lowering DHW cost on a combi (Also known as eco shower heads)

[monkeysballs]

so im my continuing quest of dicking around to get my gas costs as low as possible (for fun more than anything)
i started looking at DHW production with my Viessmann 200 30kw combi
it was already alot lower than with my old vaillant in 2020 my average dhw usage about 250KWH 2021 about 180kwh (i turned down dhw temp) 2022 about 150kwh turned it down further and stopped using warm water for hand washing and this year after the new boiler 111KWh

but i thought damn it thats not low enough i mean ive gone from about 8kwh per day to 3.5! what can i do my dhw temp is set at 48c now

i had been looking why the boiler modulation was so high when having showers was between 60and 90% and well thats really quite alot it suddenly dawned on me its that high because its heating that amount of water! i decided to look at what my shower was using about 12-14lpm was just using a measuring jug and my phone couldnt find my wear cup

anyway i think haha lets reduce that so i put some neoperla flow regulators and pop them in and our modulation rates have dropped to 20-30% and comparing the recent showers we seem to be saving about 1kwh a day!

issue is now with a 6 litre fegulator in the wife is taking longer to shower as its not shifting the shampoo as the shower head isnt designed to run at low flow rates


so can anyone recommend a good low flow 6litre max over head shower head?
methven seem to do 2 the kiri satinjet mk1 and mk2 and hansgrohe Crometta 85 Green and Vernis Blend Overhead shower 200 1jet Green


but are there any others?

 

[polesapart]

Another approach would be to limit the frequency and duration of showers..

Surely a couple of minutes once or twice a week would be enough for personal hygeine?

Vide Queen Elizabeth 1's alleged bath regime.

 

[monkeysballs]

well no

i bough the hansgrohe head in the end. I tried it this morning and i like it but the mrs hasnt tried it and her hair is the issue

it feels higher pressure and it makes less mess as the spray pattern is smaller 200mm instead of 300mm head and it doesnt drip when shut off

i feel sore paying £80 for a plastic shower head though when the solid brass one is now sat there doing nothing

 

[flameport]

i feel sore paying £80 for a plastic shower head

How much gas would £80 buy?

 

[monkeysballs]

1142kw
Or maybe less than a year to pay off

 

[kidgreen61]

Why not go the whole hog, and fit a timer to the shower so that it shuts off after 3 mins?

 

[cdbe]

Read some smartarse the other day trying to show off about saving money in the shower - shower on -wet, shower off - soap, shower on - rinse, repeat for hair and other body parts. Meanwhile down in the kitchen the poor combi's having a fit!

 

[monkeysballs]

im tempted

but seems like its been accepted and gas usage is down, 2 showers 10:30 time for them both and consumed 1.98kWh similar earlier in the week was 3kWh and 4.64kWh for a similar day in june

 

[monkeysballs]

im encouraging the mrs to turn it of when she doesnt need it for a while like letting things marinade like hair stuff today there was a 4 minute gap between her turning it off and going back to finish off

i mean we arnt talking huge financial benefits and cost isnt the driver for this, its just me inner geek trying to understand an maximize what i can, whats the point in spending money on a great boiler if you dont try to make it work hard to maximize the benefit

and so far after the first 7 days we have used 22kWh so say 88 for the month and even over last month when i was already making improvements thats down from 112kWh (last 2 months have been the same usage) thats 24kWh saving pr £1.68 a month thats down from an average of 148kWh the year before and 176 the year before that looking at my bills.

lets see after next week and the cooler temps how the usage looks

but so far promising (and this shower head will work down to about 3.6l/m )

 

[Johntheo5]

Read some smartarse the other day trying to show off about saving money in the shower - shower on -wet, shower off - soap, shower on - rinse, repeat for hair and other body parts. Meanwhile down in the kitchen the poor combi's having a fit!

Is that the same person who switches off the windscreen wipers when driving under a bridge?

 

[monkeysballs]

so few more days in and it looks like a 28% reduction even including extra showers due to the weather being so bloody hot, my monthly average for last 2 months was 3.6kWh

 

[monkeysballs]

So confirmed

Replace shower head and save 34% on your DHW production (savings not guaranteed )
So after a month I have spent 73kWh on gas after replacing the shower head. Savings are likely greater as there were 3 or 4 baths taken this month usually only 1 and a few extra showers at the start of the month due to the heat

So yeah previous 2 months 111 and 113kWh

Is it worth the spend on the shower err no I'm saving £28.56 a year on gas on a £80 shower head so 33 months and gas prices are coming down slightly so maybe 3.5 years payback

But if you put a 6lpm flow restrictor in then at maybe £2 your golden if your shower head can cope with the low flow

I may try a 4lpm one in this and see if the Mrs notices

 

[roguetrader]

You sound a real bundle of fun!
Are you the guy that disappears before buying a round??

If it makes you happy, I'm well pleased for you.

 

[monkeysballs]

Hey the info could actually help people who are struggling with fuel costs it would benefit anyone not just combi owners

But you have got to admit it's a big saving on already low usage previous years it was up at nearly 300kWh so reducing temp of the water and amount of water being used I've got a reduction of about 77%