by gg3 » Thu 11 May 2006, 08:40:24
Just got my latest electric bill. 265 KWH for a period of 29 days between meter readings. Total bill including gas, $60.24.
Re. the clothes dryer.
Look up "spin dryers" on shopping.yahoo.com. What these are: a high-speed centrifuge that handles about 5 lbs. of laundry at a time, at 3200 rpm, takes about five minutes per load, and reduces time in the heated tumble-dryer by about half.
In the US the brand is SpinX, cost is about $450. These are built like military spec and should pay for themselves within a few years in most cases. (And anyway, it's rewarding to see your electric bill drop noticeably after you install one.)
Or you can get the same results with a twin-tub washer (in the US, Danby DTT-420), which has a high-speed spinner unit and is also probably the most energy-efficient washer anywhere, at about 10 to 20 watt-hours (yes, watt-hours) per pound of laundry (e.g. 0.06 to 0.12 KWH for a 6-lb load, the higher figure for "sanitize" cycles using bleach & an extra rinse). This costs only $300 plus shipping, can be bought on the internet if you can't find it locally.
In other countries there are other manufacturers for spin dryers, and the prices are typically less than the SpinX. Either way they will pay for themselves quickly.
Re. the fridge:
In the US, 600 KWH/year is now considered pretty typical for a standard size fridge. The one in my place is ancient and uses about twice that much (which is about half of my total electric bill).
The best-practice conventional fridges are rated at about 331 KWH per year (e.g. Sanyo 10 - 14 cubic foot models). SunFrost claims to get this down to 110 KWH / year but costs $2,500 new and there has been some controversy lately about these units (e.g. power consumption levels, quality of workmanship, etc.).
This month I designed a refrigerator/freezer that should only use about 160 KWH per year, which is about half of the best-practice conventional fridge and only a little more than the SunFrost, at a projected price of about half that of SunFrost. My estimate of 160 KWH is not a wild guess or pure theory, it's based on empirical data from work done by others.
As soon as I have a chance, I'm going to build one of these and see how it actually performs. If it does the job as planned, some friends & I are probably going to start making & selling these commercially (which is why I'm being shy about the technical details, in fact it's actually quite simple). We may also include a Kill-a-Watt meter with every unit sold, so buyers can verify the lower power consumption for themselves (and then start looking at the rest of their appliances).
The next thing to tackle is the stove and the oven.
Conventional electric ranges use from 500 to 2,500 watts for each of the heating elements on the stove, and typically 4,500 watts for the oven. Even if these things are only used for a short period of time each day, they are still a large power drain if you're using off-grid power. We're not exactly certain of the approach we want to take to deal with this, though we were saying the same thing when we started on the fridge project. So, we'll see what happens...