ‘smart’ gadgets than you’ll ever have scope to recover in spending every so slightly less on gas.
I can only see room by room adding much value is if you have a house far larger than you actually need and you genuinely don’t use rooms for extended periods of time and you keep the doors shut and you have well insulated floors and walls between rooms. That just isn’t the reality for the vast majority of households.
What's the whole point, the two aren't separate things.
How does weather compensation only heat one or two rooms?
I went from Evohome as a whole house system to adding the smart valves and noticed a huge difference.
It's a comfort thing as well, each room is treated individually rather than the whole house as a single entity.
You keep saying weather compensation is better than smart systems but keep ignoring the fact that system use weather compensation along with load compensation.
So if weather compensation is best by your own words a system that then adds loads compensation as well can't be worse.
I said weather compensation is what gets you the vast majorly of the savings and benefits. The implied part of that statement is that you don’t need to spend close to the equivalent of an entire years gas bill on a house of ‘smart’ TRVs to get that result.
Weather compensation is what creates the higher levels of comfort, not smart TRVs. That is because the temperature isn’t yo-yo between 20c and 22.5C if you set the target temperature to 21C, it will just be 21C.
Radiators in bedrooms should already be sized slightly smaller so they’ll heat to a slightly lower temperature when on weather compensation as per the comfort requirements that most people want.
Weather compensation is what creates the higher levels of comfort, not smart TRVs. That is because the temperature isn’t yo-yo between 20c and 22.5C if you set the target temperature to 21C, it will just be 21C.
Radiators in bedrooms should already be sized slightly smaller so they’ll heat to a slightly lower temperature when on weather compensation as per the comfort requirements that most people want.
Deleted User 298457
Deleted User 298457
If I have a 55 degree flow temp anyway, can weather comp offer me anything?
Nope you size radiators based on the delta T of the system you're designing and room attributes.
Yes, and you size bedroom radiators to a lower room temperature because hardly anyone wants to go to sleep in 21C given most people sleep under a duvet.
So given the flow temperature and the heat loss of the room is common, to achieve a lower room temperature you install smaller radiators than you otherwise would do for a 21C target elsewhere in the house. That is the implied version of what I said without getting into really boring detail which the person asking the question doesn't need to know unless they plan on replacing the existing radiator, given they bulked at a bunch of smart TRV's, they are not going to go to these sorts of lengths.
Just because I didn't set out all the detail, doesn't mean what I wrote was wrong.
Better comfort and lower running costs.
Comfort because are only putting as much heat into the house as the house is losing and stopping that temperature yo-yo between the thermostat overshoot and when it drops below its target temperature. The further away these two numbers are, the less comfortable it is (typically ~2C), the closer the two numbers, the more the boiler cycles which impacts efficiency.
Running costs will be lower because your boiler will be cycling less. When it is cold enough to need the heating on, it will not be anything like cold enough to need the full 55C flow temp that is needed when there is snow on the ground in the middle of the day for those 5 days a year down south.
Probably better efficiencies. I bought one for my boiler because it was £25 and I already graciously had a wire to the outside that a previous owner put in for something but cut off before I moved in.
In my system the 55C flow temp only occurs at -7 outside. Which for the UK in middle of england is rare. It then tracks down to flow temp of 42 when its 10c outside. I however have issues getting it lower because a) my rads are sized for higher deltas, b) my boiler is 18Kw and only modulates down to around 5.5 to 6kW c) Speedfit microbore so rip flow rates d) my house is 2000 built so relatively ok for insulation. On the worst day last winter we pushed just over 100kWh of gas used so even with my boiler on minimum its not possible to run it for hours straight (never mind for a typical winter day). It’ll do a 10-15 minute stint every hour or there abouts normally.
To get better running characteristics on the boiler and also nicer comfort I balanced my whole house so everywhere heats to 21c at the same time with all rads open. I have TRVs but they are all wide open all the time and I have the heating set to 21c 24/7. Last year this resulted in about 8500kWh used for heating across Oct-Apr.
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Deleted User 298457
Deleted User 298457
Nice - is fitting one of these myself doable? I have access to outside via eaves (hipped roof). Vaillant loft in the attic, recently fitted.
Yes but you need the valiant controls which also support it.
You might need to do a bit of research before buying anything but if you’ve already got the right controls it should be DIYable. I’d think swapping the controls is also DIYable but obviously more work and cost.
Deleted User 298457
Deleted User 298457
Ah that's a shame. I bet they are $lol cost.
If you don’t already have them that is. That said, valiant is meant to have by far the best WC controls.
EBay/FB market place may be your friend also.
Soldato
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Bosh 4000 series.
Deleted User 298457
Deleted User 298457
Interesting - wish I had known this before. I kept with the Hive system because I had invested in the TRVs (which worked well in an 1880s cottage where you need to make sure the coldest room was topped up without cooking the rest of the house).
I can see the VSmart system uses internet weather compensation. I wonder if that works well enough.... Will give the plumber a text and see if he can price up new controls for me.
Edit: Sounds like it is just 4 wires (2 power, 2 ebus) - might give an eBay jobbie a go... Internet weather comp must be better than no comp.
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