Also where are you getting these $20 gas bottles. Walked past the price tag of the bottles at bunnings the other day and they are $27 for a 9kg bottle.
We country folk get to pay 27 at green shed, city stores have to compete with bcf ( my local bcf charges $23 for a fill), have a local supplier who dose $20 or $22 from memory, try your local bbq places too
Gasbottlerefils.com might dig up a gem locally for you
Down here, all of the bottle swap places have them for around $24 to $27, but they are only filled to 8.5kg, no matter whether its the regular 8.5kg cylinder or the larger 9kg. You may be getting a better deal by getting them refilled.
Depending on your solar metering setup, most systems these days allow you to use the power you generate.
If you're stillin during the bright daylight hours and you're generating more than your using than its free. The exception now is that it's winter as there's less daylight, so you'll end up paying for the power when it gets dark.
I just suck it up and see it as subsidised power...
equipment: 50L Beer keg boiler with two 2.4kw elements, a kegland controller, 2 inch Bokakob aka Billy Bob Boka and Jack the stripper a 2.5inch shell and tube condenser for pot mode or stripping... Building up to getting a 4 inch plate still
I'm running gas now and electricity last yr. There's nearly $500 less on the bill this yr and I've made about the same or slightly more booze this yr! My gas costs are under $100 gas is way cheaper than electricity in my experience.
equipment: 18 gal keg boiler on its side on wheel's with fill port, 1in drain and 2x2.4kw elements 4in 5 plate modular blockhead with optional infusion basket