interesting topic - I was thinking of doing this myself but was really unsure on the benefit.
Reading on the specifications of the H2O Labs 300SS:
http://www.h2olabs.com/p-55-stainless-s ... arafe.aspx
- interesting that they note that they use a lower wattage to slow the boiling process so that:
1. they don't need a splash shield
2. they allow the VOC's to boil off first - not as part of the water that is distilled - well, after reading it again, it really does not say this, but they infer it for sure " Larger heating elements in one gallon units can cause water to mix with VOCs and other contaminate"
So - pardon the engineer in me - there are 2 side for me to consider 1. the cost side and 2 the health benefit side.
Let's look at cost first.
They rate the unit at 580 Watts. They say you can make 4 gallons per day, so I assume it take 6 hours to produce 1 gallon. (24 hours/4 gallons = 6 hours / gallon). Depending on the cost of electricity in your area you can calculate your electric cost to make the water by looking at the kWh (kilo Watt hour). A simple example is that if you have a 1000 watt heater and you leave it on for one hour, they you used 1 kWh of electricity. In the US, we buy electricity in kWh. (the meter on the side of your home measures usage in kWh).
Back to the distiller - 580 watts = 0.58 kW, we run it for 6 hours, so 6 hours * 0.58 kW = 3.48 kWh of electricity consumed. Then you need to know the energy cost where you live, in Michigan I pay anywhere from $0.12 to $0.15 per kWh depending on how much I use and the time of the year. so for me I would use $0.522 of electricity at $0.15 per kWh to produce 1 gallon of distilled water. (0.15 $/kWh* 3.48 kWh = $0.522) or as low as $0.41 per gallon.
On average I pay about $1.00 per gallon. Using my lowest cost of electricity, I save $0.59 per gallon used. Not looking so hard online I see the unit sells for ~$250.00. So, after I produce 423.7 gallons, the unit pays for itself ($250/$0.59 per gallon = 423.7 gallons). Only factor used in the electric energy cost...
So, part 2 is the health benefit - of which you can apply no cost to, only need to understand the benefit vs risk in my opinion
My distilled water is sold in HDPE (recycle number 2) bottles. Interesting for my is that so is the milk I buy. I did look at one "purified water" bottle that I have and it is made from PETE (recycle number 1). The distilled water is coded with the bottled date and the best by date. In this case it was bottled October 22, 2013 at 10:40 with a best by date of October 22, 2015. So, somewhere, someone decided that a 2 year shelf life is "safe". The purified water bottle has no obvious bottled or use by date - it is coded for lot traceability as required by law though - just not human readable. For some details on the recycle numbers take a look at:
http://www.nationofchange.org/numbers-p ... 1360168347 take a special interest in the health concerns for each type of plastic and what you use everyday that is stored in these plastics...
Back to the distilled water - so knowing that it is produced from HDPE is not much more useful than calling it plastic, but at least we know the molecular structure of the basic plastic that it is produced from. However, we do know that HDPE does not contain any BPA, this was a problem with the polycarbonate plastic bottles. (
http://www.nrdc.org/thisgreenlife/0902.asp) Then if HDPE is safe, why the expiration date? Some interesting items I found were related to a 1987 rule in NJ, but others say it is just based on the water running on same equipment as other bottled products that do expire. Here is a good overview -
http://blogs.smithsonianmag.com/smartne ... tion-date/
But all of that is drinking water and not water that we breath. To me, the human bodies digestive system is designed to handle multiple contaminates and filter them before the body "consumes" them. Think of the liver and its functions. (I am not a doctor, just an engineer) The human lungs on the other hand do not have any protective systems that I am aware of. So, to be safe, the cleaner the water that I breath the better.
Overall, to me there is still room for debate on this. I will use distilled water all the time at home, occasionally when I travel I use tap water that is known safe to drink when I can't get at least bottled water or preference is distilled water. The question here in my opinion is to purchase or produce it yourself.
other thoughts?
Paul