That is quite a big system you have in operation Julien and given the cost of electricity at current prices after a few years you will be quids in. Flying Pig other costs needs to be worked in, such as replacing the batteries. We recently replaced our 100 amps costing 500 GBP but they will last us for 4-5 years. Good advice Julien about doing research. We encountered several companies all with differing accounts of what to use ....heat exchangers, etc, those people with the smooth sales patter offering the best packages on finance, watch out. Be aware of the cowboys in the business, here today and gone tomorrow types. Warranty and after care is important if the units break down or develop leaks.
I agree with Guru and Julien in not going for a loan. We started out small and can expand if needed. In the future we might go for a wind power generator on the mountain ....horrors expected
