Combi and two showers best options without cylinder

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We have a house with two bathrooms. It has a combi boiler (WB Greenstar jr 24), everything is plumbed in and fitted already and we absolutely have nowhere to put a cylinder in the house. We lived in it as a family which was when it was all fitted, and as we never really used the two showers at the same time, it was never an issue, but it is going to be let and we need to ensure that the showers can be used at the same time. I know a cylinder is the best option but its also impossible in this house as there is just nowhere to put it, so I have to find another option and would welcome some advice.

The mains water pressure is about 10l per minute off the kitchen tap (right over the rising main).

These are the options as I see them:
1. one shower runs off the combi and we fit a powerful electric shower to the other. But do we have the water pressure to mean both would still work at the same time?
2. Use some kind of hot water heater to one of the bathrooms.
3. Replace the existing combi with a storage combi.
4. Another option (please don't say cylinder!! I know even though I've said that I'll get several answers saying 'fit a cylinder'. And in an ideal world that would be lovely, but in this scenario its just not possible, we've explored every possible option and just can't make even a small one fit).

In case anyone saw my previous post about this, we've had to change the plans for the house do to financial constraints, hence the second post with a slightly different request.
Thanks
 
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Your water flow rate is a bit low for 2 simultaneous showers and you really need to know what the static and dynamic pressures are.
Since you've already got everything installed, try running 2 showers at the same time and see what happens. Assuming you have thermostatic showers, experiment with the flow rate on both to see if there's any benefit from installing flow restrictors to one (usually the shortest pipe run).
Don't forget to test the outcome from switching kitchen hot tap on (and off) while both showers are running. If shower temperatures stay stable but flow decreases that's acceptable, if shower temps drop or increase noticeably then not really good enough.

EDIT Electric showers at best give acceptable performance. The thermostatic ones (rather than the cheapo flow regulated types) should reduce temperature drops/increases caused by changes in incoming pressure but it'll still be an average experience at best.
 
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Quite agree with oldbutnotdead. The only thing I'd add that if its going to be let, the electric shower option also has the advantage of providing a source of hot water if the boiler breaks down. Tenants with no hot water can, understandably, get quite irate.
 
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Thanks @oldbutnotdead and @oldbuffer. At the moment I can't go and check the water as our family are in covid quarantine, so I'm trying to get as much done as possible remotely. As far as I remember when you turn on one shower the pressure drops significantly on the other one. Can I just clarify then, do you think an electric shower is a good or bad idea and under what circumstances? I'm talking about a very good quality one - something like a Mira Sport. I like the idea of it acting as a backup in case the boiler breaks. My intention would be to put this on the main shower (the one that would be used by three bedrooms so would get the most intensive use) with the combi only providing water to the en-suite in the loft bedroom so getting less use, but I'm not sure if this is a good or bad idea. It would mean it getting a lot of use - but putting the electric shower in the loft would mean it wouldn't be a backup as only one room would have access to that bathroom.

If not an electric shower, what else? A water heater in one bathroom?

I've found a possible location for a cylinder, but it would have to be very small (the space is only the size of a washing machine) so I'm not sure if this is really big enough. Any idea? It would need to be connected to the combi that's already fitted as can't afford a whole new boiler as well at the moment but I gather this is possible. I'm assuming a cylinder can also be used with an immersion type heater if the boiler breaks down?
 
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We have a house with two bathrooms. It has a combi boiler (WB Greenstar jr 24), everything is plumbed in and fitted already and we absolutely have nowhere to put a cylinder in the house. We lived in it as a family which was when it was all fitted, and as we never really used the two showers at the same time, it was never an issue, but it is going to be let and we need to ensure that the showers can be used at the same time. I know a cylinder is the best option but its also impossible in this house as there is just nowhere to put it, so I have to find another option and would welcome some advice.

The mains water pressure is about 10l per minute off the kitchen tap (right over the rising main).

These are the options as I see them:
1. one shower runs off the combi and we fit a powerful electric shower to the other. But do we have the water pressure to mean both would still work at the same time?
2. Use some kind of hot water heater to one of the bathrooms.
3. Replace the existing combi with a storage combi.
4. Another option (please don't say cylinder!! I know even though I've said that I'll get several answers saying 'fit a cylinder'. And in an ideal world that would be lovely, but in this scenario its just not possible, we've explored every possible option and just can't make even a small one fit).

In case anyone saw my previous post about this, we've had to change the plans for the house do to financial constraints, hence the second post with a slightly different request.
Thanks
If you explain the current operation to potential tenants, they may not be too bothered about it so it might not be a show-stopper. If so you don't need to do anything.
 
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If you explain the current operation to potential tenants, they may not be too bothered about it so it might not be a show-stopper. If so you don't need to do anything.
The rooms are being let as separate tenancies as an HMO (so not to a group of friends, to separate individuals who don't know each other), so I don't think that's really an option. I need to find a way to make it work as I know it would put me off if I was looking for a room.
 
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The rooms are being let as separate tenancies as an HMO (so not to a group of friends, to separate individuals who don't know each other), so I don't think that's really an option. I need to find a way to make it work as I know it would put me off if I was looking for a room.
OK, see what you mean
 
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Hmm. Electric shower best avoided- they are at best adequate and cost significantly more to operate than the equivalent shower volume heated by gas (presumably bills are included since it's shared facilities so this will affect your operating costs).
Your water flow rate currently is probably too low for an unvented cylinder to work so you'd need a header tank for your small cylinder as well, you need the header as high above its shower as possible to give any sort of decent flow rate (3 metres minimum) or you need a flange and a pumped shower.
The pressure/flow drop from one when you operate the other will be a real irritant to the tenants.
If you have the time, get your water provider to check dynamic pressure and flow rate at the meter/street stop tap- given HMO setup it would be wise to explore how much improvement you could get in water flow/pressure by replacing the (probably lead or half inch iron) supply from stoptap to house.
Short term fix, I'd put the electric shower (thermostatically controlled) in the ensuite. Or use one of those undersink 10.5 kw flash heaters to supply a thermostatic shower bar in the ensuite- less to replace if you can sort the water supply out and find an unvented cylinder to go in the cupboard.
Long term improve the water supply then cylinder etc in the ensuite.
Kitchen hot tap is still going to cause problems (kitchen cold might as well til you improve the house supply)- you might want to look at restrictors in both to avoid pathetic shower performance.
 
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Hmm. Electric shower best avoided- they are at best adequate and cost significantly more to operate than the equivalent shower volume heated by gas (presumably bills are included since it's shared facilities so this will affect your operating costs).
Your water flow rate currently is probably too low for an unvented cylinder to work so you'd need a header tank for your small cylinder as well, you need the header as high above its shower as possible to give any sort of decent flow rate (3 metres minimum) or you need a flange and a pumped shower.
The pressure/flow drop from one when you operate the other will be a real irritant to the tenants.
If you have the time, get your water provider to check dynamic pressure and flow rate at the meter/street stop tap- given HMO setup it would be wise to explore how much improvement you could get in water flow/pressure by replacing the (probably lead or half inch iron) supply from stoptap to house.
Short term fix, I'd put the electric shower (thermostatically controlled) in the ensuite. Or use one of those undersink 10.5 kw flash heaters to supply a thermostatic shower bar in the ensuite- less to replace if you can sort the water supply out and find an unvented cylinder to go in the cupboard.
Long term improve the water supply then cylinder etc in the ensuite.
Kitchen hot tap is still going to cause problems (kitchen cold might as well til you improve the house supply)- you might want to look at restrictors in both to avoid pathetic shower performance.

Hmm, I'm pretty sure its blue plastic supply pipe actually so little to improve I think.
 
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Hmm, I'm pretty sure its blue plastic supply pipe actually so little to improve I think.
Really? That's a bit poor then, well worth getting onto your water provider to measure flow/pressure at the meter. 10 litres/min is poor (I'm getting 30l/min at 2.3 bar dynamic).
If their end is good, you can improve things internally with larger pipe and straight runs but that's not really feasible in a decorated finished house.
If you have space for a header tank, cylinder etc for the ensuite your tenants will have a significantly better experience (make the header big enough so it supplies cold as well to that shower).
If not or can't at the moment then stick the electric one up there (will involve a big fat cable), with the low flow rate they'll at least get a hot shower.
 
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