We currently have a 15 year old Vokera combi boiler. We currently have one bathroom and the shower just runs off the bath mixer tap and is ideal for what we need. However it sometimes struggles to fill a bath with hot water.
We are putting an extension on which is going to add an en-suite and a downstairs w/c as well as morea study, bedroom and family room so obviously more radiators as well.
What type of boiler should we go for? On doing research there seems to be different camps saying bigger combis, or the newer condensing type that have a hot water tank but much more efficient.
One of the showers will probably be electric so wouldn't imagine that both would be running off the one boiler at the same time. Dishwasher, washing machine are both cold fill.
I got the combi at the time as this was the "new" way to go, no need for hot water tanks and surely you can't get more efficient than only heating the water you need? But a lot of blurb on the new systems with tanks say they are super efficient as well?
Whats thoughts of the experts on here? Is Mr Devon within our midst yet?
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Bobby... not an expert but just going through the same thing.
Our system was installed new 16yrs ago and is a conventional setup with open vented hot water cylinder in the airing cupboard, pump and 3-way motorised valve. The boiler however was a £40 used cast iron type and about 8yrs old then. Now with the boiler some 24yrs old (and never having spent anything on it) its just started to leak so I've done all the research and decided to stick with the existing system and just fit a high (A rated) efficiency condensing boiler.
We are lucky that this qualifies us for the £400 scrappage allowance.
It's a personal thing but we like an airing cupboard that's warm so decided to keep the tank. Also unless the combi boiler is very powerful you get the issue you mention... poor hot water performance.
It is my impression too that the combis can be less reliable.
We've just gone for an over bath elec shower and have a dishwasher so the stored water is rarely drawn off in large quantities.
As for make we agonised over this and in conjunction with a trusted fitter chose a Gloworm with a stainless heat exchanger as a mid range quality/price.
Hope there's something of interest in there.
There is a heating/plumbing forum at DIYNot with a lot of pros posting but to be honest they are quite short with Joe Public and don't always give good advice willingly.
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I think it very much a case of go with the configuration you have.
I, for example, had an indirect hot water system (thats the cylinder to you and me) so when the boiler was changed it was a condensing type to the existing indirect system.
You clearly have no cylinder, so unless you want one fitted, and the space it takes to have one, and the added work and cost, you should go for a combi with a higher output.
As a personal thing, I hate combis. Too complex, always going wrong, and in my eyes always struggle to do the job properly.
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Slight drift from the OP but ... I called a 'geezer' in yesterday to service my 18 year old Glow-worm Hideaway 60.
He did a thorough job and said the ole broiler should be good for a few years yet.
I chatted him about bunce 4 boilers (scrappage) + condensing boilers + combi's.
He reckons that a new boiler would save about 20% per annum, but these new boilers don't last more than 5-7 years (don't shoot the messenger)
My existing boiler uses the old chimney as its flue but a new boiler would require a complete new flue + additional plumbing to drain orf the condensate, or he even mentioned a soak-away may be required for that.
We also like a warm airing cupboard for some strange reason, so I've kicked that idea into the long grass (for now)
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>> We also like a warm airing cupboard for some strange reason so I've kicked that
>> idea into the long grass (for now)
Thats all true, you can get them to last 10 years with some careful maintenance and good instalation work.
however when yours goes, you are gonna have to cope with the new flue and condensate drain.
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>>> however when yours goes, you are gonna have to cope with the new flue and condensate drain <<<
The other thing to consider A - I mean Zero, is how long one is going to stay put, we may well be on the move (again) this year but - if we do decide to 'put down roots', then I'd be looking at a Worcester Bosch jobbie.
There are some very cheap Italian made boilers on the market c£500, I can't recall the name but they begin with F (but don't come in Rosso red).
They would be ideal for someone who intended to move house within a few years.
Fitting a new boiler is not rocket science, neither is it DIY I realize that, I've a mate who built (most of) his own extension, he recently fitted a large conservatory with glazed roof and ... he even fitted a Rayburn + tanks & rads, obviously he'd get a Gas safe reg. chappie to run the rule over it ... there are obviously rules against these things, but this is Cornwall.
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As part of upgrading our house we just changed our heating system completely. I did consider combis, and a plumber did nothing but sing their praises. In our case with a number of bathrooms, teenagers with long hair and so on I knew that combis would not be able to cope with the demand. Basically you have around 30KW of on-demand heating. That's 3 x an electric instant heater, but still not really enough for a really powerful shower, or shower + bath etc. It's ok for a smaller flat or house though and efficient because you are only heating what you use.
It would be complete disaster with underfloor heating because that needs heat at 35 deg instead of 65 deg of a conventional boiler. OK there are mix down circuits, but your boiler ends up firing 24/7 and you can end up with a massive gas bill.
If you go conventional condensing boiler, you then need a hot water tank + header tank. You don't get pressurised mains hot water with these unless you opt for a pressurised tank (and no header tank). These can be dangerous because you have a load of pressurised hot water in a cylinder. They have to be serviced annually by a qualified plumber.
We went a different route completely and installed a heat bank. Basically this is a very large hot water tank where the tank contains the central heating water, not the water that comes out the taps. You then have a load of pumped circuits where the gas boiler heats the top down (on a patented mix down). So hot water within 3 mins of cold even though the tank is 400L. It relies on hot water in it all the time and because of convection tends to be much hotter at the top than at the bottom. This fact is used for all the circuits that you attach to this tank. In our case we have in total:
Inputs
------
- a pumped gas heating circuit (fed at top and mix down with cold at the bottom so that the return to the boiler is always at 35 deg and keeps the gas boiler in condensing mode - i.e. more efficient. We have a Worcester Bosch Greenstar 100K BTU). The boiler's job is just to keep the tank hot. As the output is basically buffered by the tank, the boiler rarely fires, but when it does it runs for a long time. This is the most efficient thing one can do.
- a pumped solar power circuit - directly fed into the tank near the very bottom. Solar controller brings on the pump when temp at panel is above that at the bottom of the tank. It only cost controller + pump to add solar power (i.e. around £200 more). So no brainer to add solar. The panels were another £1500 for some 90 x 56mm tubes providing some 4.5KW of heating when the sun is shining of course. Payback will be within 2 years. Plumbing it in was just running the pipes to panel and programming the controller.
- a convection driven solid fuel circuit - from back boiler on wood burner (8KW). Just puts some residual energy into the system.
Outputs
---------
- a pumped upstairs radiator circuit - taken from near the top of the tank so that rads are hot. (controlled by room stats)
- a pumped underfloor heating circuit. This feeds the manifolds directly without mix-down because the tap for this is in the middle of the tank where the output is cooler. It has an adjustable mix down anyway.
- domestic hot water - a pump takes the water from the top of the tank and passes it through a heat exchanger (like the combi boiler ones) but rated at 160KW where it heats the cold water main to provide mains pressure hot water. There is a thermostatic temperature control to give 45deg water provided the tank is above this. The tank has so much energy stored in it that you can turn on all taps full blast and have hot water at all. Mains water goes through an electronic pressure switch that comes on when you open a tap and brings the pump on.
So basically best of all worlds. These systems are pretty new to the UK. They have been out in Germany and other places for a while, but over here no-one really seems to know about them. Certainly the plumbers we met didn't seem to have a clue because it is a really different concept. However, if one has multiple heat sources, underfloor heating, renewable energy (solar, heat pumps) etc. it really is the only solution as it seems to have all the advantages of other systems without any of the disadvantages.
We got ours from www.heatweb.com.
The MD there is very knowledgeable and very smart. I think the company is a bit more organised now than when I dealt with them.
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Interesting. If we get the house we've looked at it will need a new boiler etc. Might not go for it now though.
I thought combi but know they have downsides. Last house our plumber tried to talk us into a combi instead of just a replacement. The replacement was massive and maybe could have been more efficient.
Always thought he wanted to get more work to take out header tanks, water tanks etc.
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You really expect 1700 quid solar payback in two years? I really doubt that.
You dont need pressurised hot water, gravity is fine, and where you need pressure - in the showers - have a 1.5 bar pumped circuit.
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The condensate drain from a condensing boiler is a bit of a pain. We are replacing the toilet at the same time in the room where the boiler is situated so hope to make some provision for a boss on the soil pipe. Otherwise it means taking the 22mm plastic condensate pipe outside to the nearest drain (or digging it's own soakaway). If this pipe goes outside then it will need insulating to prevent freezing in cold weather because if it it gets blocked with ice the boiler will shut down (not even a limp home mode!).
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>> You really expect 1700 quid solar payback in two years? I really doubt that.
ok ok - maybe a bit exagerating I know. ;-)
Mind you as a rough calculation :
I don't know what gas costs per KWh as I can never make sense of the bills I get. But say it were electric at around 10p/KWh. On a sunny day that means 5KW of solar is around 50p / hour - say 4 hrs gives approx £2/day for say maybe half the year - that's about £500 per year. So more like 3-4 years. Still not too shabby.
>> You dont need pressurised hot water gravity is fine and where you need pressure -
>> in the showers - have a 1.5 bar pumped circuit.
Well that is an option and a good one in many situations. You can either have pumped shower circuits or whole-house circuits. In the case of a shower pump you also have to have a separate shower circuit.
The other thing is that many modern fancy taps only work well with pressurised water. We had some nice Hansgrohe taps in an upstairs bathroom and one would have to wait for ages to get hot water out of them. Usually I gave up waiting. (Ok I know you can have live hot water circuits to solve this too). But then it also delivered only a dribble on hot while cold (on mains) was a jet - even with all the adjusting flow regulators removed on the hot side. Now the tap works in a nice balanced fashion and I am still not used to having hot water coming out of it. The thought of a whole-house pressure pump just didn't appeal.
The only thing is that we also had to renew the cold water main to the house as this had to go from 15mm to 25mm. Lots of digging for someone...
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car4play says that you get 10p per kWh.
On the other site there was discussion about a new scheme from April 2010 which will give you about 50 or 60p per kWh consumed from your solar system.
Sadly or not sadly, search on the other site is useless but there must be sources of that information from other than the other site.
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You are referring to the new government scheme for getting money for electric you generate regardless of piping it back into the grid (for which you get more anyway).
tinyurl.com/lunyhf
Might be a useful link? Not read it all.
Last edited by: welshy on Sat 27 Feb 10 at 13:10
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>> car4play says that you get 10p per kWh.
I was only making a comparison with purchase price of electricity only because I don't know the equivalent in gas.
The other scheme you are refering to is for PV (Photovoltaic) solar energy. We have solar heating.
And yes, on this (PV) the government are giving some crazy money away at the moment. I haven't completely checked, but there are incentives for installation, annual payment thereafter and around 40p/KWh you generate from solar. They are doing all this because it helps meet their targets (don't you just love them) for energy from renewable sources. So yes, you can buy for around 10p/KWh and sell to them at around 4 x this amount. I can see some people storing and reselling back - but that would be dishonest and wicked of course.
They used to pay this on excess energy, so it would be worth turning everything off just to sell them some electricity, but I understand the new rule applies for all solar electricity generated whether you have any excess or not.
Personally I think all this PV stuff is nonsense. The solar heating panels are around 85% efficient whereas PV are between 15-20% - and cost the earth. At the cheapest £400 buys you a metre square panel for about 200W. So you need £2K for 1KW. The other thing also not mentioned is that if a shadow is cast over the panels - even an aerial wire - this stops the cells in that area working so well and has the same kind of effect as putting a dead battery in series with a load of good ones. i.e. the drop in performance is far worse than just the loss of area in sunlight.
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>> So yes, you can buy for around 10p/KWh and sell to them at around 4 x this amount.
The are going to pay the 40p for generating it. You're not selling anything back. You get this money and you get to use the electric too!
As you say it's so they meet some target or other. Like the energy companies about to fail to reach some target so shipped millions of energy saving bulbs recently to offset against their failings. It was cheaper to post out the bulbs than to fail some target or other. There was apparently a deadline after which they could not use this tactic.
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It may sound a lot but I don't think it's viable - as said above the panel are v expensive, even if you fit them yourself. I worked out that about £15k worth of panels would generate me an net annual income of about £900. Unless I worked it out wrong, or my memory is bad, the £15k of panels generate about 2.5KWh, which would not be enough electricity to be self sufficient at any time other than summer days. They provide nothing at night (so you either do without or then get into expensive and bulky storage) and diminished output during cloudy/dull weather. While the panels are virtually maintenance free for their life (25 years est) the converter may need replacement at about 15 years. So, without taking into account inflation, you would break even after around 18 - 20 years. (You could also make sure that you do stuff like your washing/dishwashing during teh day, and install some night storage heaters. Or you could do what I did this year - just turned off unnecessary lights around the house - my consumption has dropped 13.6% over the year!)
And back on topic, I have a voucher for a replacement boiler., My next door neighbour is qualified to fit it, and has quoted me around £2k. With the limited savings it will give, and short boiler life (he reckoned no more than 15 years) I've gone off the idea.
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I didn't think you could use who you liked for the boiler replacement vouchers - so most are inflated prices. You need to send off the voucher plus the invoice to get your £400 back.
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We're using the £400 scrappage voucher. The installer has to be Gas Safe (what was CORGI) registered.
Unless there's extra work like converting to combi £2k is a lot for a boiler swap from a contact like a neighbour. Mine will be some £600 less than that! A boiler is about £600 and no way do I want to pay a gas safe plumber £700 a day for his time! I do get the impression some guys are trying to cash in on scrappage by saying when they estimate... of course you get £400 off that from the government.
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My boiler swop cost 1300 quid. That was two days work as it needed to be moved as well.
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Getting stuff done always seems to cost a lot around here compared to other parts of the country. £2k was for pretty much straight replacement (plus flue), plus making it a closed circuit system, putting in a magna-something (which was already discussed elsewhere). The grant would have made it £1600. I don't expect my neighbour to do stuff on the cheap for me after all, it's his living.
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Hey - I am in surrey. It dont get much dearer to get things done.
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When we last bought a boiler - a big floor standing one for a big house it was about £1200 fitted I think. Straight swap. It was about 7 years ago though.
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>>
>> Personally I think all this PV stuff is nonsense. The solar heating panels are around
>> 85% efficient whereas PV are between 15-20% - and cost the earth. At the cheapest
>> £400 buys you a metre square panel for about 200W. So you need £2K for
>> 1KW. The other thing also not mentioned is that if a shadow is cast over
>> the panels - even an aerial wire - this stops the cells in that area
>> working so well and has the same kind of effect as putting a dead battery
>> in series with a load of good ones. i.e. the drop in performance is far
>> worse than just the loss of area in sunlight.
>>
>>
Those figures sound reasonable / optimistic for PV, I did start digging out my old notes from work on the subject when it came up on the old site to see if the numbers stacked up. Efficiency of PV gets worse as well when you consider the angle of the sun on the panels, plus the electronic control of PV to regulate the output isn't trivial.
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>>The other thing is that many modern fancy taps only work well with pressurised water.
Yep that's something rarely made clear that we've discovered to out cost. We have gravity hot and cold in the bathroom and the new *style* mixer tap on the basin has minimal flow. They are made with far smaller bore to the waterways than the good old taps of 20yrs ago.
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Maybe the flow is poor to encourage using less water. Sounds crazy to me. I was not aware of this but thanks for pointing this out. We might be after a new bathroom and kitchen in the next house.
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>> >>The other thing is that many modern fancy taps only work well with pressurised water.
I think because all the fancy good taps tend to be German and they have mains pressure for water over there. Even some of their loos don't have cisterns but rely on the pressure directly to work. We have a pile of regulations stopping us doing that kind of thing in case the main drinking supply gets contaminated etc.
And as you say the bore is miniscule once you get down inside the tap itself.
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Having just had to purchase some taps for the bath, I made sure they were "low pressure"
For interest, I had to purchse new taps because the old cheap mixer broke to bits when I tried to take apart the mixer bt to descale it. 3/8 inch solid brass spindles have no torsion strength at all.
Last edited by: Zero on Sat 27 Feb 10 at 15:04
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Continental taps are designed for both hot and cold being supplied at mains pressure and are usually small bore-their mixers mix within the tap unlike UK ones that mix in the spout.If a continental mixer is used in the UK,one-way valves must be fitted in the supply pipes to avoid contamination of drinking water supplies.
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Lots of good reading and info on here so far - keep it coming!!
But I think I will avoid the solar panels - it is Scotland after all!
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as both my hot and cold bathroom taps are gravity fed from the water tank, there cant be any drinking water contamination.
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>> as both my hot and cold bathroom taps are gravity fed from the water tank
>> there cant be any drinking water contamination.
>>
I thought I read somewhere, new regs say hand basins must have the cold water supply from the mains.
Last edited by: car4play on Sat 27 Feb 10 at 15:58
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Our boiler was isntalled in 1984 it traditional kind. The only thing that has ever gone wrong with the system in 26 years is the pump.
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You are required to have at least one tap in the house-usually the kitchen sink-fed directly from the mains supply so that there can be no contamination.What's in your cold water tank? dead mouse,beetle,spider???Hand basins,probably must comply-after all,most people clean their teeth there.
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There is no building regs that say you must convert existing hand basins. Anyway, my hand basins dont have mixers, and you dont clean your teeth in the bath or shower.
And its usually a dead pigeon,
Last edited by: Zero on Sat 27 Feb 10 at 16:34
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If your tank's covered,it's unlikely to be a pigeon;just something that climbs up the overflow pipe.
Last edited by: jc2 on Sat 27 Feb 10 at 16:54
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Cider makers - it has been said - put a dead rat or pigeon in the vat to improve the flavour.
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Is it true you are supposed to throw a dead sheep in your septic tank to get it started?
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What the sheep or the tank ?
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the tank - the sheep is scrappage.
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>> Is it true you are supposed to throw a dead sheep in your septic tank
>> to get it started?
>>
www.shelterpub.com/_shelter/ssom_additives.html
"A homeowner does not need to add a stimulator or an enhancer to a septic tank that is designed, operated, and maintained properly—naturally occurring bacteria are already present within human fecal matter. Contrary to popular belief, yeast, dead chickens, possums, or raw hamburger do not need to be added to the septic tank."
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>>What's in your cold water tank? dead mouse,beetle,spider???
>>
Nowt cos it has a bye law kit fitted.
Perhaps that is why the loft tanks are sometimes called Coffin tanks ? :-)
( yes I do know the real reason )
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Another satisfied Heatweb customer here. We've had one of their heat banks for about 5 years now and it's very good. Mains pressure hot water all the time, fills a bath in very short order and gives you really good showers without a high pressure cylinder sitting there with its maintenance requirements. We got one with all the solar gubbins inside but haven't got panels on the roof yet.
I'd like to say the same about the boiler I chose to go with it, but it's currently not working. I got a MAN Heiztechnik one ( www.mhg.de/ ) and it's not been brilliant - a couple of breakdowns since installation and it was not cheap. To be honest I don't think I've had a typical experience in that when it arrived the cover was dented and I asked the supplier to take it back. They said they hadn't got a replacement in stock so it would be about 4 weeks for a new one, we were in the last stages of a long building project and to hold things up for that long would have been a nightmare so I allowed myself to be talked into fitting the original one. I got them to extend the guarantee to 4 years but I've never really been convinced by it and I'm not sure that it's ever really worked to its full potential even though one of the suppliers own technicians came to commission it.
I'm interested that your heating circuit seems to be connected to the heat bank. I don't think ours is.
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"If you go conventional condensing boiler, you then need a hot water tank + header tank. You don't get pressurised mains hot water with these unless you opt for a pressurised tank (and no header tank). These can be dangerous because you have a load of pressurised hot water in a cylinder. They have to be serviced annually by a qualified plumber."
While I'm no expert, I find this extraordinary.
Fully pressurised systems have been in use over the continent for years. The pressure is around 1 to 1.5 bar - not particularly high. In the ten years I have lived with such a system (installed as new in a house now 15 years old) I have never heard of any safety issue. As for the assertion that such systems have to serviced annually - none of the various heating engineers who have attended have ever suggested it was necessary. (I can't see what you would do to a pressurised system that you wouldn't do to a header-tank system.)
I have just had the old boiler replaced with a new condensing type; virtually nothing on the existing set-up needed changing - same cylinder, valves, pipes, except for a little re-routing near the boiler itself.
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When I was investigating this topic I was informed by several sources that I would need either building regs. approval or engage the services of an approved installer and annual maintenance to install a fully pressurised cylinder. That's one of the reasons I opted not to, although the person who installed the bathrooms had recently done the certification course to be an approved installer.
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A couple of points - If you are in receipt of certain state benefits you may well qualify for a total grant, up to IIRC GBP 3500, for central heating, subject of course to varying requirements.
This is administered by an agency (!) called Warmfront. Great you say - until you realise that Warmfront have run out of funds and despite promising installation by a date, absolutely cannot proceed until more readies are pumped in from Government.
This farcical situation led to a family member freezing over last winter as other arrangements were not put in hand to install heating, on the basis that one cannot self organise installation and reclaim the cost - it all must be dome by a Warmfront approved & selected installer.
Patience running out, other arrangements were made and a private deal struck for an Ideal Espirit 30 combi boiler +5 rads (4 double & 1 single, plus connecting a heated towel rail) for just over GBP 2K. This is in a small Victorian terraced workers house, involved much furniture and carpet moving and floorboard taking up, too.
A good deal , I think AND there's a wireless remote control thermostat unit!
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>> This is administered by an agency (!) called Warmfront. Great you say - until you
>> realise that Warmfront have run out of funds and despite promising installation by a date
>> absolutely cannot proceed until more readies are pumped in from Government.
My neighbour has just had his oil-fired central heating system replaced through Warm Front. I hope for his sake that he gets the grant. www.warmfront.co.uk/
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I havent read other replies, ill just add what I know about the latest combi boliers.
I have an A-rate Baxi combi, just over a year old. The British Gas guy who serviced it rated it very highly and I have to agree with him based on my gas bills.
We keep the thermostat to an even 19c, we have two showers a day in the house, which is a detached 3-bed and our WINTER gas bill was £70 ( Nov-end Jan ). Now given how cold it was, I dont think you could ask for much lower bills than that really. I imagine it will be very little indeed in warmer parts of the year.
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>>> our WINTER gas bill was £70 ( Nov-end Jan ). <<<
£70!! your meter must be wonky ;-)
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Nope, all working. Previous owner of the house had similar bills, it was a point of discussion before we bought the house. It helps to have it well insulated, which ours is - our heating is only on for a couple of hours a day and then unless you leave windows and doors open, it stays pretty much where it is without needing any top-up. Sometimes it has an hour blast in the evening if we are feeling cold.
When we had to have the heating turned off due to a leaking radiator, the house dropped to 16c only over two days despite it being 5c outside. Gotta love progress.
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>>>Gotta love progress<<<
Too true stu ... I think there should be a house scrappage scheme, new house building has slowed to a halt due to the recession, many folk in allied trades - roofers, carpenters, brickies, elec etc., etc., are suffering financial hardship, and having their home repossessed in some cases.
Sure it would cost £billions and £billions and £billions, buy at least it wouldn't be thrown down the pan like the £b's & £b's wasted on illegal wars and bankers bailouts!
Our 1930's house is about as energy efficient - as a tent, and the boiler has a wasteful pilot light that is on 24/7/365 nice house though :)
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>> I think there should be a house scrappage scheme
YOU Vandal!
Houses should be preserved as much as possible in the orginal state.
I have a early 1930 bungalow. It has its original floorboards on display, orginal internal doors (stripped and waxed) even down to the orginal bakelite door handles. YOu dont own a house you maintain it for others - sometimes as history.
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>>>YOu dont own a house you maintain it for others - sometimes as history. <<<
Oh, but I quite agree Z, some (many) houses though could do with a visit from the Demolition Man.
What I quite like is a new build with the character of a period house, but with 21st century energy efficiency.
I'm not mocking mock, but I don't really mean 'mock'.
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>> ......even down to the orginal bakelite door handles.
>>You dont own a house you maintain it for others - sometimes as history.
>>
Somewhere I have an unused very old boxed bakelite C/H thermostat to dispose of.
Suit a Surrey bungalow owner?
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will be in touch next week H, when I get back from Seville. Off this afternoon.
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This seems like an amazing deal (to me) ~ preview.tinyurl.com/yja4wfq
Wood knot cover Scootland or Kornwall though.
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Boiler replacement - which kind? - Fenlander
