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 (<5 years). I'd
like to start spending a couple hundred dollars a month to upgrade my
house. Getting my wife's approval, and to really justify it to myself,
I need to have confidence that it is a good investment. Anybody done
any work on this?
I have a 1600 sq. ft. house in central Texas. Standard 2x4
construction. Gas heat, waterheat, and stove. Already switching to
compact flouresents as the incandesents burn out. No programmable
thermostat but that is because my wife is at home with my daughter.
I can get info for our water, electricity, and gas useage if anybody
wants to lend a hand or advise.
What would really be fun is implement some improvments that will save
money in the long run with minimal impact on our lifestyle. My wife
will be a reluctant partner in this effort so minimal impact on our
lifestyle will be essential.
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
Dir., Green Trust
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
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.
On Fri, 17 Dec 2004 17:21:32 GMT, Steve Spence
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.
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
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 :)
"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.
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.
Free men own guns, slaves don\'t
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?
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.
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.
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.
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
On 17 Aug 2005 12:11:59 -0400, email@example.com
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?
On 17 Aug 2005 14:48:50 -0400, firstname.lastname@example.org
Let's try this again. From my water heater to my primary point of hot
water usage, there is 14 feet of pipe. This is not coincidence; I put
the water heater directly under the shower and the washing machine for
that reason. Now, if it takes 45 feet of 3/4" pipe to make one gallon
of volume (someone else's number posted here, which I haven't checked
myself), that means I have just about 1/3 of a gallon of water in those
pipes. Even to the other end of the house, 35' away, there's only a
gallon of water in the pipe between the heater and the faucet. I could
calculate the thermal mass of the copper pipe, I suppose, but I don't
see it making a lot of difference in practical terms.
Yes, you get _decent_ flow with 1/2" pipe. I get _better_ flow with my
3/4" pipe, and given that I never use straight hot water, running a
gallon of cooler water through the hot pipes isn't a loss anyway.
To me, the extra 20 bucks for pipe when I built the house is worth not
having to worry about what else is happening in the house when I want to
take a shower.
You're both assuming that the piping itself is the predominent pressure
drop. In almost all cases, this just isn't so. The straight length of
piping isn't the 'bottleneck'. Keep in mind that an 'average' 90 degree
elbow is about the same flow resistance as a straight length of pipe that is
30 'pipe diameters' long. And a typical globe valve is about the same as
140 'pipe diameters'. So a 14 foot run of 1/2" pipe, with just five
'elbows' and one globe valve under the sink is really equivalent to 14' +
(5*30 + 140)*0.5/12 = 26 feet. If it is 3/4" pipe, then the same number of
elbows and globe valve is equivalent to 14' + (5*30+140)*0.75/12 = 32 feet
of straight pipe.
But in both cases, the majority of the pressure drop is right in the
faucet/spout. If you figure out the pressure drops through the various
portions of a typical lavatory sink run with a flow of about 1.5 gpm and 40
psi source, then replace the piping with a larger 3/4" pipe, the actual flow
change is very little. For a bathroom sink with a flow of 1.5 gpm, an
equivalent 26 ft of 1/2 pipe only has a pressure drop of about 0.7 psi using
nick's formula (Crane TP-410 shows a slightly different number, but pretty
close). The rest of the pressure drop is right in the faucet. Even if you
eliminated the piping completely, the flow would only increase by a factor
of 1.008 (less than 1%).
About the only place 3/4 makes a big difference over 1/2 is if it is feeding
several fixtures that may be used at the same time (e.g. the shower and the
toilet at the same time is a classic), or when the total flow is not
dominated by the faucet (those used to fill a tub comes to mind). So it
does make some sense to run a larger pipe to the general area of the
bathroom and to the fill spout on a large tub, then split off smaller pipe
to individual fixtures.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.