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My on demand LPG water heater works well for me. A tank style would be OK as well but the tankless works for be because I am often away and a tank style would be a constant waste while I was gone, but a tank style has its own advantages. A 20 lb tank lasts me a month and I am willing to fund that for the convenience. If it was ever a toss-up I would put the money towards more solar panels and batteries. Electricity is so darn useful. I swore I would never do this but I use the on-board electric heater built into the washer all the time. If I run a load late morning on a sunny day I am usually using power that was being thrown away as the charge controller throttled power to the batteries in absorption and float mode.
I would never use a full-on electric water heater for general whole-house use. An important point to be gleaned is that while conservation is not a separate technology like gas or electric heating, it is a major factor in its own right and factors into every decision you make. By doing laundry at the right time I can use electric heating for free.
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Solar hot water is about $1700 after all the rebates and tax deductions and with a family of 6 would pay for itself in about 18 months. We have an electric oven but do most of our baking in one of these
http://www.amazon.com/Camp-Chef-Camping-..._2?ie=UTF8&qid=1419966911&sr=8-2&keywords=camping+oven Not only does it sip the propane but being on our lanai it doesn't heat up the house to bake with it. We line dry our clothes. We do have an electric dryer but we hardly ever use it. I calculated it out and I came to the conclusion that switching our indoor stove or dryer to propane would cost more than we could recoup. Plus the hassle of fetching gas all the time. Our electricity bills are consistently about $115 a month.
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And as always, check to see what products qualify you for a rebate:
http://www.hawaiienergy.com/rebates
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Off-grid need not apply:
Rebates are available to residential electric utility ratepayers on Hawaii Island, Lanai, Maui, Molokai and Oahu only.
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quote:
Originally posted by HI_Someday
When I first joined this forum I remember reading about some folks who constructed their own solar water heaters cheaply using old water heaters in a plexiglass box. Or something like that. I think there are plans freely available on the net to build them inexpensively, if you're handy.
Does this ring a bell with anyone here and have any of you done or seen one?
i had mentioned it once on another related thread, probably around the time you joined. often referred to as a solar batch heater. i have yet to make one, but sure am looking forward to doing so. waiting to score an old water heater being discarded with the tank in good condition.
it's very simple. in a nutshell, the insulation is stripped off and a box is built for it (plywood w/ clear top angled towards the sun, reflective interior would be good, can insulate the plywood box, paint the tank black to best absorb solar radiation). the tank is plumbed into the water supply line leading into existing water heater. the intake and outtake fittings already existent on the old waterheater tank makes the plumbing quite simple. the idea is to preheat the water, significantly reducing the amount of energy needed to heat water. in lower Puna, i wouldn't be surprised if a batch heater alone would be sufficient to heat water. up here mauka, with plenty big shady trees and freeze azz water from the catchment, i would be using it as a preheater. i'm quite sure it will be well worthwhile in reducing energy consumption to heat water up here.
i can see ample evidence our old plantation style house originally had water pipes plumbed through the back of the fireplace as a heat exchange system. a neighbor has even more intact evidence of a similar setup. would love to figure out exactly how to restore that someday. preferably without having to rely on an electric pump for circulation.
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I would recommend solar for the hot water heater (we switched over about 2-3 years ago), propane for as many appliances as possible, and electric for whatever is left.
Leilani Estates, 2011 to Present
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We started out with the same system as Justin. We have since switched to grid tied solar for our electric. The initial price for the panels is costly but rebates will offset about 50% of the cost. I am loving our $20 a month electric bill. I still like having a gas stove. When the power goes out in a storm I have a way to prepare meals and heat water, although I guess I could do the same on a gas BBQ grill. We do not own our propane tank, we pay a $7 a month tank rental.
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I can't count the number of grilled cheese sandwiches I have ruined on electric stoves. Ate 'em anyway though.
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You'd think that a batch style solar water heater would be a good match for an on demand propane tankless heater but my instructions say not to use pre-heated water. There is a special model for that. I can report that it makes a difference how warm or cold the incoming water is. On cold nights like we are having now I run the shower with pretty nearly full hot, while on warm summer days it is more nearly half and half. The tankless water heater makes an attempt to modulate the heat input to get a constant temperature out but it is far from perfect. The solar batch heater combined with a regular tank style would work great I bet.
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"...for an on demand propane tankless heater but my instructions say not to use pre-heated water."
thanks for the heads up, Mark. i will look into that further. right now i have a regular tank style heater, but was hoping to switch to the tankless on-demand type soon. curious what the specs for the tankless type heaters list as the recommended temperature range of incoming water.
quick visual reference image search, wide variety of DIY versions:
https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1024&bih=639&q=solar+batch+heater+DIY&oq=solar+batch+heater+DIY&gs_l=img.3...5423.9155.0.10027.22.12.0.0.0.0.0.0..0.0.msedr...0...1ac.1.60.img..22.0.0.ioJWz-VMJz0
