Six ensuites with elec showers & just 1 bath. Combi or n

[tony101m]

Combi or system gas boiler? Just bought a large victorian detached repossession and hope to dabble in B&B business. It has an aging gas boiler and two fairly large hot water cylinders, but they have removed 8 of the radiators before being evicted. With peak demand issues in the morning planning on 6 en-suites with electric showers and just one bath. While a previous experience with a combi in a small semi 15 years ago took an age to run a bath, I am not sure if they are any better now. However, with mostly showers it seems inefficient to have large amounts of pre-heated stored hot water. Leaning towards a larger Combi boiler or two, but will this be sufficient?

Insulation? Also, with four external solid walls, EPC is suggesting some really horrid heating costs: £8000+ a year! This is probably so bad because no C/H and most Rads removed at present, but apparently previous occupants gas bills were over £4k a year. Plan to maximize loft insulation, suspend insulation under the floor boards and knock through the base of a fire place in the middle of the building to open both sides (with RSJ) and have a multi-fuel stove to blast out heat in all directions in the evenings for peak times. However, I cannot insulate the exterior walls and the interior has some very ornate coving so would be a problem to put the recommended 60mm internal boards up. Can get away with a 1 inch board, or would this be little use? Also need to consider rads and heavy items would need longer screws to hang, and there would need to be susufficeientable behind the electrics to bring the facias forward an inch or so. Cannot find any advice on internal insulation on solid walls.

Stained Glass Sash Windows? Finally, the sash windows on three of the walls have stained glass at the top. While it is not listed it would seem criminal to replace these, but they are very poor for thermal and noise insulation and are rotting in places. Could the stained glass be incorporated into replacement wooden double glazed sashes at a reasonable cost? Alternatively, any ideas on sliding secondary units?

Suggestions, other than should have bought a modern house, appreciated.

 

[scoobydo123]

Before doing anything you need to know what the mains pressure and dynamic flow are. Even electric showers 6 on the go at once could be pushing it. Might need accumulator to ensure whatever solution can satisfy all at once. I had something much the same and designed part gravity and part un-vented, less demand on incoming mains and redundancy in the event of boiler issues ie backed up with immersions. In this config you may be able to get away without an accumulator.

Regarding insulation there are various blanket type that suppose to be super insulators not sure how good these are in practice. Majority of heat is lost upwards anyway. Dont worry about fixings as long as you plan everything out then just put studs where fixings required electrics should not be a problem either. But the cost of all this against your return if you were to insulate the interior walls may not give a good return but you are doing the right thing for the environment. Also dont forget that you will not have 100% occupancy all the time so not all rooms will need heating to the min required.

 

[Ian2008]

Also check your electic supply.
6 electric showers all running at once is a huge load, excluding any other electrical loads.
The property will probably need a supply upgrade and your DNO will need to be told about your proposed electrical needs.There may not be enough spare capacity in the network to cater for that.

 

[calorific]

If you are going to use the rooms for BB purposes, then (leaving the plumbing issues aside to others on here who can advise), is would be entirely feasable to install highly insulated floating ceilings below the ones currently in place. This would mean that you would be able to (in at least some of the rooms):

1/. preserve the cornicing until you win the lottery and can restore the house to it's former glory and afford to heat it

2/. improve sound (as well as heat) insulation between floors.

3/. enable you to insulate the external walls without losing the cornice.

4/. hide any new pipework required for washbasins in the rooms

5/. etc etc etc

 

[tony101m]

Before doing anything you need to know what the mains pressure and dynamic flow are. Even electric showers 6 on the go at once could be pushing it. Might need accumulator to ensure whatever solution can satisfy all at once. I had something much the same and designed part gravity and part un-vented, less demand on incoming mains and redundancy in the event of boiler issues ie backed up with immersions. In this config you may be able to get away without an accumulator.

Regarding insulation there are various blanket type that suppose to be super insulators not sure how good these are in practice. Majority of heat is lost upwards anyway. Dont worry about fixings as long as you plan everything out then just put studs where fixings required electrics should not be a problem either. But the cost of all this against your return if you were to insulate the interior walls may not give a good return but you are doing the right thing for the environment. Also dont forget that you will not have 100% occupancy all the time so not all rooms will need heating to the min required.

Thanks Scoobydo123. Will do a check on water pressure and realize I may need a large pressure storage vessel if going the electric shower route. Also reading up on the ACV tank-in-tank options that seem very efficient for a stored water system, if you believe their own website, but the principal seems to make perfect sense. Interesting they have no prices though.

 

[tony101m]

Also check your electic supply.
6 electric showers all running at once is a huge load, excluding any other electrical loads.
The property will probably need a supply upgrade and your DNO will need to be told about your proposed electrical needs.There may not be enough spare capacity in the network to cater for that.

Thanks Ian2008. DNO? I never thought it would be that significant. I was considering 10.5 KW electric showers as there would be no hot water running out and just heating at point of use. Realize I would need meaty cable and dedicated large circuit breakers / fuses. However, thanks for reminder to look at that.

 

[tony101m]

If you are going to use the rooms for BB purposes, then (leaving the plumbing issues aside to others on here who can advise), is would be entirely feasable to install highly insulated floating ceilings below the ones currently in place. This would mean that you would be able to (in at least some of the rooms):

1/. preserve the cornicing until you win the lottery and can restore the house to it's former glory and afford to heat it

2/. improve sound (as well as heat) insulation between floors.

3/. enable you to insulate the external walls without losing the cornice.

4/. hide any new pipework required for washbasins in the rooms

5/. etc etc etc

Thanks Calorific. Again, never thought of that, I'll look into it.

 

[RF Lighting]

Also check your electic supply.
6 electric showers all running at once is a huge load, excluding any other electrical loads.
The property will probably need a supply upgrade and your DNO will need to be told about your proposed electrical needs.There may not be enough spare capacity in the network to cater for that.

Thanks Ian2008. DNO? I never thought it would be that significant. I was considering 10.5 KW electric showers as there would be no hot water running out and just heating at point of use. Realize I would need meaty cable and dedicated large circuit breakers / fuses. However, thanks for reminder to look at that.

Your proposed load is THREE times the capacity of the standard UK domestic supply.

You might be lucky and have a 3 phase supply to the property, but is's still going to leave little capacity for any other load in the property such as your breakfast kitchen.

Either way it's going to require some heavy commercial electrical work to be carried out.

 

[dcawkwell]

Using electric showers would be a mistake.
Do you see a travelodge using electric showers?
You need to keep running costs down and that means gas for cheap
hot water.

As previously stated you need to measure the incoming flow rates
and analyse what demands you may need.

Unvented cylinder(s) and accumulator tank(s) most likely necessary.
Consider acv unvented cylinders very fast reheat times and will
drag as much as the boilers can supply reheating water.

Double glazing. No use getting sentimental.
Wouldn't worry about insulating above the normal.
Zone the rooms so that you can control heating to rooms not in use
and therefore save heating costs.

 

[Dan Robinson]

How about a buffer tank and plate heat ex hangers.

Rooms fitted with flow limiters and tmv valves. Heat the tank by any means necessary including a couple of small commercial boilers that can also feed a zoned and remotely controlled heating system.

Or alternatively use small AC units that can heat and cool the rooms as needed. If you are that anal you can fit energy meters to each one

 

[tony101m]

Using electric showers would be a mistake.
Do you see a travelodge using electric showers?
You need to keep running costs down and that means gas for cheap
hot water.

As previously stated you need to measure the incoming flow rates
and analyse what demands you may need.

Unvented cylinder(s) and accumulator tank(s) most likely necessary.
Consider acv unvented cylinders very fast reheat times and will
drag as much as the boilers can supply reheating water.

Double glazing. No use getting sentimental.
Wouldn't worry about insulating above the normal.
Zone the rooms so that you can control heating to rooms not in use
and therefore save heating costs.

Thanks DCawkwell. OK, so the message is clear to steer away from 6 electric showers, and whatever way I need to check flow rates and increase pressure as necessary. If I go for a system then, I like the idea of the tank-in-tank ACV cylinders: probably have two for the 5 showers and then perhaps have just 1 electric shower in our area for redundancy.

I was going to put Drayton TRV4s everywhere bar 1 rad, but would I still need to zone?

If I went for a very large combi, I saw a mahusive one that come out very well on the Which? tests, a Worcester Greenstar Highflow 550Cdi. It says it is very good for very large detached houses, or much older period properties with poor insulation; also has low minimum output for heating when needed but has a lot of extra power to heat up rads quickly (7.4 - 29.2kW and 89.2% efficient). However, while hot water heat output is a massive 44kW / 20 litres/min, the water efficiency is just 49% - not sure how expensive this would turn out to be for heating water. Is it worth considering this as a part-combi option?

 

[Dan Robinson]

You would be barking to use a Combi.

 

[tony101m]

How about a buffer tank and plate heat ex hangers.

Rooms fitted with flow limiters and tmv valves. Heat the tank by any means necessary including a couple of small commercial boilers that can also feed a zoned and remotely controlled heating system.

Or alternatively use small AC units that can heat and cool the rooms as needed. If you are that anal you can fit energy meters to each one

Thanks Dan. One way or the other I need to have capacity for peak use when full, but more than half the time have minimum need of much hot water so be able to minimize what is pre-heated. Are tmv valves the same as trvs?

 

[Dan Robinson]

Are tmv valves the same as trvs?

They limit the temperature of the hot water outlet.

A buffer tank can be heated in several ways.

You can have the controls set to only heat the top half in quiet periods, and the whole thing during peak demand.

 

[mickyg]

an electric shower is high on my list of gripes in any hotel, b&b whatever. dont do it.
Most important thing for hotels etc.. good pressure, and backup in the event of failure. There's so many ways you can go about this kind of job, its best to get someone in to survey. At the end of the day it will come down to costs. A bank of water heaters is a good way to go, but that can be expensive.