Combi boilers

Another plumbing dilemma!

We currently has the old fashioned style water system with a large hot water tank in the bathroom and cold water tank in the attic.

We are planning to redecorate the bathroom and it would be nice to rip out the old hot water tank before we decorate. If we do it after decorating, we're going to have a horrid hole where we have tiled the floor and walls

We are thinking about switching to a Combi boiler but are undecided. It's going to cost around £2500, so we are reluctant to do this when our old boiler is working perfectly well. We've also been told that the old system is more reliable.

But sometimes we are clearly wasting energy. For example in the mornings we have the hot water on for an hour, it heats the whole tank. But our shower is electric so heats it's own water. We only use a tiny bit of hot water for washing up breakfast bowls etc in the morning, heating a whole tank seems like a waste. Plus the old boiler will need replacing at some point. If we're going to do it, now seems like the time. But is it really necessary? Are Combi boilers better? Both systems seem to have pros and cons

Anyone had both systems? What do you prefer?

We had the old style boiler in our previous houses to this one and in this one was a combi boiler I didn't rate much but it was getting on in years.
We changed boilers about 3 years ago and I think you will find even combis are obsolete now it is condenser boilers they install if you are upgrading ours is wonderful hot water on tap (excuse the pun).

I used to have a conventional boiler and when it gave up the ghost replaced it with a condensing boiler but I opted to keep the tanks as I like and use my airing cupboard and the cold tank is in the loft out of the way so no point getting rid.
why do you have your boiler on for an hour in the morning if you use little hot water, change the timer. We use loads of hot water but only have the boiler on for half and hour morning and evening for hot water as the heating never goes on. I replaced mine a couple of years ago and was told then combi's were cr@p.

We changed to a combi from a conventional type in our last house. Loved it as it meant hot water on tap ('scuse the pun) and it was more cost effective.

Where I am now we are all electric as they don't have gas here and I so miss my gas heating and combi.

Had the combi in the previous house when we changed it from what you have, so got rid of all the tanks and pipes, gained so much space in the hallway knocking out the cupboard which housed it too, and I loved the hot water on tap and the power showers from it.

New house, another combi, although it's probably a condensor coz it's only a year old but still as good as our old combi was, instant hot water, and no waste of heating up a great big tank of it just for bits of hot water here and there. We don't have baths, only showers and the combi does what we want. Of course, it would also run a bath, but if we had what you've got, then it would fill the tank back up with cold water and cost you to heat it all again, it's a waste of money if you're not using it. Different with a house full of people and kids.

C/H was my trade since the 60s before I retired 5 years ago.

With the new law all boilers must be Condensing either Conv or Combi and at least 91% efficient that means for every £ spent you get 91p of usable energy, older type boilers tend to be around the high 70% to low 80%

With the Conv you also have to up grade your storage tank and water tank to meet the new regs.

Storage tank has to be foam lagged and not a Jacket, all pipes in Airing cupboard have to be lagged as well, Cold water storage tank has to meet the new water board regs as well.

On the whole modern Combis are just as reliable as Conv boilers.

my mum has always hated the combi boilers we have had

main gripe is having to fiddle with the bath tap to get the water to come out hot

i think it is something to do with having the wrong boiler for thehouse as since she had a new one installed it is apparently better than it was

i guess my coment would be to get the right one for your size of house

Until a couple of months ago I had an ancient back boiler behind a delightfully (not) retro gas fire in the living room. I had hot and cold water tanks in the bathroom cupboard so it sounds very similar to your set up.

For five years I put up with it "because it works"; my gas bills were HUGE because it was so shamefully inefficient, I put up with having no hot water at all whenever it was warm enough to have the heating off (no hot water for baths/washing up all summer, my shower is electric like yours), I had no thermostatic controls so it was either freezing or roasting and it was generally a pain in the rear.

I had the fire and boiler serviced this year and that is what pushed me to finally do something about it. Although both were within the legal limits, the plumber told me he thought within a year or two they would probably be condemned. I decided to bite the bullet and get it sorted before winter set in. I had a modern combi installed (Worcester Bosch 25si – I didn’t need anything hugely powerful as my house is small and hot water requirements are minimal). OH MY GOSH, it was the best thing I’ve ever done!

Good points:
1. I can now have instant hot water when I turn on the tap, whether the heating is on or not. I don’t have to plan hours in advance if I want a bath or to wash up, and I don’t waste energy by heating a massive tank every time.

2. Getting rid of the water tanks in the bathroom cupboard has cleared a load of space which is great for storage.

3. I’ve been able to get rid of the horrible old gas fire and replace with a pretty new stove (only electric as it’s mostly for show). This has also given me more space in the living room. The new stove also has a remote control which is practically a whippet remote control, as they gravitate towards heat! Sneaks being a pain while I’m sitting on the sofa > Use remote to switch fire on without getting up > Sneaks goes to lie by the fire > Use remote to switch fire off > Sneaks enjoys residual heat and can’t be bothered to move again

4. I can have the heating on without wasting a squillion pounds because a) the boiler is so much more efficient and b) I have a wireless thermostat to make sure the house doesn’t keep heating up over a certain temperature. I can move the thermostat into different rooms, e.g. take it to the bedroom at night, have it in the living room in the evenings or even leave it where the dogs sleep during the day in winter to make sure it’s not too cold for them.

Bad points:
1. It takes longer to fill the bath than when I had a full tank of hot with the previous system.

2. I’m £3k worse off, although this is already being recouped through savings in my energy bills. I really wish I’d done it sooner.

Horrible old fire, modelled by Billy:


Pretty new stove, modelled by Sneaks:


If your concurrent heating/water requirements are low (my house is a 2 bed semi, shower is electric, seven radiators) and you can afford it I would say go for it. You'll start saving on your energy bills as soon as you've had it installed

Thanks guys.

Sigh! I STILL don't know. I literally flip back or forth on a daily basis. Sometimes even several times a day! My OH doesn't want to change boilers as we do have an awful lot of other things to pay for in the house at the moment, and he doesn't think it's a priority.

I'm still swaying towards it. We have an old gas fire like yours Sneaksy (love the whippet remote story!), but it's never ever used as I'm sure it's unsafe and needs ripping out. We have a relatively modern boiler in the kitchen, but it must be several years old at least.

I think our demands could cope with a Combi. We have 2 ( and a half!) bedrooms, 8 radiators (but only 4 are ever used regularly) and currently only 2 people. Even if we have kids at some point, we still only have one bathroom - unless we can ever afford the much dreamed of loft conversion, then there might be a small en suite but I'd probably install an electric shower.

I just don't know what to do. I'd certainly like to save on heating bills as it does worry me. And I just feel that now is the best time to do it. I'd also like to upgrade to a power shower, which we could do with a Combi and water off the mains (otherwise we'd need a pump).

We've just hired a plumber to install our bathroom ( which is costing a fortune ) so I'll talk it through with him properly when he pops over. He is happy to install or not install a new boiler, it's up to us, but I really want to talk through the pros and cons. Problem is, with a new bathroom and boiler, we won't be far off spending £9000

ETA: whoops, you can't have a power shower with a Combi. But mains pressure should be good enough for a decent shower I think...?!

I think with the old hot water storage tanks, they can use a hell of a lot of electricity, and from a legionella and general cleanliness POV, they are pretty poor as householders do not tend to have their cold water storage tanks cleaned or the system disinfected and they do not have their hot tank flushed etc.

Combi boilers are far more energy efficient but the temperature of the water is governed too much by the flow of water from the outlet so they seem to take forever to get up to temperature. From what i've seen through my job, they arent as reliable as the old HWS system neither.