ash_scotland88 Posted April 8, 2021 Share Posted April 8, 2021 Doing some mental planning ahead and looking to hear advice on how to heat water for three showers - only one currently exists. If all three get built we would have the ensuite, upstairs bathroom and downstairs shower room. Bathroom and shower room need renovated. The upstairs bathroom is currently a bath, wc + sink and separate shower-room which will be knocked together, the ensuite will be the last on the list to be built and could be a number of years down the line. Boiler (combi) is being specced to supply two showers. If all three happen the downstairs shower room would be the least used, so does this make sense to run off more expensive electric? Or would the ensuite be best for electric as it preserves flowrates/water pressure for the possibility of someone also using the bathroom at the same time? Link to comment Share on other sites More sharing options...
ProDave Posted April 8, 2021 Share Posted April 8, 2021 I think the more important question is how many people in the house usually and how many showers are likely to be used at once or in quick succession. and what heating source you have at the moment / plan to have? Link to comment Share on other sites More sharing options...
ash_scotland88 Posted April 8, 2021 Author Share Posted April 8, 2021 Current heating source is immersion and electric shower, radiators are electric (not storage, not anything fancy just plane old gets hot metal radiators) All quotes are coming in for a combi. Currently just the the two of us but future proofing for family. Link to comment Share on other sites More sharing options...
joe90 Posted April 8, 2021 Share Posted April 8, 2021 5 minutes ago, ash_scotland88 said: All quotes are coming in for a combi. I presume you want/have main gas? Link to comment Share on other sites More sharing options...
ash_scotland88 Posted April 8, 2021 Author Share Posted April 8, 2021 1 minute ago, joe90 said: I presume you want/have main gas? Yes, and got an install date. House is too big and too old for anything like ASHP, sadly. Link to comment Share on other sites More sharing options...
TonyT Posted April 8, 2021 Share Posted April 8, 2021 Get a system boiler off the gas, with immersion back up. 1 Link to comment Share on other sites More sharing options...
ProDave Posted April 8, 2021 Share Posted April 8, 2021 System boiler with unvented hot water tank and thermostatic mixer showers. you will not be disappointed. Link to comment Share on other sites More sharing options...
PeterW Posted April 8, 2021 Share Posted April 8, 2021 53 minutes ago, ash_scotland88 said: All quotes are coming in for a combi Yes because the plumbers love them as it’s 4 pipes and a controller and they still get paid a grand to fit it. I’ve never seen a combi cope with two decent showers, and you need a lot of flow and pressure to cope with it anyway. System boiler, 25mm into the house, 22mm to the UVC and balanced cold then 15mm to the showers. Link to comment Share on other sites More sharing options...
ash_scotland88 Posted April 8, 2021 Author Share Posted April 8, 2021 None of the heating engineers recommended one as a solution, a couple raised in passing about storage combis. Grew up with a hot water tank, plenty of disappointment as the water ran out. Or coming home from somewhere in need of a shower (or a mid day baking session) and as it was used up in the morning had to wait for the water to heat. Even a thermostatic shower some-one running the kitchen tap and had to step out the shower due to the change before it adjusted itself- don't even think about filling up the kettle if dad was in the shower! I appreciate efficiency moves on in 20years. Even the future in-laws who had a replacement done a couple of years a go these issues still persist- but no idea on their system apart from it being a tank. I understand why you two are suggesting it, due to very little loss of flow. Boiler's we've been quoted have had 16+ Lpm flow rates. Which I know is determined by our mains feed but then a tank can also be. Then there is more work and space requirement for moving the immersion out of a bedroom cupboard and I am limited by the space the house has to offer. All this is just more day rates for the plumber so surely they would prefer this if it was all about money for them? Apart from the odd occasion possibly all three showers will be running at once and someone washing up it's not needed and doesn't answer the original question. But planning to future proof for 5-10years time when there will be two adults and a child (or two) showering before work and school. Link to comment Share on other sites More sharing options...
joe90 Posted April 8, 2021 Share Posted April 8, 2021 Just to add, make sure you size the tank big enough and very well insulated . Any heat that does escape from the tank heats the airing cupboard then the house so not a total loss. Link to comment Share on other sites More sharing options...
TonyT Posted April 8, 2021 Share Posted April 8, 2021 If you are talking about future proofing a system boiler does that with the hot water cylinder having an immersion back up, use PV to provide power for the immersion. If you have experience of lack of water with a gas based system, it’s not installed properly or you aren’t using it properly. combis for small flats, houses. I have a WB high flow 550, a combi the size of a washing machine, only because I can’t find the space for a cylinder- compromise due to Victorian property Link to comment Share on other sites More sharing options...
PeterW Posted April 8, 2021 Share Posted April 8, 2021 39 minutes ago, ash_scotland88 said: Boiler's we've been quoted have had 16+ Lpm flow rates. thats not enough for 2 showers .. Link to comment Share on other sites More sharing options...
A_L Posted April 8, 2021 Share Posted April 8, 2021 4 hours ago, ash_scotland88 said: Boiler (combi) is being specced to supply two showers. A 9l/m shower is about 22kW. How about fitting waste water heat recovery (WWHR). The en-suite and upstairs bathroom could be fed into a vertical system with 60% heat recovery and the downstairs 45% heat recovery. So about 9kW each for upstairs and 12kW for downstairs. So any two should be easily within reach of a 35kW boiler. https://recoupwwhrs.co.uk/ https://showersave.com/ Link to comment Share on other sites More sharing options...
Iceverge Posted April 8, 2021 Share Posted April 8, 2021 4 hours ago, joe90 said: Just to add, make sure you size the tank big enough and very well insulated . Any heat that does escape from the tank heats the airing cupboard then the house so not a total loss. good point. If you want to store a given amount of energy a larger tank will loose less heat per kWh stored than a small one. You could also add a second tank if space or floor loadings are an issue. I reckon our 300l cylinder @70deg does 4 x 15 minute showers with no reheat. System boiler, 300l min UVC Thermostatix mixer showers. Maybe allow wiring for a single electric shower if you need it for peace of mind. Link to comment Share on other sites More sharing options...
ash_scotland88 Posted April 18, 2021 Author Share Posted April 18, 2021 Thought I posted this on friday.. _____________________________________________ Sorry guys, spat out my dummy a wee bit. It's nice talking about fitting further heat recovery methods, PV panels etc, but any of you guys feel like gifting me the money to do so? The downstairs shower room would be only occasionally used and on rarity, the most day to day use it will receive is when the family bathroom gets modernised. Trying to research figures on flow rates of showers but very few give information on them, on a standard thermo mixing shower head anywhere between 3l/m-6l/m it appears, so allowing a further 10-13l/m for a fancier rain shower head for the odd occasion both are in use appear reasonable, or am I missing something here? @TonyT one company came back disucssing high flow rate boilers, but looking on paper apart from brand it's offering the same L/m and Kw as other boilers (worcester vs ideal) so what may the difference be*? Our house (big old 30s but limited on space where to put an immersion in a sensible location) current tank is only half height under the attic stairs in a bedroom. Any way decided in the short term downstairs and upstairs will run off combi, and if the 10year plan of an ensuite comes to fruition then boiler/how showers are heated can be re-evaluated then. Link to comment Share on other sites More sharing options...
TonyT Posted April 18, 2021 Share Posted April 18, 2021 Do you have a loft? stick boiler etc up there make sure area floored, safe to access and with light Link to comment Share on other sites More sharing options...
markocosic Posted April 19, 2021 Share Posted April 19, 2021 Unvented cylinder with a BIG coil for fast reheat (fit a heat pump cylinder) and a system boiler. That's then future proof if you do go the heat pump route. Or a big combi for two showers and the emergency shower an instantaneous electric affair for when the combi breaks down. ATAGs have economisers / passive flue gas heat recovery to REALLY condense in hot water mode to give 16L/min at a 35C rise, which once blended to shower temperature gives you two simultaneous showers at ~9.5L/minute or three at a usable if uninspiring flowrate if you must. Don't do rain showers with that though and watch your pressure drops. (the pressure drop through combis is high compared to a UVC) Depends what you mean by a shower really! https://www.atagheating.co.uk/homeowner/products/boilers/combination-boilers#specification Link to comment Share on other sites More sharing options...
ash_scotland88 Posted May 6, 2021 Author Share Posted May 6, 2021 So had an other visit today from an engineer/surveyor/installer and he's been the only one that's backed up what a lot of you said that a combi running two shower's wont give the "wow this is a good shower" response. But also agrees with us that one downstairs running off the combi downstairs which will hardly be used it will not matter. Link to comment Share on other sites More sharing options...
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