dogman Posted January 14, 2017 Share Posted January 14, 2017 Morning, has anyone installed a WWHR system i have looked at different options but are put off by the cost and efficiency Cheapest non sap system was about £500 and was probably the best as it was a tank rather than a tube. In my simple mind the tube systems only work if you are drawing water at the same time as draining waste (ie a shower not bath) where as a tank has an element of storage Opinions and real world example please. Link to comment Share on other sites More sharing options...
joe90 Posted January 14, 2017 Share Posted January 14, 2017 I always remember Tony's answer some time ago, don't drain the bath after bathing, let its heat dissipate into the room then let it go. The simple ones are always the best. Personally I discounted them way back as not having a good payback. Link to comment Share on other sites More sharing options...
Crofter Posted January 14, 2017 Share Posted January 14, 2017 I've done a bit of reading on this, with the notion that I would like to build a DIY version using copper tubing. To do it according to regs you need to have so much separation between the ingoing/outgoing flows that heat exchanger efficiency suffers. The reasoning for this is to prevent the dirty outgoing water from contaminating the clean supply. You're correct in identifying that a different approach works for showers vs baths. For my own use, I would be looking to give an instant boost to the incoming supply to a shower, which necessitates a heat exchanger rather than a tank. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 15, 2017 Share Posted January 15, 2017 If you want to save energy, take shorter showers at a lower temperature, got to be easier and cheaper. The separation issue is a good reason to have a batch system using a couple of tanks, one for the waste and one for the incoming water. That way you can use a simple coil heat exchanger in each tank and a small pump. It can then run for as long as it needs to equalise the temperatures. You may find that a simple PV module or 2 and a cheap 500W heating element does the same thing. Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 15, 2017 Share Posted January 15, 2017 Seems a lot of hassle for little reward to me, especially the tank option, not to mention cleaning and maintenance headaches. DIY sounds like it would give you a sense of achievement for less bucks, but not much more. Iirc, @jack has these fitted. Any performance statistics anyone? Link to comment Share on other sites More sharing options...
jack Posted January 15, 2017 Share Posted January 15, 2017 Just typing this as you posted actually Nick. We have one. Long payback, yes, but I reckon 90+% of the hot water use in our house is showers. Baths are extremely rare - maybe once a month at the moment. We have 4-6 showers a day, 2-3 of which are kids old enough to shower themselves but not old enough to get out of the shower without a lot of cajoling. Even taking a conservative estimate of efficiency, we save a lot of hot water with WWHR (reducing energy consumption is good, surely? ). Equally importantly, we get a lot more out of our tank. We have a 250L UVC. With our particular water usage patterns, I suspect it's like having a 350+L tank. As for just taking shorter, cooler showers, no thanks. A decent shower is one of the few luxuries I allow myself. I already keep them pretty short and I shower at whatever temperature is comfortable. We don't have high flow showers. One thing I don't have is comparative performance numbers, because the unit was installed before the house was occupied. I do know we've never run out of hot water in over a year. Can't say whether that would be true if we didn't have the unit. Link to comment Share on other sites More sharing options...
dogman Posted January 15, 2017 Author Share Posted January 15, 2017 @jack what manufacturer did you go with. There are only half a dozen SAP listed. Link to comment Share on other sites More sharing options...
jack Posted January 15, 2017 Share Posted January 15, 2017 I believe it was this one. Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 15, 2017 Share Posted January 15, 2017 14 minutes ago, jack said: (reducing energy consumption is good, surely? ). It is......and don't call me Shirley Link to comment Share on other sites More sharing options...
jack Posted January 15, 2017 Share Posted January 15, 2017 Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 15, 2017 Share Posted January 15, 2017 You read my mind ? Link to comment Share on other sites More sharing options...
dimpsy Posted January 15, 2017 Share Posted January 15, 2017 I would think that a talented Welsh plumber could make this with some left over scrap copper, and then retire, think the cost must be in the design not the materials http://powerpipehr.co.uk Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 15, 2017 Share Posted January 15, 2017 Crikey. 2.4 m mounting height ! @jack, how is yours positioned for cleaning / maintenance / replacement etc? 67% ( manufacturers quoted efficiency ) isn't to be sniffed at TBH. Different models suitable for first floor showers ( 2m long vertical tubular type ) with other models specified for ground floor ( big shoe box basically ). Interesting that it says NOT to insulate the unit itself ( pipework to be insulated ), unit to be kept below 25oC ambient, and ( preheated side ) pipework to be kept 3m or shorter ( to achieve max efficiency ). Mounting and locating this unit should really be included as a design consideration, before your builder gets the tools out . Link to comment Share on other sites More sharing options...
Crofter Posted January 15, 2017 Share Posted January 15, 2017 When I looked into this there seemed to be two approaches- a vertical pipe where the outgoing water swirls down the walls, and a spiral tube underneath the shower tray. Which sounds like a good way of getting cold feet, IMHO. I have contemplated building something akin to a conventional heat exchanger- basically copying what a marine diesel engine has- using microbore copper piping. There would need to be a good filter and a high level overflow, and cleaning hair out of the filter would probably be a daily task. Link to comment Share on other sites More sharing options...
Onoff Posted January 15, 2017 Share Posted January 15, 2017 Could you..... On the basis that UFH is so efficient, run the waste through a loop under your slab and hold it there until the heat dissipates.....thus recovering some heat. Then let it exit via a small turbine to get some hydro electric power.....making use of the kinetic energy. Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 15, 2017 Share Posted January 15, 2017 17 minutes ago, dimpsy said: I would think that a talented Welsh plumber could make this with some left over scrap copper, and then retire, think the cost must be in the design not the materials http://powerpipehr.co.uk ????? @jack how much was your unit if you don't mind, please? Link to comment Share on other sites More sharing options...
Onoff Posted January 15, 2017 Share Posted January 15, 2017 How about this for only £170? http://www.utilityfreeliving.co.uk/shower-water-heat-recovery/ Link to comment Share on other sites More sharing options...
jack Posted January 15, 2017 Share Posted January 15, 2017 34 minutes ago, Nickfromwales said: Crikey. 2.4 m mounting height ! @jack, how is yours positioned for cleaning / maintenance / replacement etc? 67% ( manufacturers quoted efficiency ) isn't to be sniffed at TBH. Different models suitable for first floor showers ( 2m long vertical tubular type ) with other models specified for ground floor ( big shoe box basically ). Interesting that it says NOT to insulate the unit itself ( pipework to be insulated ), unit to be kept below 25oC ambient, and ( preheated side ) pipework to be kept 3m or shorter ( to achieve max efficiency ). We have high ceilings downstairs so the mounting height was okay for us. Ours is behind a full-height removable panel at the back of a drying cupboard in our utility room: I assume the 25 deg C ambient temp is to do with Legionella. We have several showers a day, so unless the house is left unoccupied for a long period, I'm not really concerned about this particular requirement (even if we go on hols, the temp in enclosed spaced will quickly approach the low-20s ambient of the rest of the house anyway). Our plant room would have been a better place for the unit, as it's just on the other side of the drying cupboard, but the plumber was very reticent to install it there given it was likely to be well above 25 deg C for long periods of time. 27 minutes ago, Nickfromwales said: @jack how much was your unit if you don't mind, please? It's been quite a while, so I'm not sure. I believe it was around £600, but that's a complete guess. Powerpipe (the main competitor to the one I used) has pricing on its website Link to comment Share on other sites More sharing options...
Crofter Posted January 15, 2017 Share Posted January 15, 2017 39 minutes ago, Onoff said: Could you..... On the basis that UFH is so efficient, run the waste through a loop under your slab and hold it there until the heat dissipates.....thus recovering some heat. Then let it exit via a small turbine to get some hydro electric power.....making use of the kinetic energy. Don't forget to tile your bathroom with PV panels while you're at it... Link to comment Share on other sites More sharing options...
Onoff Posted January 15, 2017 Share Posted January 15, 2017 16 minutes ago, Crofter said: Don't forget to tile your bathroom with PV panels while you're at it... It's sourcing the sustainable energy floor tiles that's holding things up. Link to comment Share on other sites More sharing options...
Crofter Posted January 15, 2017 Share Posted January 15, 2017 27 minutes ago, Onoff said: How about this for only £170? http://www.utilityfreeliving.co.uk/shower-water-heat-recovery/ That's pretty much exactly what I was thinking of building. Thanks for the headsup on the website by the way- they have some interesting products. I've just emailed them about their single room heat recovery unit, which could be just the ticket for my wee house. Link to comment Share on other sites More sharing options...
Onoff Posted January 15, 2017 Share Posted January 15, 2017 4 minutes ago, Crofter said: That's pretty much exactly what I was thinking of building. Thanks for the headsup on the website by the way- they have some interesting products. I've just emailed them about their single room heat recovery unit, which could be just the ticket for my wee house. I've been looking at it for the bathroom tbh. That and the Ventaxia range that seems to double in price from the basic to the one with all the bolt on goodies like humidistats. Link to comment Share on other sites More sharing options...
jack Posted January 15, 2017 Share Posted January 15, 2017 Interesting unit. A couple of concerns would be: - corrugated pipes = higher likelihood of blockage/grunge build-up - stainless steel = good for longevity but heat transfer not as good as copper - looks like it would be difficult if not impossible to clean - looks like only a single wall construction. If so, doesn't building regs (but don't quote me on that - I'm no expert!) - the whole unit is only 60mm in diameter, and the waste water connections are 1.25" BSP fittings. This seems very small for a shower outlet. It also suggests that the gaps between the internal pipes in only a few mm. I can only imagine how little hair it would take to cause a blockage in one of these units. Link to comment Share on other sites More sharing options...
Onoff Posted January 15, 2017 Share Posted January 15, 2017 Just now, jack said: Interesting unit. A couple of concerns would be: - corrugated pipes = higher likelihood of blockage/grunge build-up - stainless steel = good for longevity but heat transfer not as good as copper - looks like it would be difficult if not impossible to clean - looks like only a single wall construction. If so, doesn't building regs (but don't quote me on that - I'm no expert!) - the whole unit is only 60mm in diameter, and the waste water connections are 1.25" BSP fittings. This seems very small for a shower outlet. It also suggests that the gaps between the internal pipes in only a few mm. I can only imagine how little hair it would take to cause a blockage in one of these units. Don't tell me about hair! Between the wife and daughter it's like living with a pair of Cousin Its! It's No.2 clippers all over for me! 1 Link to comment Share on other sites More sharing options...
Crofter Posted January 15, 2017 Share Posted January 15, 2017 12 minutes ago, jack said: Interesting unit. A couple of concerns would be: - corrugated pipes = higher likelihood of blockage/grunge build-up - stainless steel = good for longevity but heat transfer not as good as copper - looks like it would be difficult if not impossible to clean - looks like only a single wall construction. If so, doesn't building regs (but don't quote me on that - I'm no expert!) - the whole unit is only 60mm in diameter, and the waste water connections are 1.25" BSP fittings. This seems very small for a shower outlet. It also suggests that the gaps between the internal pipes in only a few mm. I can only imagine how little hair it would take to cause a blockage in one of these units. I think a decent filter would be a necessity. My DIY one was going to be longer and use copper. But I wouldn't be able to have the corrugated pipe surfaces. Edit to add: surely copper is adequately long lived, unless you're planning on showering in salt water or battery acid?? 1 Link to comment Share on other sites More sharing options...
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