Solar PV is now the most cost efective energy source.

[cmhansen]

I suppose it seems like a big deal to someone with no experience heating with wood but it's like any other regular household task - washing dishes, clothes, sweeping floors, watering the garden - or clearing snow off the solar panels and maintaining the battery bank...

At least the point got across there's a great deal of variation under the term 'firewood'.  If chores are 'no biggie', why not go horse and buggie??  And forget chainsaws / hydraulic splitters / etc and go back to just an axe for that matter.  Trade in the tractor for a hoe, after all it will 'warm you twice!'

[mtdoc]

I suppose it seems like a big deal to someone with no experience heating with wood but it's like any other regular household task - washing dishes, clothes, sweeping floors, watering the garden - or clearing snow off the solar panels and maintaining the battery bank...

At least the point got across there's a great deal of variation under the term 'firewood'.  If chores are 'no biggie', why not go horse and buggie??  And forget chainsaws / hydraulic splitters / etc and go back to just an axe for that matter.  Trade in the tractor for a hoe, after all it will 'warm you twice!'

Well, in spite of the hyperbole, the fact is it really is not that much work to heat with wood if you buy the cut and split wood.  I know several elderly people (70s and 80s) who do it.  It takes maybe 10 minutes a day in total to bring wood in, load the stove, tend to the fire and occasional ash removal (which just takes a couple of minutes once a month or so)

If one chooses to cut, haul,  and split their own wood then that does involve some regular physical labor - I'd guess maybe 4-6 hours for a cord if you know what you're doing.  But nothing wrong with hard work - it's good for the mind and body (and cheaper than a gym membership!).  And in that case the wood does  warm you multiple times then!  I've done it in the past but these days I mostly buy my wood unless I'm cutting and splitting downed trees on my property.  With a good wood supply my wife and young kids have no problem keeping our home warm with minimal effort, even if the power is out and there is no sun.

[HackedFridgeMagnet]

sry if off topic. will get back to it soon.
I guess a cord is some quantity of wood, how much? Here we say we buy by the tonne but really it is by volume. Locally it is about  US$50 per cubic metre split and delivered.
My neighbour cuts my fallen trees and gives me 1/3 cut and split, it's a great deal for both of us.
Love having a fire going in the living room. Though it is a bit messy.

I am thinking of getting some solar but I may as well do a grid connect, and synch the heaters to run when the sun is shining, as we only get a 7c per kWh for generated energy.
Then put enough insulation and thermal mass into the house to make the best of it. 

[electrodacus]

sry if off topic. will get back to it soon.
I guess a cord is some quantity of wood, how much? Here we say we buy by the tonne but really it is by volume. Locally it is about  US$50 per cubic metre split and delivered.
My neighbour cuts my fallen trees and gives me 1/3 cut and split, it's a great deal for both of us.
Love having a fire going in the living room. Though it is a bit messy.

I am thinking of getting some solar but I may as well do a grid connect, and synch the heaters to run when the sun is shining, as we only get a 7c per kWh for generated energy.
Then put enough insulation and thermal mass into the house to make the best of it.

It is not off topic since we discus the comparison with other sources of energy and is good for people to have an idea of how to compare them.

I'm also new to the cord as unit of measurement (I'm used with metric) and this measurement refers to volume (not very precise same as with cubic meter) since it depends how densely packed the wood is and also what type of wood.
If I'm wrong then someone will correct me but a cord of wood is 8ft x 4ft x 4ft and that will be 128 cubic feet or about 3.62 cubic meter (so your price of $50/m3 is not bad).
Again this is volume 128 cubic feet and actual volume of wood will be less around 85 cubic feet since there is a lot of air in there
I used this source https://en.wikipedia.org/wiki/Cord_%28unit%29
Also from there and confirmed with other sources you get 6477kWh of energy from that wood (seasoned dried read oak). And with a fairly ideal high efficiency stove with 70% efficiency you get around 4500kWh of usable heat and that is exactly what my house needs in an average winter season here.

Assuming you can get one cord of this quality wood for 200USD / 4500kWh = 4.4 cent is the cost of unit of energy and that is higher than natural gas at my location that is why I used natural gas in my comparison with solar PV.

[CCitizenTO]

It is shocking when you see systems like http://www.sunbandit.us/ selling almost a conventional water heater in excess of $9,000 for the system. Just how does that pay off?  It is a conventional water heater with one extra heater for grid connect (3 total) a couple of panels and enphase converters.  I heat water with PV and the home made PWM converter to keep the panels at power point only costs about $25. Failing to keep the panels at power point will result in 50% power loss.  Your basic cost is almost just the panels.  If you design the system as supplemental heating and use only the lower heating element for PV, nearly 100% of the panels potential power generation is used 365 days a year. That surpasses almost anything else you can do with PV at a much lower hardware cost.  $500 for just two panels is a cheap way to get into solar.  Shamefully simple.  Just a nano,  a couple FET and some capacitors as the storage bank.

Well a home-made solution may work for you. However, when you start to deal with the scale that mass marketing requires you have to deal with testing, certifications, building code compliance (Electrical, Plumbing, Gas, etc...) and probably a ton of other bullshit to basically declare that it's safe to use in someone else's home on top of the money for setting up a corporation so if your thing does burn someone's house down you don't lose everything. All those cost money and someone isn't going to do something like this at cost so they're going to want to turn a profit and they'll try and get as much money as the market will bear.

[foursquare]

Hi Electrodacus,

We never thought this was possible, but it now is. It's amazing how science has brought us beyond our expectations. Back during the times, nobody even thought electricity would exist, and now, there are solar panels that can convert solar power into electricity.

[Seekonk]

The sunbandit utilizes all available UL rated components that you can buy for less than $3,000.  They don't actually make anything but the label.

electrodacus, you may be in violation of U.S. Pat. No. 5,293,447 for your switched resistance heating system.  Watch out for trolls.

[hendorog]

The sunbandit utilizes all available UL rated components that you can buy for less than $3,000.  They don't actually make anything but the label.

electrodacus, you may be in violation of U.S. Pat. No. 5,293,447 for your switched resistance heating system.  Watch out for trolls.

IANAL but don't patents expire after 20 years? That was filed in 1992.

[electrodacus]

The sunbandit utilizes all available UL rated components that you can buy for less than $3,000.  They don't actually make anything but the label.

Yes all those components are off the shelf they do not seems to have anything other than offer a complete package.

electrodacus, you may be in violation of U.S. Pat. No. 5,293,447 for your switched resistance heating system.  Watch out for trolls.

I just checked that and while is a bit vague and hard to understand (probably as most patten applications) seems possible to be something similar to part of what I do in the DMPPT.
Still if this is the same idea I use it is funny that someone will allow such a simple idea to be patented.
Anyone with basic knowledge about electricity can come up with this idea on their own in a few minutes since is nothing more than simple Ohm's law involved.
How did you found that patent ?
The patten seems rally old also more than 20 years.

[Seekonk]

There are a lot of PV water heating patents.  Each are as vague as the next. There is another one that says "any adaptive control."  That covers a lot.  USPTO doesn't work like it used to.  Google search seems to have taken that searching over. I just did a search for "photovoltaic water heater." So, you can just invent an "unspecified control system."

[electrodacus]

There are a lot of PV water heating patents.  Each are as vague as the next. There is another one that says "any adaptive control."  That covers a lot.  USPTO doesn't work like it used to.  Google search seems to have taken that searching over. I just did a search for "photovoltaic water heater." So, you can just invent an "unspecified control system."

That patent you mentioned while a bit confusing to read seems to be fairly similar to the DMPPT heating part (the DMPPT combines that also with battery charging).
The idea was useless at that time since PV panels where much more expensive than  thermal solar panels.
In any case that is an old patent and hendorog mentioned above that one is expired since it has more than 20 years since the application was made in 1992.
That is maybe a good thing since I think an idea that had a patten and expired can not be patented again. (not sure that is just what I think makes sense)
I will never patent any of my ideas since I find that a waste on money and resources from my part and hinder progress in general (my opinion).

[CatalinaWOW]

USPTO screws up a fair amount.  I have heard that the Field Effect Transistor was patented three times, twice before it could be fabricated.  Once in the first decades of the twentieth century, and a second time before WWII.  Unless you are planning to hire an army of lawyers to defend your turf, the patent system is best left to the large corporations to play their games with.

[moz]

I am thinking of getting some solar but I may as well do a grid connect, and synch the heaters to run when the sun is shining, as we only get a 7c per kWh for generated energy.

We get 5c, but feed the grid anyway because the net benefit is significant. If nothing else the panels shade the roof in the summer The way the market is at the moment the net install cost after selling the RECs is very low. Although one tip: if you have tiles on the roof I suggest looking art replacing them with insulated steel before putting up PV. Tiles are awful, especially old clay tiles.

Then put enough insulation and thermal mass into the house to make the best of it.

That's where you can win big. Australian houses make me cry, there's so many easy wins left on the table. Sadly most of them are nigh on impossible to retrofit - albeit sometimes only because the local government won't let you... or you won't be able to sell the house "because it looks funny". Maybe not an issue for most, but it is for us.

We ended up building a "shed" on the western/back side of the house that is well insulated, but also shades some of the exposed brick walls which helps a lot with summer cooling. Having that as a refuge room on hot days is almost magic - the modern split system aircon uses about 500W to keep that room 20 degrees cooler than outside, and we have ~3kW of PV being generated on those days. Turning aircon off as the sun goes down doesn't hurt much, and if we did it again I'd go for a much thicker, more insulated slab underneath and have a pipe to divert the aircon output through the slab to pre-cool it for the overnight. Half a metre high concrete box full of gravel, pump air in one side and draw it out the other as a "cool store".

Also, in Oz it's usually cheaper and more efficient to have a solar hot water storage system than PV plus heat pump. We have good local skills in the area and while maintenance is a little higher (heat pump HWS fail too!) the roof space and dollars required is significantly lower ($4k rather than $10k for us)