has anybody compiled a list of rapid return energy saving measures?

[chrisvillar]

I am very interested in conservation, green living, living independent of the grid, etc. Has anybody compiled a list of simple energy saving measures that have a reasonable return on investment (

[Steve Spence]

Replace lighting with CF's Where appropriate. (all our lighting is CF)

Place phantom loads (TV, Microwave, Transformers) on switched power strips.

insulate doors and windows

add rain rarrels to downspouts for lawn and garden irrigation.

low flow faucets, shower heads, and toilets.

high efficiency appliances

Steve Spence Dir., Green Trust

[e-mail] wrote:

[Info]

Hot Water Savings

The key to hot water savings... eliminate the waiting.

Every second a person spends waiting for hot water at their faucet / shower, your water heater is taking in "cold" city water. In addition to the lighting energy used while the person stands there waiting. A family of four waiting 1 minute for hot water spends around 97.3 hours every year "waiting". (Four people waiting 4 times per day, 365 days in a year, divided by 60 for total hrs) Include a lifestyle fudge factor and reduce it to 72 hours of "very cold" city water filling up your water heater needlessly. Let's pause for a moment and imagine having to stand and watch a faucet waste water down the drain for 72 hrs. . . . Or consider a home which waits only 30 seconds.... that's still 36 hours of watching water run down the drain.

Install a RedyTemp Hot Water Recirculator, no dedicated return line required, idiot proof 10 minute "self-install".

Behind the timer is a standard 3-prong wall outlet. Simply replace the timer with "The Clapper" set the clapper to the "away" mode. Now when the clapper hear's someone in the bathroom it will auto start the circulation process.

Or consider using the RedyTemp in the On-Demand mode using a wireless push-button. Simply replace the timer with a "wireless outlet control" similar to those used by the elderly when they don't want to get up to turn on/off lamps. Press the wireless remote control from anywhere in your house (range 100-150ft) for no-wait hot water throughout your home.

Return on investment estimated at two years for a family of four which waits an average of one minute for hot water.

Install a tankless water heater for "endless" hot water and a RedyTemp for "no-wait" hot water.

[Edwin Pawlowski]

Crock of crap, really. While waiting for the hot water for the shower, I use the cooler water to brush my teeth or rinse my eyeglasses. No wasted time, no wasted water. Same wit dishes. A quick rinse is OK for the cooler water too.

[chrisvillar]

The only time I wait for hot water is in the morning before I shave. And I'm not really waiting, the water is running while I'm taking a leak. And maybe I've wasted 4 gallons? At $0.005 per gallon, that's $7.30 per year in wasted water. What's my return on investment now? After the shave, the hot water is 4' away from the shower head. By the time I turn on the shower and walk around the curtain (2 seconds) to get in, it is already up to temp. So that is zero wait time for me and maybe 4 gallons of wasted water.

When I give my infant daughter a bath, I turn the water all the way to hot and rinse the tub with the cold water from the pipe. I'm done rinsing before the hot water get there but I close the stopper anyway. When the hot water finally gets to the tap, I let it run all the way hot for a few seconds to get the tub temp right and then turn the temp down and continue to fill. Then I put my daughter in. So no wasted water at all and no wasted time for my daugther's bath.

Let's say I have two school aged kids. Most likely, they are taking showers back to back so the second child starts the water with the pipes already "hot". Same situation if two adults are getting ready for a work day in a separate bathroom. So suddenly a family of 4 with

4 waits per person per day for a total of 16 "waits" is reduced to 2 "waits".

Actually I love the idea of a tankless water heater but for three very different reasons. There is basically zero savings from reduced water useage. It is calculable but negligible as I've described above. The three great things will be 1) the reduced energy bill because I'm not continually keeping 40 gallons of water hot (and stupidly using that 40 gallons to heat my Texas house or garage), 2) the reduced space requirements, and 3) the luxury of instant hot water if it can be installed close to the tap as a result of #2. What I'd like to do when I build my house is install the tankless water heater in a closet right next to the master bath. The kids and guests will have to rough it like we used to do in the old days and wait a minute for hot water. I'm the one paying the bills after all :)

[trader4]

"There is basically zero savings from reduced water useage. It is calculable but negligible as I've described above. "

The issue isn't the cost of the water that's wasted, but rather the cost of heating the hot water that has to run from the water heater to the faucet every time you first need hot water. It takes quite a few gallons of water to flush out the cold water in the pipes and get the pipes warm. The longer the pipe run, the more energy that is wasted. A tankless unit saves that energy loss and it can be considerable.

[Nick Hull]

If it takes 'quite a few gallons' to flush out the cold water then you are using pipes too big, and probably metal pipes as well. If you use

1/2" plastic pipe there is little cold water to flush out and little thermal mass to heat.

[BobG]

Anyone ever put a neon light across the hot water heater element to actually observe when the hot water heater was operating? Whats the duty cycle with NO HOT WATER USE during the day? Is this calculatable given an R rating for the hw heater, and air and water temp?

[Derek Broughton]

That's exactly what I was thinking as I waited for two gallons of cold water to flush through my pipes this morning. They're plastic, but embedded in concrete (and I don't think they're insulated) and 3/4" - obviously, 1/2" pipe would have wasted less than half the hot water.

[chrisvillar]

I hate to split hairs but the energy savings from the tankless is that you don't keep 40 gallons of water hot and on standby. The energy used to fill flush the pipe is the same with either, unless you get the tankless close to the tap. Maybe that is what you are talking about. In that case, you would be right and I covered that advantage in the last paragraph of my previous post.

[chrisvillar]

According to my calculations, a 1/2" I.D. pipe holds one gallon per 98 linear feet of pipe. So I was way off in my guess that I waste 4 gallons of water in the morning. The run from my water heater to the bathroom is no more than 40'. So I am wasting about 40% of one gallon.

Check my calcs:

1 gallon = 231 cubic inches

cross sectional area of a 1/2" I.D. pipe = pi * r^2 = 3.14 * 0.25 *

0.25 = 0.19625 square inches

231 cubic inches / 0.19625 square inches = 1177 inches = 98 feet

A honkin' 1" pipe would be one gallon per 24.5'. Even with that huge a pipe, I'd waste less than half the volume of water I guessed in my post yesterday.

[Dave Hinz]

1/2" plastic isn't code around here for source lines unless that changed very recently, and 1/2" pipe for any length gives you crap for flow rate. I'll stay with my 3/4" copper, thank you.

[chrisvillar]

I don't know if your heater is elctric or gas. If it's gas, you can hear the burner kick on and off. I'm guessing you are talking about electric. In that case, they make such a thing as a Kill-a-watt meter. It's only made for 120V but it plugs into the wall between the outlet and the appliance and measures actual energy usage. I know the same sort of devices are made for 240V but they are probably all for industrial applications ($$$). I used one once to monitor the energy useage of a central AC unit. I was running an experiment on cooling the air around the outdoor unit with evaporative cooling while the unit was running. It made a significant difference in the energy useage. I was using those misters you can buy at Home Depot for cooling paios. The problem is that you need a really clean water source or the misters get fouled and you would eventually end up with scale build up on the AC coils. Not good.

[chrisvillar]

3/4" I.D. is 43.5' per gallon.

[nicksanspam]

It's estimatable. A 25 ft^2 50 gallon tank with R10 insulation and 110 F water in a 70 F room needs (110-70)50ft^2/R10 = 200 Btu/h, ie 59 watts, ie a 100x59/4500 = 1.3% duty cycle with a 4500 watt heater.

Nick

[nicksanspam]

CPVC may be, for hot water.

The Hazen-Williams equation says L' of d" smooth pipe with a G gpm flow has a P = 0.0004227LG^1.852d^-4.871 psi pressure loss. L = 50' and P = 40 psi makes G = 9.5 gpm for d = 1/2" pipe.

Nick

[Derek Broughton]

What's that in English? I _think_ it means I have to have over 40psi in my pipes to begin. Most well systems run about 40psi.

[Dave Hinz]

Maybe. But, I really, really don't like off-tastes in my water. I even have copper for my well piping rather than the (cheaper) plastic option.

OK, and the "personal observeations" equations show that I'm happy with my flow with 3/4" pipes until they go into the walls, the water is hot in a few seconds, and that in houses with bad flow, it's invariably 1/2" pipe. Since there's only one gallon of volume in 45' of 3/4" pipe, what problem am I really solving by choking off my flow?

[trader4]

"If it takes 'quite a few gallons' to flush out the cold water then you

are using pipes too big, and probably metal pipes as well. "

Oh yeah? And how big is your house. In a two story 4000 sq ft house, you can easily have a long run from the water heater to an upstairs bathroom.

[nicksanspam]

"Choking your flow" to 9.5 gpm can save a little non-recurring cost and recurring time and water and energy.

Nick