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In another thread , which it would be a pity to derail, @Ferdinand wrote:

 

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IMO GSHP is now very niche, and imo things like Rainwater Harvesting have mainly had their time, if you do a high quality fabric approach. SImilarly for complex control systems - if you can heat your whole house with a few kilowatts, then room stat timers cease to be economic.

 

I agree about GSHPs; the only use case I can see is an existing largish house in the countryside which is difficult to get up to a decent standard of insulation and so uses enough heat that the savings of a GSHP can be worthwhile.

 

But, I don't see what the building fabric has to do with rainwater harvesting. If you're on mains water then RWH is only every going to be, at best, marginally useful economically but you might still reasonably choose to do it for ecological reasons, particularly if you use a lot of water for gardening or whatever. Off mains water makes it more worth thinking about, of course. But that decision is quite independent of the building fabric choices.

 

In a well-insulated house complex control systems are not so useful from the heat distribution point of view but, conversely, the long time constants of such houses mean that there's more flexibility to grab the energy when it's available at lower cost. E.g., from E7 or PV. If you have multiple uses (space heating, DHW, car charging, …) then a moderately clever system probably is needed to make best use of what's available in varying circumstances.

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I am not sure exactly what you are asking.

 

I have my ASHP set to mostly only operate in the day. I don't have E7 and in any case I like a silent house at night, so prefer the heating to only operate in the day when it can use any PV generation that is going.

 

I have never seriously thought that rainwater harvesting has any real use if you have mains water available, except perhaps a small cost saving if you are metered?

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I'm not asking anything; I'm replying to Ferdinand's points which I disagree with, slightly.

 

 

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Rainwater harvesting is an interesting subject.  I looked at doing it initially, and quickly discovered it's not as easy to do properly as I thought.  The need to remain compliant with the water regs, together with making the system both affordable and reliable, with a minimal need for ongoing maintenance, poses a few challenges.  None insurmountable, but it was definitely something best designed in to a new build, rather than added as an afterthought.

 

In the end I dropped the idea because it was pointless, once we'd decided to have a borehole.  There seemed to be no merit in trying to capture rainfall before it hit the ground, when we were pulling (old) rainwater out of the ground for our main water supply.

 

 

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I was planning a rainwater harvesting system but it was just too expensive.  Several thousand pounds plus the cost of the groundworker and plant hire to get it done.  I shall be sticking with water butts around the greenhouses for watering the plants.

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I looked at rainwater harvesting; financially it didn't stack up (particularly as we're off mains sewage, so no sewerage charge).  The environmental aspect is interesting though, but on the basis that Anglian Water can recycle water on an industrial scale far more efficiently than I can, I'm happy to contribute by buying it.  A couple of thousand litres of rainwater might let you water the garden for a while during a hosepipe ban though...

Edited by Roundtuit
typo

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We use a large amount of water as we have large koi pond which ‘im indoors likes to partially empty and refil every few months.  We also have a large kitchen garden which requires a lot of watering in the summer.

We were intending to install a rainwater harvesting system.  However, the 2 people that we know that have them, have both had continual problems with them.  One has needed a new pump every year, the other just gave up trying to keep it running.  We have decided that when we have a digger on site, we are going to dig a well that he can put a submersible pump down, to water the vegetable garden every night.  The well will be in a shed that we can keep locked so that it is safe.

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Our 1930's house in Oxfordshire had a well in the garden, originally the water supply for 4 houses or perhaps more (4 pipes exited the well)  It was just ground water and you could look down it to see the level of the water table varying throughout the year.

 

We had a pump down it for watering the vegetable plot, and also used it as the soakaway for rainwater when we built the extension.

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10 hours ago, JSHarris said:

Rainwater harvesting is an interesting subject.  I looked at doing it initially, and quickly discovered it's not as easy to do properly as I thought.  The need to remain compliant with the water regs, together with making the system both affordable and reliable, with a minimal need for ongoing maintenance, poses a few challenges.  None insurmountable, but it was definitely something best designed in to a new build, rather than added as an afterthought.

[...]

 

I started off bright-eyed and bushy-tailed about rainwater harvesting.Tiggerish you might say.

 

Now, I just want to put the necessary internal piping in, blank it off,  and wait until after the main build has finished.   If I then suffer a @Stones - type urge to do some more , I can finish it off.  We intend to encourage more GCN activity, so it'll be brilliant to be able to keep a gravity-fed reed bed / pond topped up from a rainwater harvesting tank.  They are already stirring. Two dead on the road outside this morning. 

 

SWMBO and others are already asking me what I'm going to do with myself after the build.  There's a watershed moment if  ever I saw one.

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33 minutes ago, recoveringacademic said:

SWMBO and others are already asking me what I'm going to do with myself after the build.

I could never imagine that far ahead when I was asked that question.

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I had a planning condition on providing a modest amount of RWH - water butts would have sufficed but were not to my taste. Given we had a concrete box already in situ and were able to route the rain water system to it, putting 4 IBCs in it and hooking them together was peanuts (thanks to all who helped advise on the method).

 

Will be used in extremis during the summer but I guess that even 4000l would go quite quickly in a sustained dry spell so probably fairly pointless in all honesty :) but was a fun side project and helped a bit with the water usage calculation that BC require.

 

The systems that allow RWH to flush loos etc are quite complicated to meet the regs, require their own plumbing system internally and just seem to add cost and complexity. They also need mains back-up incase it doesn't rain and there are valid health concerns about bacteria etc from bird droppings. 

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How far can planners go with these conditions

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Just now, Oz07 said:

How far can planners go with these conditions

 

My condition was quite modest - 45l or something - but there had to be some provision. I suppose you could ignore it on the basis that they wont check - which is not an unreasonable assumption.

 

 

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I'll just wait for @Onoff to find this thread. 😎:ph34r:

 

But for now I am off to collect a person from hospital.

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45 minutes ago, Bitpipe said:

but was a fun side project

 

There you go, that's me happy! :)

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when I mentioned RWH to an architect (in the good old days when I thought we had a plot...) he was quite dismissive of using them for the hosue toilets, even though he is veyr keen on 'eco' builds.  he said in his experience with the few he knew, everyone said you spend more  money on cleaning products as the toilet goes brown quicker and so it wasnt worth it. 

I would have liked it for the garden if nothing else but if we did it, it would be a homemade version with advice from here.

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