Tado and Worchester Bosch.
Hi,
I have been trying to figure out why my bills are so high and have been trying to follow advice from the likes of Heat geek (which all makes a lot of sense) to lower the flow temperature and increasing the surface area of the radiators to try and reduce my costly bills. When i do this though, it ends up costing me more as the boiler is on more. I have a Worchester Boiler 8000 Life along with a Tado thermostat with TRVs, which whilst looking into it is possibly controlling via a on/off relay and not modulating. My bills are a fortune (£15-20 per day) and i am trying to keep my temps in the house as low as possible at 18 for used rooms and 15 unused rooms. It this due to my boiler not modulating? How do i correct this please?
Any help would be much appreciated,
Many thanks
Emily
Answers
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Hi, I can appreciate it as my consumption for a 3 bed flat is around 100kWh per day( as of 18 Jan 24, UK)
I suspect there's nothing wrong with your boiler or tado, as in my case, this is solely due to a very poor insulation. I too at the start followed the "low-and-slow" mantra, but that meant the temps would never reach the desired settings, unless the flow temp was around 70C, which led to me basically heating the outdoors with my money.
What I found is my living room has a heat loss of 13kWh on its own, so the only way to keep the flat warm and bills low is to seal off the living room when not in use. Here's where TRVs can help as I use them in that room only to microzone - only allowing that room to get warm from 6pm when it is in use. I still keep the flow to 57-60C to make sure the boiler is condensating, and it seem to do the trick, but it is far from being comfortable. My current consumption is 87Kwh, temp set to 19C. We used to have 23C in our old property with 6-9KWh heat loss for the entire 2 bed.
Persimmon Homes built my development in 2000 and it really is shocking how little has been paid to properly insulating flats.
If it is your property and it's a freehold or share of one, invest in insulation!
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Thank you for your response! I dont feel this is my issue, i can turn down my flow temperature to as low as 45deg and the house maintains temperature ok (its -2). But i still find my bills are more…because the boiler is on longer. For condensing boilers, i read everywhere that the lower flow temperaure the less gas and more efficiency for the boiler. (Which does make sense but not in my case) i think it’s because tado is on/off at 100% rather than modulating0
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Sure, although don't think modulation is the answer here.
So bills = kWh of energy or m3 of gas used and you set what % tado is at by adjusting the flow temp. If it is on/off and flow is at 45C( assuming the property feels comfortable) the usage will be X kWh per day. If it is modulating, the flow temperature will fluctuate, but the boiler will remain on as needed, and the usage will be Y kWh per day.
The difference between X and Y is not down to on/off vs modulation but how much energy you need to put into the property to keep it at a comfortable( desired) temperature and how well the property is able to keep that energy. In other words if you keep boiler on for 2 hours a day at 70C vs 7 hours a day at 45C, what matters is kWh in vs kWh out. Since you are well insulated, it could be your property requires a lot of kWh to keep warm and this is just that, no matter if tado is in relay or modulating. How big is your property, out of curiosity?
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Yeah I see what you are saying, that makes sense, but also doesn’t make sense that it costs me more to reduce the flow temperature? Everywhere I read states that it should reduce the amount of gas being used. I have a feeling my boiler is oversized for my home, hence the idea of modulating control. I am a large 5 bed house, with a 50kw boiler. This was chosen due to the amount of baths/showers and radiators I have. But quite a lot are not in use. Therefore it feels I am firing up the boiler every time to only heat several radiators, and then potentially my return temp isn’t low enough to have maximum condensing. If I open all my radiators more like heat-geek says, to increase my radiator surface area and decrease the return flow temp, it costs me more again. Something isn’t right that his theories which make sense, doesn’t work for me at all0
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One thing I can relate to is how utterly obsessed I became since getting tado with heating systems, heat loss calculations, boilers, flow and return temps etc etc.!
Circumstances are different, with heat geeks' advise working well for some properties and some systems and not others.
It would be best to look at the set up you have as you can only improve what you can measure. If you have smart meter, playing around with flow temp, checking consumption and how quickly set temp is reached can provide an insight into the best possible combination of flow temp/how long to keep boiler on. I have a system boiler so need to heat up water, hence being unable to keep low flow temp all the time.
It would cost less when your boiler is not on. As long as it is on, gas is consumed, at a lower rate with low flow/return temp, but still.
£15-20 per day assuming you are on around 22p per kWh, is around 200-250kWh ( minus VAT or standing charge) bit to much for a 5 bed, I would again advise looking into insulation,, as this will allow for the boiler to be off for longer.
It could also cost you more because your boiler is on for longer as it takes longer to get to the set temperature with low flow temp.
You can try and see if you can range rate your boiler down from 50kw, which also could offer some marginal gains.
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I also have a Worcester Greenstar boiler nearly new but not quite so large as yours and relay driven by a Wireless Receiver. Nearly every radiator in the house has a tadoº TRV and those with conventional TRVs (in areas of the house where tadoº RF reception is poor) are normally set very low or off.
My strategy with the tadoº TRVs is to heat only the rooms we are using together with background heat in the hall and landing. Thus in the morning only the hall landing and kitchen call for heat and at the end of the afternoon the sitting room is added to this. For the majority of the day the heating is off unless a room we are using gets very cold. This seems to work pretty well but there is one proviso, which some seem unable to observe, and it's pretty obvious; you must keep the doors between rooms shut!
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Thank you for your kind responses! yes, it has been a mega trial and error over the past year!
I have been operating it like that as well, but i feel like the house is really quite cold. i have been trying to reduce all room temperatures in use to 17.5 - 18 and then 15 when not in use (such as bedrooms) We have three floors - the bottom floor in not in much use therefore the heating is on very low/frost. I think this is causing cold air to migrate up through the floors as they dont have any insulation between them.
I work from home and have a young child at home all the time as well, therefore i need to heat half of the house all day long (kitchen, living room, office, hallway and playroom). Tonight i have tried changing half the smart trv's to 'dumb' mode and not calling for heat and then the main ones allocated to the controller. I am hoping this reduces the amount of time the boiler is on and will therefore cost less. albeit i have noticed already in the last couple of hours i have had to increase the boiler flow temperature as the rooms are struggling to meet (strange as its the ones that i still have linked to the controller!) anyways, will see how that goes and hopefully the smart TRVs will open more when the boiler is on.
Looks like the aim for me is to definitely reduce the amount of time the boiler is on!
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Personally I'd try and experiment with turning various valves off where you don't need them, the hallway will be drain on the boiler as it goes rapidly from hot to cold, especially if the front door is open. I don't have any type of smart valve on my hallway radiator at all, as it is the pass through one, thus it is only heated when the heating is on.
Close all doors and really you should control the heating for the room you occupy the most, not rooms you might occasionally use.
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Our strategy matches hugbilly. We micro-manage most rooms, a couple of dumb trv, use geo-fencing a lot and track everything daily The annualised pre-Tado kWh energy use for CH and HW was about the NEED mean kWh (UK energy-use data) for the size of house and Local Authority. The annualised kWh is now running at around 50% of pre-Tado.
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Have a look and see if your boiler CH output has been modified. Mine is a Vaillant and while the boiler is 35kw, the heating max output is reduced to 18kw. The boiler does modulate correctly as well.
It's a 1920's detached and we have a similar temp strategy, but over the last week we've use £9 a day instead of the normal £6 in winter. It's hard to make realistic comparisons when the outside temp is different. I'm with @wateroakley , Tado has reduced my usage by a significant amount.
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Found in what should be your installer manual. If the boiler is not range rated, the maximum gas goes up a lot.
https://www.worcester-bosch.co.uk/support/literature/download/release/6720883865/45590
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@mindstorm This is the comparison of our daily energy consumption (kWh) at the same outside temperature (mean CET), using data from January 2018 to October 2023.
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@mindstorm thank you for sending through that table! As per the table you sent, my % output is 70% on the boiler. Do you think reducing this to say 60% is worth a try? I appreciate you sending that though and helping me!0
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I'd take it down to 40% and see how it is. Work upwards in 4% units if thats not enough. I have 14 radiators in total and have mine set at close to 18kw/35% and it's fine in an older house. Boiler runs at a low temperature for longer but is saving gas. Sometimes the heating temperature is only 35deg.
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Ok brilliant thank you, I will try 40% first! if it’s too low will I find the house doesn’t cope to heat?0
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Probably it will be ok but if not, raise it 4% at a time until it's ok.
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