Save Water Or Power? Looking Beyond Dollars.

[SmartieParts 12]

Since moving into my current home back in 2007, I've been frustrated with a dilemma. There is a financial aspect to my dilemma, but in my view it is more of an environmental quandary, and I turn to you folks for help it making a decision.First, I want to note that I live in the Okanagan... Canada's only desert (technically, though it is pretty green!). Water is, or at least should be, at a premium. There is a finite supply of it, yet collectively we use it like there's no tomorrow. Statistics show that we get far less rainfall than any other area of Canada, yet we use up to 160% more water per capita than the national average (primarily since we're full of golf courses and lawns that aren't part of Nature's plan for this region). So saving water is quite paramount.And that, in a nutshell, is one half of my equation.The other is more globally reaching. It is important for all of us, as citizens of this planet, to conserve energy as best we can. To be efficient with fossil and other fuels is rather important, I believe as I'm sure many of you do.What to do when the two are at odds?Now I come to the specifics of my dilemma. Since moving into this house, which is rather large (that's a whole other environmental debate that I know I'd lose, and rightfully so), I've been frustrated in particular with how long I have to run the water at any given tap or shower before warm water flows. Its rather unbelievable, really, how even in the middle of summer when the house is warm overall, I can count to a full minute at the kitchen sink before it is hot enough to do the dishes. In that time, I'm letting some 5 liters run down the drain. Now, is that water truly "wasted"? I'm no sure I know really. Some argue that it eventually ends up wherever it ends up and returns to nature via evaporation anyway. Yeah, well... fossil fuels are completely renewable too if you consider that all you have to do is wait a billion years and its all back! So I'm not sure that argument really "holds water" (excuse the pun). And if that were true, why is there such a campaign to conserve fresh water? So I do believe, even if I don't fully understand it, that letting the water run down the tap is a "bad" thing. A much MUCH lesser concern is that it also costs me money. 1000 liters down the drain costs about 35 cents... a travesty in its own right that its that cheap! So the financial cost of the water is trivial. The annoyance of waiting for hot water is a bit of a concern, but primarily its the environmental impact.So what can I do? Well, Google shows me that I should install a hot water recirculation pump. Basically it keeps circulating the water so the bit that's in the pipes (which is what's otherwise cooling and needing to be extricated before warm water can flow) is always warm. OK, that's fine and dandy. That solves that wasted water, but there are three things to consider if going this route.#1) The system itself has some environmental impact simply in coming into existence. That thing had to be made, and that took energy, etc etc. This obviously also has a financial cost of some $300.#2) The system takes some amount of electricity to run. I understand it is reasonably low. Electricity, being in BC, is also a rather "clean" energy so this part doesn't bother me so much. The financial cost is relatively trivial.#3) The hot water tank is now having to fire more often to keep the system temperature steady. The cooled water is pumped into the tank which needs to be heated to re-fill the lines (and so on). I imagine the increase in natural gas usage for this purpose is somewhat significant. I really don't know how much more gas it will use. I haven't been able to find any data on that, and probably because it would be vastly different from one system to the next. This is the part that concerns me the most Financially, I'll be paying for that gas. Environmentally, that's a fossil fuel being used that wasn't before. If it were just for my annoyance of having to wait for hot water, the environmental costs would be too high. But is it worth it for "saving" the water that otherwise goes down the drain?So what say you? Weighing the environmental aspects of the equation far above the financial (and the "convenience" factor falls in between), should I get the system and save the water but waste the electricity and gas? Or should I save the energy and waste the water?Or should I just shower in the cold? - Steven

[dmoonen 54]

Hey Steve I've dealt with this in many occasions and with many customers. The real issue is the heat loss in the lines your best off buying some thick pipe insulation and insulating all your hot water lines. Retrofitting and doing an recirculation loop is very costly to do in an preexisting home*, if it was a new home just being built it would make allot more sense.

In the end there's a couple ways:

[*]Check your plumbing and layout of your house and check if a reculation loop is possible if so ask for a quote and see if its an reasonable cost

[*]Insulate all your lines! Even if you had a recirculation loop you'd loose allot of heat in those lines causing your boiler to work harder costing your more $. A non insulated pipe is the same thing as an rad it would just heat the area around it. Ironically we use just bear steel pipes as heaters for farms and green houses.

[*] In Europe they have an small on demand DHW below each sink and shower for this exact reason to save water. In North America its not really pushed just due to the energy costs and the natural resources we have. There are larger on demand units that take over a standard tank and only works when there is flow (using water). I actually like these units just due to the fact that you have almost no heat loss on the heating unit itself, on an normal tank sitting at 80 deg c there's allot of heat loss even if the unit is not being used.

[*] Upgrade your boiler! Check its efficiency, newer tanks now a days get between 80-97% efficiency which also gives you an option to go with a smaller volume tank.

[*]Install water saver taps and adapters. You'll laugh but its true and it works, changed over full resorts and a couple social housing buildings and their numbers don't lie.

That's the basics on what I tell people and what I know from personal experience teaching and working in the heating and cooling field.

First make it more efficient then add the toys

Edited August 11, 2013 by dmoonen

[lebikerboy 96]

We've had a Bosch Tankless system for six years and wouldnever go back to a standard hot water tank...

[scwmcan 0]

Collect the water that you can when waiting for the water to get hot ( at sinks anyway). Use it for watering houseplants and drinking water instead of going down the drain. We have an instant hot water heater as well, I don't think a hot water recirculation system would work well with these. The systems themselves seem wasteful somehow too.

[TO Ed 9]

I have a friend in France who collects the water and uses it to flush the toilet. Just pouring water directly into the toilet works surprisingly well. He also practices the "if its yellow let it mellow, if its brown flush it down". We do this and have found our water bill reduced by 50%.If you do a total mass and energy balance on your recirculating system you will also need to include the removal of all of this extra heat in the summer using your air conditioning system. This will result in even more wasted energy. A better solution would be a small point of use electric hot water tank although space may be an issue.I'm not sold on these tankless water heaters. They are expensive and don't save nearly as much money as promised. In the summer we spend $10 a month for natural gas for all the hot water we use. This would include any heat loss. So the savings quoted by the tankless manufacturers are bold faced lies in my humble opinion. If I had to estimate the cost of our heat losses of our hot water tank I would say it has to be less than a dollar a month. I base this on the knowledge that the tank reheats the water about once a day if we are away. However when we are home and using water the tank heats the water about a dozen times a day. If we are away for more than a few days we turn the tank control off so even less heat is lost.

[Alex 21]

The heat lost from pipes as they cool enters the living areas for the most part, during the winter a welcome addition to the room temperature and most of the energy lost from your water heating is balanced by (marginally) less space heating needed. This time of year the heat is not so welcome, and if you use AC the loss is multiplied. A circulating system would be much less efficient as you're losing heat at the maximum rate continuously, not just until the pipes have cooled. Also the circulating pump requires some power.Remember the first principle: Reduce! Makes no sense to send perfectly good items to the landfill and spend thousands in order to save $10 a year.Sinks and showers can feed into a grey water collection system for watering duty with good effect. Some care needs to be taken WRT the cleaners and chemicals you use. This care should be taken anyway, regardless of whether it's your backyard or the world you're dumping into.

[SmartieParts 12]

Thanks everyone! Good points. Some counters:

Hey Steve I've dealt with this in many occasions and with many customers. The real issue is the heat loss in the lines your best off buying some thick pipe insulation and insulating all your hot water lines.

a good friend of mine runs a medium sized mechanical contracting (plumbing) firm. That was my first question - insulating. He told me it just doesn't help enough to be worth it for Pex pipe. Plus, I can only do the exposed sections, which is really just a couple of feet in the utility room and the small sections under the sinks

Retrofitting and doing an recirculation loop is very costly to do in an preexisting home*, if it was a new home just being built it would make allot more sense.

You put a * so I think you forgot to add a footnote? Anyway, a re-circulating system is simple and inexpensive as it doesn't require a return line. A circulating (no "re") is expensive for a retrofit. A re-circ is both more and less efficient than a circ. A circ has a 2nd hot water line so you have double the heatloss. A re-circ doesn't, but (and its a big "but"), it works by pumping the not-quite-hot water into the cold water line. This means you marginally heat up your cold water. So when you want cold... you have to run the water that much longer. Everything always has its pros and cons

In Europe they have an small on demand DHW below each sink and shower for this exact reason to save water.

This was my other consideration, until I read a lot of horror stories about them breaking down and leaking because they don't built them to the same standards as full-sized. Anecdotally, they need to be replaced every couple of years. As well, there's no mechanism to handle the break, so damage from the water leakage can be significant. If a full-size goes (in a modern home anyway), there are mechanisms in place to direct the water to a drain. I'll continue to look at it though.

Upgrade your boiler! Check its efficiency, newer tanks now a days get between 80-97% efficiency which also gives you an option to go with a smaller volume tank.

Pretty new home, so its a pretty new hot water heater. I doubt it is particularly efficient compared to others on the market (afterall, builders go for cheap, not good) but its going to be better than any older one. I'll get its life out of it, and then replace it with an on-demand when the time comes.

Install water saver taps and adapters. You'll laugh but its true and it works, changed over full resorts and a couple social housing buildings and their numbers don't lie.

I wouldn't laugh at all! Again, as its a newer home, code dictates they all be low-flow (1.8GPM or less. 2.5 for the shower).

We've had a Bosch Tankless system for six years and wouldnever go back to a standard hot water tank...

That's all I would ever consider if I were buying a new system. And will when this one dies. More efficient is a great reason... performance is another... one they shout about less in their marketing (but which I find important) is that they are physically much smaller and, consequently, take up much less space in the landfill at end of life (its almost entirely recyclable anyway)

Collect the water that you can when waiting for the water to get hot ( at sinks anyway). Use it for watering houseplants and drinking water instead of going down the drain.

Fantastic advice, but we're talking about a lot more water than the plants need. Still, every little bit counts and I really should be doing this. Ideally it would be neat if there was some way ALL the water that went down the drain could be filtered and used automatically for the lawn. But that's not going to happen.

I have a friend in France who collects the water and uses it to flush the toilet. Just pouring water directly into the toilet works surprisingly well. He also practices the "if its yellow let it mellow, if its brown flush it down". We do this and have found our water bill reduced by 50%.

I fear that's not possible (the 50% bit). Its a fact that the internal use of our water is fractional compared to external use (lawns). its not even close. A flush of a toilet uses 6 litres. It would take 167 flushes to account for 1000 liters, which costs only 35 cents. That's a lot of mellowing to reduce our bill any noticeable amount. Mind you, as I said before, the financial cost isn't my primary concern. I think we ALL need to factor other costs into our equations and stop looking at things just as dollars. Still, mold growth is another problem. We actually practice the "yellow let it mellow" too... but I think we're not going to as we have obvious black mold in the toilet and that can't be good. That requires more frequent use of bleach products, and that has its own concerns. Actually I didn't know what it was at first, but the rate that it grows and the organic patterns it produces are unmistakeable now. A little Googling showed us that its a common problem. Urine contains sugars and the mold growth is a result of that sitting. Various minerals in the water can result in black mold in one toilet and less-noticeable mold in another... but its likely there in all cases. I'm thinking its probably not the most healthy practice, and my family is going to weight the pros and cons and make a decision on that one soon. You may want to think about it as well and do your own research.

If you do a total mass and energy balance on your recirculating system you will also need to include the removal of all of this extra heat in the summer using your air conditioning system. This will result in even more wasted energy.

I hadn't thought about the space heating effect. I suspect it is minimal, but yes... part of the equation to be sure.

Remember the first principle: Reduce! Makes no sense to send perfectly good items to the landfill and spend thousands in order to save $10 a year.

You seem to be making two points, not necessarily congruent. The first ("Reduce") is a consumption principle and (should) have absolutely nothing to do with money. The second is a purely financial consideration, which is not what I'm really concerned about in all this. Going off on a tangent here... I'd like to see all decisions that we make - as individuals and as a society - use "new math". If buying a widget for $1000 saves $10 a year it obviously is the wrong decision, right? Only if that's the extent of the calculation. But if this example is talking about water, which is $0.35/1000L (here), then that means we saved 28571L that year! Sure, that saved ME $10... but that's only because our government assigns a ridiculously low dollar value to something that's obviously far more important than that number would imply. The water itself has an intrinsic value that no $ can be assigned.Anyway, thanks again for your responses. I think I'm going to take a closer look at under-counter (point of use) water heaters. I've read arguments against them, but perhaps that can be overcome simply enough. I also just had an idea Maybe it wouldn't be too difficult to install a temperature sensor at the most common problem points (the kitchen sink and our shower) so that the water is simply recirculated while it is being heated and in demand, and not at any other time. That means nothing would come out of the tap for the minute it would otherwise be heating. I don't think that system would be popular (it doesn't solve the annoyance factor of having to wait) but it would certainly stop the waste and wouldn't have the downsides, that you guys thoroughly examined, with the existing option! - Steven

[Overkll 0]

If you are watering your lawn then this whole discussion is moot. There is grey water collection (from sinks)... it's easily done pre-construction and is used for LEED certification. I'm sure a retro-fit would be pricey (maybe?). But the point above makes the discussion irrelevant.C'mon, how can you really worry about 5L of water if you already choose to live in a 'rather large' house. Seems a bit silly to me. Penny wise, pound foolish.JMHOKerry

[MikeT 747]

Don't water the lawn, we don't. Let it die in the summer and think about doing some xeriscaping to match the biogeoclimatic zone that you are located in.We hand water about 6 plants every other day and that's it. The nuisance of no hot water upon start up probably indicates bad plumbing design, specifically, poor tank location. In our house, we have two HW tanks, each near the showers and laundry room, so the "hot water delay" is maybe 5 seconds. It's not the best home either but electric hot water heating costs are OK...

[SmartieParts 12]

If you are watering your lawn then this whole discussion is moot. There is grey water collection (from sinks)... it's easily done pre-construction and is used for LEED certification. I'm sure a retro-fit would be pricey (maybe?). But the point above makes the discussion irrelevant.C'mon, how can you really worry about 5L of water if you already choose to live in a 'rather large' house. Seems a bit silly to me. Penny wise, pound foolish.JMHOKerry

You do realize what the H in JMHO means, right?Those ignorant to geography need not judge. And as I acknowledged about my house, that's a different discussion.Really your whole "contribution" to this thread has me saying, "thanks.. and bye". It was meant as a serious discussion that you've now trivialized. And from a "H" moderator.See yah.

[TO Ed 9]

There should be no sugar (glucose) in urine, unless you have diabetes. If you suspect sugar you may want to see your doctor. We have never seen black mold in our toilet. However, you are correct in saying that more frequent cleaning is needed. We use Vim.I am looking at my last water bill. From March 11 to July 15 (126 days) we (two adults) used 14.00 cubic meters of water @2.8567 /m3. Total cost of $40.00 for water and sewer. Our costs are consistent thoroughout the year. We don't water our lawn, however, it is usually green all summer (Toronto). The secret to a green lawn here is keeping the grass long so the roots are deep. We set our mower to the highest setting and mow infrequently.

[TO Ed 9]

I just saw your response "those ignorant of geography need not judge". Hopefully you won't see my comments as judgmental.Last time I drove through the Okanagan valley I was struck by how arid the South end was, with cactus and sagebrush the predominant plant species. So trying to grow grass would be challenging. My wife has been suggesting to me that we should get rid of our grass in favour of a rock garden. We have seen some lovely rock gardens in our neighborhood. I have also seen artificial grass in front of homes in Florida. It is so realistic I didn't recognize it at first. I am sure that I have seen many artificial lawns and assumed they were real.Just some suggestions. Not judging.

[fordnut71 1]

there is a tube called power pipe. its a heat exchanger on the down pipe. as your cold water supply goes into the tank its pre heated as it enters the hot water tank.

put this with a instant hot water maker an you would have endless hot water supply. maybe looking into solar hot water tank. you can get these systems coupled all together to reduce costs in the long run.

http://www.renewability.com/power_pipe/index.html