Anyone know if the LPG bottles workout too expensive?
Using the Immergas HE35 as an example, LPG consumption varies from 130Mj/h at max and can modulate down to 30Mj/h when just ticking along and maintaining water above a minimum temperature.
The following are bottles you can manage without too much difficulty in moving around without material handling aids
1kg of LPG works out to be 49Mj
8.5kg (9kg bottle) of LPG works out to be 416Mj
45kg of LPG works out to be 2205Mj
You could go with a 210kg bottle which works out to be 10290Mj.
After this you'd be looking at 500kg or 1T+ stationary tanks which gets refilled from a truck.
I hope this gives you an idea of what a boiler could use and how often you would need to fill or swap the bottles.
Have you thought about using solar water heaters to heat the water as much as possible and only using the gas boiler to emper the water when it falls below a minimum temperature, say 65 degrees?
Thanks for taking the time to post all that great info.
Looks like LPG will be cost prohibitive to run....
I have been thinking of all the options, we are building a new house and have spent a lot on things like treated timber extra insulation, sisalation etc. So funds are starting to run low.. Ideally I would have a large storage tank, solar, and geo heat pump as we are on 10 acres. But once I started pricing it up I freaked out. Also it seems that Australia doesn't have the best of what's available else where in the world, although this is changing.
At this stage I am thinking of running all the pipes for the radiators myself prior to the gyprock. That way it's all there for when I decide what way to go. A wood fired boiler seems like a good option in the interim.