Combi boiler for 2/3 bathrooms, 5 bed house

[Bawbles]

We’ve just extended and added bedrooms and a downstairs shower room to an old Victorian detached house

The current (combi) boiler is in the family bathroom, is eight years old and been having issues for a couple of years but always fixable/ relatively low cost

When the plumber came yesterday he mentioned that as we will now have three bathrooms (inc ensuite) plus five beds he would recommend a higher spec when we do replace it

DH is keen to replace it as it’s been having regular minor issues and he wants to relocate it into the downstairs coat closet with the underfloor heating manifold and get all the works done while we are already renovating so he can bury pipes in walls etc

Would anyone recommend a combi for 5 bed/3 bath house?

Currently the ensuite has shower that runs off central heating but we are moving the ensuite so when we replace the fittings could put an electric shower in there

I doubt that even the most powerful combi could manage in the depth of winter with people trying to have baths.

I've never been impressed with ours (a Ferrolli) and it's constant niggly things and their poor lack of after service, but, in terms of if a combi can provide water / heating for that size of house, ours does the job.
We have 6 bedrooms and 2 bathrooms (+ 2 other separate toilets). Although it is more the number of people using them that would make a difference, not the number you have in your house.
If I use our shower at 6.30, then dh uses our shower at 6.45, it doesn't really matter to the boiler if that is one shower unit or two.
What makes a difference is if the boiler is heating enough for 2 people living in a house, or 8 people living in a house, I'd have thought.
We have 12 radiators, if that helps your calculations. 2 electric showers and one bath.

People wise there is only 4 of us - 2 adults, 1 teenager, 1 baby
8 rads upstairs, 3 downstairs plus underfloor.
*backforgood’ does your electric shower use the boiler to heat the water? Dh wants one as then if boiler breaks we have hot water. I assumed they all work independently of boiler but don’t know much about them

We have a combi for a four bed/2 bath plus toilet and underfloor heating. It's huge and it still couldn't keep the kitchen where the underfloor heating is over 18 during the last cold snap. Hit water was no problem. But our kitchen isn't particularly well insulated and is a Victorian property as well. The rest of the year it's fine.

We've got. A 5 bed house with 2 bathrooms and a downstairs loo witha. Combi and it great.

It's a Worcester Bosch and I think it's the biggest combi they do. House was toasty even recently.

Is it this floor standing one blankscreen? We are considering it as meant to hear 2 showers simultaneously

www.plumbnation.co.uk/site/worcester-greenstar-highflow-550cdi-combination-boiler-natural-gas-erp/?gclid=EAIaIQobChMI7p2ckJnc2QIVz7XtCh0BcwrQEAQYASABEgKTdPD_BwE

Electric showers do heat water if boiler breaks btw bawbles

If you’ve got electric showers, then you need the boiler for heating the house mostly so that should be ok.

To make sure it’s powerful enough, use an online calculator to work out the required kW’s. And I wouldn’t trust the installer to do it as in my experience they often don’t give it any thought and suggest boilers that aren’t suitable.

The house is going to be pretty well insulated as we are insulating the old walls internally and the extension wraps around two whole sides plus new roof etc.

It sounds like it would be sensible to make the ensuite shower an electric then it's less stress on boiler as the downstairs shower will be running off the boiler.

Why are electric showers all so ugly?

The plumber has recommended a Vailliant 938 boiler which is a combi but also has a built in hot water tank. He said this is designed for houses with higher hot water requirements. If I knew it could def cope with our house I'd rather have a 'proper' shower in ensuite as they look nicer.

Our combi diverts the hot water to the showers when in use. It works well. There's six of us using two showers, one bath, and a downstairs W/C. You shouldn't need an electric shower.

Sorry Bawbles - just got in. Yes, our showers work when the boiler doesn't, and they don't start running cold or going scalding hot when someone flushes the toilet elsewhere in the house like childhood showers did.

We have 5 beds 3 baths & a Worcester Bosch combi - works really really well.

We also have 5beds and 3 baths and a Worcester Bosch- it's great and the house it toasty warm

Don’t get electric showers - they are always rubbish! And if you have a new boiler it will be a very rare occurance that you need a secondary hot water source.

Have you thought about a mega flow or similar so you can run showers at the same time?

Is a mega flow a tank? That you have in addition to the boiler?

It’s an unvented tank + boiler.

www.theecoexperts.co.uk/megaflow-boilers

Thanks Fluffy, I've just had a google. I'm trying to avoid tanks as our loft has a very low pitch so isn't suitable for tanks.

We could put one in the airing cupboard in the family bathroom when we move the new boiler but it would mean losing all the linen storage which I use (the current combi is wall mounted above storage drawers.

I guess if we need one we will have to make room but hoping to do without. DH is adamant we need at least one electric shower which i see the practicality of (during boiler outages etc) but I love a power shower

If you have a new boiler - how many times will you experience 'boiler outages'? Virtually never.

If DH is insisting you must get a crappy electric shower make sure its in the bathroom he is going to use and don't inflict it on the rest of the family ;-)

Thing being Fluffy it's like everything - in theory a new boiler shouldn't break, but there's always one, and when it is your house without heating or hot water for the week over Christmas, then it really is nice to have a hot shower. Also, people tend to fit a boiler for the duration, not repleace it every 2 or 3 years, so there will soon come a time when it isn't a new boiler.
Up to OP, obviously, but there have been several times when we've been extremely grateful for hot showers when we've had no heating for a couple of days.

You got always have an immersion heater for hot water in case boiler breaks down - that’s what we have. Just had s week without central heating but still had hot water.

If you’re looking to replace the existing boiler, then make sure it fits in the space. If I’m not mistaken, that Vailant 938 is a big, deep unit so likely to be good 30cm deeper than the existing one.

Fluffy this will be my third combi in 12 years. I think in that time I’ve had issues pretty much every year. Sometimes it’s been pressure related (keeps going for no reason, valves seizing up etc) but having hot water at this times would have helped. Time before last was morning of my friends wedding and I had to go to a neighbours house for a shower.

We are having a big shower downstairs as the ‘main’ one and the ensuite will be secondary/smaller so I could compromise with the ensuite being electric as we won’t use it as much.

Jojo we’ve got a good space earmarked for shower room/ coat closet, the studded walls aren’t in yet so it will fit but I just want it wall mounted at then back as then can have the underfloor heating manifold directly below it and it keeps it all out of the way/ doesn’t use extra floor space

if you have a hot water cylinder (when a pressurised one like a Megaflow, or a traditional one, you can heat it with an immersion heater on the rare occasions when the boiler is out of action. Some people say that combis go wrong more often than conventional boilers, because they have more inside them, and it is more catastrophic when they do.

An important test for you and your installer is to see what is the incoming water flow to your house. Fill a bucket at the kitchen cold tap, time it, calculate litres per minute. Repeat the test at you scullery and garden taps if you have them. A Victorian house was probably built with a half-inch lead pipe, which may by now be squashed, and incoming flow may be very poor. A combi can't deliver more water than your supply, and may take a long time to fill a bath. It is possible to lay a new pipe, and you might get a lead replacement subsidy or other help.

The answer to your original question is "no."

We were going to go for a high flow one but actually our supply isn’t amazing so we saved a lot of money on one with s smaller maximum flow rate. Very happy with out new Worcester Bosch 38 cdi.

pigletjohn thank you I’ll do the water test. We don’t have any water downstairs currently apart from an outside tap but we can use that.

Our plumber had already advised replacing the feed so we changed this to plastic when digging up for footings. The water board didn’t charge us for the new connection, we just laid the pipework to the street.

Have you experience of the combi with the built in hot water tank?

I’ll ask the plumber about a cylinder, he’s been pretty helpful so far.