Saving on electricity?

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  • Thu, Mar 24, 2016 - 04:42pm

    #1

    gnltabor

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    Saving on electricity?

Electricity is the foundation of modern living.  We use it to heat, cook, light, and power devices such as phones, computers, and TV’s, toasters, coffee pots, etc.  Some people are powering yard equipment like lawn mowers, weed whackers, landscape lighting, decorative fountains, hot tubs, swimming pools, and even PEV automobiles today with electricity.  Now some of you may be using natural gas to cook, run your clothes dryer, water heater, and furnace, but even these devices today usually have electronic ignition, electric powered blowers, and electrically powered circuit boards.  When considering use of Solar PV panels to generate your electricity, it’s best to reduce your electrical consumption by installing more energy efficient appliances and lighting beforehand to reduce the amount of PV capacity you’ll need to install.  This reduces the capital outlay for your PV array and associated racking, inverters, breakers, etc.

The U.S. Energy Information Administration (EIA) reports that the average U.S. home uses about 10,000 kwh of electricity annually, with the state of Hawaii representing the low end at 6,000 kwh/yr and Louisiana on the high end with 15,500 kwh/yr.  While Hawaii’s low number partially reflects their high price of electricity and balmy weather, it also reflects their high adoption of solar PV to keep their costs down, meaning it’s not the actual average electrical consumption, but rather the average supplied from the utilities.

One of the fastest paybacks on energy efficiency is a hot water heater blanket.  This is true whether you have an electric or natural gas hot water tank.  Spending $15.00 or less on a hot water blanket will cut your energy consumption for heating water in half without changing the temperature at the tap and will achieve a payback in a few months.  Of course, dialing back the temp to around 120 degrees will prevent scalding and save money too.  Also, remember to set back the temp while away for extended periods of time such as when visiting family over the holidays or going on vacation.

Lighting typically accounts for 25% of the total electrical consumption of a home when using traditional incandescent and fluorescent tube light fixtures.  While the bulbs are more expensive, LED’s and CFL’s will drastically cut your electrical consumption versus traditional incandescent bulbs, and also have life expectancies that are 10-25x longer than classic incandescent bulbs.  One exception to this rule is when a fixture will frequently be turned on and off for periods of short durations like in a closet or powder room.  CFL’s do not hold up well under frequent, short duration usage, and electricity savings will not quickly pay for the higher costs of LED bulbs. 

A standard LED bulb with 60 watt equivalent incandescent light output will only use 9 watts while a CFL will use 13 watts.  That represents electrical consumption reductions of 85% and 78% respectively over incandescent bulbs.  While dimmer bulbs are not yet justified due to significantly higher bulb costs and a need to replace the dimmer mechanism, most other fixtures, including flood lights, can accept LED bulbs today.  3-way lamps also do not have an equivalent alternative LED or CFL bulb today.  If you can’t afford to replace all of your bulbs immediately, replace bulbs in fixtures with the highest hours of usage.  For instance, replace exterior lamp bulbs with LED’s as those typically run all night, every night.  If you have children who leave lights on in a recreation room as I do, 10 incandescent flood lamp bulbs will consume  650 watts, while LED equivalents will use only 90 watts.  If you leave certain fixtures on at night for safety or comfort, they will also be good candidates for replacement.  Likewise for lighting in frequently occupied bedrooms dining rooms, kitchens, and family rooms.  Save the old incandescents to replace burned out bulbs in low use fixtures such as closets, guest bedrooms, storage rooms, furnace rooms, garage door openers, etc.  Ballast type tube flourescent fixtures can also be replaced with LED alternatives, dropping power consumption to 40 watts for a 300 watt incandescent equivalent output.  Recessed Flourescent tube lights in kitchens are good candidates for complete fixture replacement if you have the money for such an investment.

I had a whole house audit done last year to look for other opportunities to improve the energy efficiency in my home.  There’s much to tell there, but for now, let me point out one item the audit identified for me…  My son had his iphone charger plugged into the bedroom wall with the charging cord lying on the floor.  The FLIR camera the auditor was using lit up that cube like a christmas tree!  Make sure you’re not leaving charging devices plugged into sockets when not being used, and use power strips to fully turn off or otherwise unplug other devices that are not actively being used such as computers, printers, copy machines, paper shredders, game consoles, stereos, dvd players, and older style TV’s; anything that is not energy star rated.  Here’s a website showing typical power consumption of a range of electrical appliances.  If you think you’re saving money by using an ancient refrigerator or freezer in your basement or garage because it allows you to stock up on sales, be careful… Check out this document from the Eugene Oregon Utility for typical energy consumption of a long list of electrically powered devices:  eweb.org/public/documents/Typical_res_Cost.pdf

If we assume $0.10/kwh and 2,500 kwh/yr for lighting, a 50% reduction in electricity consumption from switching your highest used lights to LED’s will save you $125.00/yr on your electric bill, more if your electrical rates are higher or you go beyond replacing 60% of your incandescent power consumption with LED/CFL alternatives .  In my personal experience, I had been using around 12,000 kwh/yr.  I swapped out all justifiable incandescent lights with LED’s and CFL’s and purchased a Nissan Leaf in 2013.  I drive the Leaf an average of 8,000 miles per year, while my annual electrical consumption is virtually unchanged.  If I’d bought a traditional gas powered 4-passenger sedan, I’m avoiding the purchase of somewhere between 250 and 350 gallons per year of gasoline.  Depending on the price of gasoline, I’m saving between $500 and $1,000/yr through frugal management of my electricity consumption coupled with driving an all-electric PEV.  Taking it one step further, I installed 6.6kw of grid tied solar panels on my roof last year and have virtually covered 100% of my annual electrical consumption.  While the payback may take 10 years to break even at current electric rates, I’m confident I’m running on renewable electricity, reducing greenhouse gases, and doing a small part to reduce our dependence on foreign oil.

 

  • Fri, Mar 25, 2016 - 02:14am

    #2

    David Huang

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    A couple thoughts

A few years ago I did go to an entirely off-grid electric system.  Prior to that I was most certainly all about finding ways to conserve, conserve, conserve!  Once I got my usage down to 100 KWH or less every month for a couple years I made the move to get a photovoltaic system to meet this usage.

One other thing I did with my water heater was to install an easy to access switch so I could just turn it off unless I wanted hot water.  I didn't really need to have piping hot water ready on demand 24/7.  I realize this wouldn't work as well with some people, but I found I mostly used it for a hot shower every other day.  I would be better off with a solar hot water system, but my home is really quite small.  I don't really have a good space for the size of storage tanks needed to make such a system work well.  Initially I had a 30 gallon tank.  This past winter in order to save even more electricity during the short cloudy days when my PV system is just barely enough I asked myself if I really needed 30 gallons.  I decided to change out my 20+ year old water heater with a 15 gallon one.  I was a bit concerned that my showers might get a bit cool toward the end, but there has been no change at all except that I'm now heating half of what I used to.

You noted the various energy vampires that always draw small (or large) amounts of power when plugged in.  I thought I'd add that anything with a remote control will be constantly drawing power unless you have on something like a power strip that you can turn off.  The remote sensing device has to be on 24/7 searching for that signal when you push a button on the remote.  Also, I discovered that some radios, even if they don't have a remote, will always draw power when plugged in, even when they are "off".  I ran into this with my first small off-grid PV system for my art studio.  It took me a while to discover what was drawing power.  Then a friend who working in the audio/video industry told me it was probably my radio, and it was.

I'll share one other oddball thing I did to save electricity that most don't really think of (or want to do).  My water comes from a well, with a well pump.  So for me using water means using electricity.  I went to using a sawdust composting toilet.  So instead of using gallons every time I flushed I've gone to using 2 quarts every week or so when I empty the bucket.  As a side bonus, I'm also recycling the nutrients rather than creating a waste stream, and I don't really have to worry about pumping out my septic tanks anymore either since they have so little real use.

  • Fri, Mar 25, 2016 - 11:59am

    #3

    roosterrancher

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    Phantom loads

We tend to put our cell phone chargers and such into a power strip so that we can turn the power off when we are not actively using them.  When we built our off grid home our equipment supplier suggested that we install a dedicated receptacle that would be controlled by a switch with a pilot light. As it is installed, half of the receptacle is hot and the  other half is controlled by the switch. From across the room we can see if the power is on by looking at the pilot light and we can turn it off easily with a switch. We don't have to crawl under the desk any more to turn off the power strip!

If you can lick heating and cooling it is surprising how little power it takes to live. Sounds like you are all over it David!

  • Fri, Mar 25, 2016 - 01:32pm

    #4

    David Huang

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    Heating and cooling

You're right Robshelper, heating and cooling can be big power draws too.  For those I heavily insulated and installed new windows and doors in my home.  That basically eliminated any cooling needs.  Prior to the insulation my home would roast in the sun on summer days even here in Michigan.  After the thick insulation it might get uncomfortably hot a few days a year, not enough to even worry about getting air conditioning.  The fun part is that the major insulation project cost about the same as central air conditioning might have, with no continuing energy costs.

For heating I am fortunate that I work at home so I was able to install a small wood stove and be around to tend it.  The propane furnace is now my back up heater, so I'm no longer using much electricity to run the blower motor.  When I buy firewood I get it from my next door neighbors as a way to support them and build community or social capital.

The dedicated receptacle with a switch that has a pilot light is a great idea.

  • Fri, Mar 25, 2016 - 01:57pm

    #5

    David Huang

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    Off grid electric space heating

Oh yeah, one other oddity I've found for heating my home.  There are times it makes the most sense to use electric space heaters!  This really did a number on my brain when I realized it.  I don't know if you do it, Robshelper, in your off grid home.  My PV solar system had to be designed to handle my needs around the winter solstice when the days here are short, cloudy, and snowy.  In the spring and fall when I still need heating the solar system is usually generating plenty more power than I need.  Since it's not connected to the grid where others could use the power the excess just goes to waste.  So now when there are nice full sun days during these seasons I will turn on electric space heaters to heat my home, thus using this power rather than wasting it.

I had gotten so used to always looking for ways to conserve electricity I hadn't at first realized things changed once my off grid system was set and in operation.  Now it's more about power management of what's available which can mean finding ways to use more in a productive manner.  For this reason I've also gotten an electric chainsaw, wood chipper, and weed whacker.  If I really mowed my lawn I'd get an electric lawn mower.  (I just use a scythe a couple times a year on the broad areas instead of mowing.)

  • Sun, Mar 27, 2016 - 01:38am

    #6

    gnltabor

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    WIndows & Passive Solar Heating

Good exchanges on heating and cooling.  I too began replacing windows last Fall, starting with our upstairs bedrooms.  As part of my energy audit, windows were identified as an opportunity for energy savings.  Our home was built in 1994, so the original builder grade windows were single hung, i.e. they only opened at the bottoms.  While they were double paned, they did not have any special insulating gas such as Argon between the panes, nor did they have any low-e glazing treatments.  To top it off, at over 20 years old, we were blowing seals (condensation between the panes of glass) and had weather stripping falling out of the windows when we opened and closed them, especially for south facing windows. 

Living at 7,000 ft elevation, the nights cool down quickly after the sun sets, but with windows that only opened on the bottom, heat was trapped in the upper half of the rooms during hot summer days.  Therefore, one of our objectives was to replace with double hung windows so we could open the tops to allow air to escape from higher in the rooms.  Double hung windows would also allow us to tilt them in for cleaning, an important consideration as the upper windows on the back of the house were 2.5 stories above grade.

After researching passive solar design recommendations, I learned that south facing windows should have a Solar Heat Gain Coefficient (SHGC) of at least 60 while East or West facing windows should have a SHGC of 25 or less to reflect heat.  All windows should have Low-e glazing treatments and a U-Factor of < .35.  A U-Factor can be converted to an R-Value by dividing 1 by the U-Factor.  For instance, a window with a U-Factor of .25 would have an R-Value of 4.   I researched various glass manufacturers and learned that Cardinal Glass offered a product called Low-E 180 for passive solar applications, which is exterior glass with a single Low E glazing that allowed 80% light transmittance.  Cardinal also offered a new inside treatment to what's known as the 4th surface with Indium that prevents infrared heat from escaping once it's entered the house and a light transmittance of 89%.  Combining Low-E 180 for the outside pane, I-89 for the inside pane, and filling the chamber with Argonne gas provided an SHGC of 62 and a U-Factor of .27, meeting the objectives for our south facing glass.  Using Low-E 272 (double glazed) glass on the front and side windows with I-89 and Argonne gave results similar to triple pane glass with a U-Factor of .25.  Cardinal had a plant in Colorado so the altitude pressure concerns were not going to be an issue.  Now the trick was to find a manufacturer who would use Cardinal glass and allow us to order different glass configurations for our south facing windows.  After calling the Cardinal factory, I learned that Milgard should be able to provide what we were looking for.  Once I had a quote, I found the costs weren't significantly higher than the lowest cost providers that didn't offer the same flexibility in glass configurations so we moved ahead.

Our new windows were installed in early October and the comfort level this winter has been noticeably better than with our old leaky windows, especially when it's windy.  While the change in heating costs have not been dramatically lowered yet, we still have 2/3rds of our windows to replace, but the improved comfort alone has made them worthwhile.  In addition, we look forward to being able to ventilate using the double hung features and save money on window cleaning now that we won't need to be on tall ladders to get to the upstairs windows. 

While we've more than doubled our R-Value for the new windows, we still use blinds and curtains to further insulate the windows at night.  Our plan is to replace the plantation style wooden blinds with honeycomb room darkening blinds upstairs which will add another 2+ to the R-Values of our bedroom windows.  Our cost for the 10 new windows was just over $600 each.  While we won't achieve a quick payback, we have contributed to reducing our energy consumption, overall comfort, and convenience.

 

  • Sun, Mar 27, 2016 - 02:06am

    #7

    roosterrancher

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    Pasive solar

What a great exchange!

In building our off grid passive solar house I was surprised at how effective the passive solar portion is. It really works well to heat our home. There are times when it can be too effective. We have louvers between our windows that can be raised and lowered, in the horizontal position the louvers cut out enough sun to stop the solar gain. Summer nights are cool where we live and an upstairs window left open will funnel the breeze through out the house. Close it up in the morning and it is cool all day. Closed cell spray foam through out the house, even under the concrete floor.

gnltabor and David Huang, nicely done.

  • Sun, Mar 27, 2016 - 04:38am

    #8

    gnltabor

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    Rocket mass heaters

Wood stoves can heat a living space while adding ambiance and provide a good alternative heating source during a power outage when electric or electronically ignited gas furnaces cannot run.  I've been studying rocket mass heaters as a super efficient wood burning heater option.  Rocket mass heaters are being used to heat homes, green houses, saunas, and bath houses.  Rocket mass heaters run best on well seasoned dry wood to produce the most efficient burn.

A rocket mass heater can be made with either a j-tube or batch box design for the burn chamber.  From my research, the batch box provides a larger fuel reservoir for longer burning.  A rocket mass heater differs from an ordinary wood stove by providing a large mass to absorb heat, releasing heat slowly from that mass for up to 24 hours after the actual burning of fuel has ended.  This is accomplished by running the combustion through an insulated combustion stack, through a bell, and out a  6" or 8" diameter horizontal pipe that is looped through a bench made out of cob to provide the heat absorbing mass, before exiting through a conventional vertical stove pipe.  The cob bench can be designed for seating, providing added utility.   Optimally tuned, a rocket mass heater offers a super efficient, clean burn with a smokeless exhaust that leaves the chimney at a relatively low temperature.  This form of wood burning device can be run daily for a season on little more than a cord of wood, saving money, time and wood storage space. 

If you're not familiar with rocket mass heaters, do a search on youtube for how to instruction and examples of rocket mass heaters.  Check out http://www.rocketstoves.com for a how-to instruction manual and further insights into rocket mass heaters.

  • Sun, Mar 27, 2016 - 11:41pm

    #9

    David Huang

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    I envy you, robshelper, for

I envy you, robshelper, for having a passive solar house.  I decided to work with what I had, which unfortunately was an old mobile home oriented it just about the worst way possible for solar gain.  Gnltabor, I really wanted to build a rocket mass stove for my home too, but again that mobile home thing is stopping that.  I just don't see the floor being able to support the tons of weight.

However, the current large homestead project I've started involves building a greenhouse off the south side of a small pole barn, to serve as both a greenhouse and provide some solar heating to the barn.  It's also a building where I have a solid floor so I may just build a rocket mass stove out there sometime.  🙂

Thanks for all the info on windows too.  I feel kinda silly for never realizing a big reason for double hung windows would be to let out hot air from the top.

  • Mon, Mar 28, 2016 - 03:08am

    #10
    mntnhousepermi

    mntnhousepermi

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    frugal heat retention, electric usages

We heat entirely from wood, everyone in this neighborhood does, anything else is too expensive. My house is more comfortable than some due to its layout, it is a story and a half house and heat easily leaves the great room to the upstairs. The difficult houses around here are the ones with hallways with 90' turns from the room with the woodstove, the heat doesnt circulate to the further rooms for those, and my friends use an electric space heater judiciously in the farthest bedroom. The one item that helped this house the most, heat retention wise, was insulating the sill plate (or cripple wall area we would say out here….) rigid foam board foamed in with great stuff, all crwlspace vents covered and closed off, and the baredirt of the crawlspace sealed off properly. There is a a whole thing about this one the things to do part of this web site, good advice that works.

My house has solar, and we have for 18 years, and it provides all the power we use, we are battery backed-up grid intertied. I only have 2kW of panels, the house is all electric (no propane or gas) and we have to pump all our water out of a well. Hmm… habits may be: only laptop computers; power bars for electronics with switch to turn off; remembering to turn wi-fi off at night and when not needed, I estimate it is on 1/3-1/2 of time; LED bulbs; no big screen tv; wash full loads of laundry in cold water in general; we do not own a clothes dryer; solar hot water heater. On the other hand, we run the dishwasher once a day (ASKO); well pump and pressure pump for water; electric stove; electric hot water heater.

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