Monday, February 18, 2008

Saving Water

The tendinitis in my shoulder is keeping me from much progress on the house, or from doing a lot of things like driving without some pain and further damage involved. So I've been researching various things for the house on the web. There are so many great ways to save energy and water that it's all kind of dizzying. The cats are happier when I'm sitting at the computer than making construction noise, so they like the research, too.

Given that California frequently has droughts, and by nature has dry summers, saving water makes a lot of sense. Of course, what we could save is a drop in the bucket (hah!) compared with gets used for commercial and agricultural uses. And agricultural uses are a drop in the bucket compared with what gets used for raising and processing meat, which is particularly water-intensive (especially when 143 million pounds of it has to be disposed of -- ugh!). But it still makes sense to save what we can.

Some ways of saving water are too simple to pass up, like rain barrels (unless you live in Colorado, where collecting rainwater is illegal.) For less than $50 you can get a food-grade barrel and some fittings, and collect 55 gallons of rainwater, perfect for watering plants and gardens. We've got 7 downspouts around the house, plus one from the roof of the carport, so we could easily collect more water than we could use (at least until we plant a garden again or actually take care of the plants in the yard.) I'm envisioning a system of two or three barrels, with pipes draining them leading to a spigot in the back of the house near the current hose spigot. It's low enough that gravity would give it a pretty decent flow, and be near the backyard where most of our watering needs are.

At the other end of the complexity scale is adding a graywater system to collect the water from bathroom sinks, showers, and the laundry, then using that water to irrigate or for flushing toilets. It would involve not only a storage tank with a way to deal with overflow, but a pump to drive the system, and a way of using EBMUD water if the storage tank is empty. It would basically be a second DWV system, plus parts of a second water supply system to go to the toilets. A lot of work for limited payback, and it's not legal in all areas.

Another fairly simple way is a hot water recirculation system. You've doubtless left the shower or a sink running to let the water get warm, and all that nice, drinkable water just goes down the drain. Hot water recirculation systems get water from the hot side, and if it's not warm enough yet, push it back down the cold side (a more complicated but more efficient variation uses a separate return line.) Some systems keep hot water circulating all the time, so it's available "instantly". That would waste energy keeping water hot whether you're using it or not, not to mention add unnecessary wear and tear to the water heater. And without a dedicated hot water return, it would make all your cold water lukewarm. Other systems like the RedyTemp or the Metlund D'MAND are timer, motion or demand-activated.

Our hot water use doesn't follow any set schedule, so we'd go for a demand-activated system: you push a button, wait a couple minutes, and voilĂ , there's hot water a couple of feet down the pipe instead of waiting for the water to flow, the tankless heater to kick in, and then for the cold water to be flushed from the system. Those systems and others are very easy retrofits if you've got an outlet near the fixture furthest from the water heater. Since I had a hot water recirculation system in mind, I didn't go as far as plumbing a dedicated return line, but I did stick a GFCI outlet in the vanity in the new bathroom.

Now the only problem is figuring out which is the right system for us. Tankless water heater manufacturers will reduce the warranty if you use the wrong recirculation system, because very high flow rates can erode pipes and fittings and put additional wear and tear on a water heater. Anybody out there in readerland have personal experience with one of these systems, with or without a tankless heater?

10 comments:

Fred said...

Recirculating gray water into other uses makes a lot of sense. Here in Balto. Co. MD we're spoiled in that we pay very little for water (its included primarily in property taxes)... but, being spoiled leads people to not conserve. We recently had a pretty big spike in gas and electric rates (+70%) It was quite the fiasco, but has us all conserving now.

Anyhow, its important to be good stewards of the resources we've been given - its great that all this information is available to us right at our fingertips.

Fred
One Project Closer

Gene said...

Water isn't that expensive here, either (or at least it doesn't seem it with the small amount we use). But we've been through too many drought years in California to not take some steps to conserve in general.

Sandy said...

Loved the pictures of the cats! Why would it be illegal to collect rainwater? I've never heard of such a thing! My grandmother (in Tennessee) used to have rain barrels. She used that rainwater for everything! I can remember when she washed my hair in it, it made my hair so soft. (that was 54 years ago!)

Gene said...

It's because much of the west has more water needs than it has water. In Colorado, water is considered a 'public resource' (i.e., something for the government to control and sell). By collecting rainwater, you're keeping it from going downstream to someone else who has rights to the water. Water rights in the west are complicated, to say the least. An interesting book on water in the west is Cadillac Desert.

John said...

When we bought our house in Pasadena, we retro-fitted for a tankless and recirc (timer) system, which works fine. The warranty of the tankless went from 10 to 3 years, but I figure that that's mostly blah-blah anyway.
Wish I could have done a grey-recyc system, but not allowed here.

Gene said...

I haven't found out yet if graywater systems are legal here in Oakland or not, though at the very least I could use it for watering. But regardless, that'll be further down the line.

Out of curiosity, what make and model of tankless and recirc do you have, John?

John said...

HI Gene,

I'm flying out the door, but Monday or Tuesday I'll give you teh specs, and also the conversation I had with the tech people about the recirc system and why the waarnty is shortened.

Best

John

John said...

OK, 3 weeks later.

Takagi T-K3 and Grundfoss recirc pump.

We have 3 bathrooms (2 showers, 1 tub combo) washer and dishwasher, 2 kitchen sinks. (I know, I know, but I designed the kitchen to be usable by up to 4 cooks and 4 helpers and this works.) I kitchen sink and 1 bath are currently on the recirc, but there's enough capacity to add the other sink and both baths as we progress.

I talked to the folks at Takagi, and long story short, the warranty is shortened because the heater isn't designed to run more than a total of a few hours/day, and the recirc pump adds time to the hours used, right? Further, the pump has to be big enough to carry away the hot water, because otherwise the firebox would overheat, if there wasn't enough flow. And there are more considerations, but if you call the MFR of your tankless, they'll tell you how big a recirc pump you need, and it will seem t o be too big, but it'll be right.
Don't forget an expansion tank.

We use a clock timer, and it's set for 5-7:30 AM and 4 to 8:30 PM. Plus we can always turn it on manually, but in practice we don't, we just wait for water the rare times we aren't within the time zone. But if we were finding ourselves waiting too often, we would change the timer.

If you use a switch, make sure it turns off after a set amount of time. If you use 2 or more switches, use a relay to isolate them from each other.

Any questions, let me know.

Best

John

Gene said...

Thanks for the update. We've got a TK-3 as well. If we go with a recirc pump, it'd be on demand, not timer-based. We have 2 baths, a smaller kitchen, and a laundry for our hot water needs, but it's rare that we use it at a set time every day. My wife is up early M, W, Th, works at home Tu, and has F off; she's up earlier on some Sundays and I'm up earlier on others. In any event, it'll have to wait a bit. I'm headed for Mexico next week to take the youth group from our church on a mission trip to build a house. I'll wave when we go past Pasadena :-)

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