Because of the reduced heat transfer from inside to outside, it will now cost us less to cool our house in summer and to heat our house in winter. In fact, as the weather in Melbourne has cooled, we’re already noticing that the temperature in the upstairs rooms doesn’t drop as quickly at night as it used to.
(We used Solar Savers to get quotes for this insulation installation too, by the way.)
What next?
Those are the only energy upgrades we had planned for this year.
With an approximate halving of our electricity bill, it should take us roughly seven to eight years to pay off our solar system investment. This includes the cost of regular cleaning and maintenance of the equipment we’ve just had installed.
Electric vehicle
If we drove our car a lot, upgrading that to an EV and getting an EV charger installed would be next on our list.
But we drive so little that we only fill-up on petrol every six to seven weeks, so upgrading to an EV is not worth the investment. (And EVs sure are expensive, especially first-hand ones!)
Household appliances
We’ll probably look into upgrading our stove and hot water system next, since both of those currently run on natural gas.
I don’t think that’ll happen for at least another four or five years though.
Home battery
Depending on how well our solar panels perform in winter, though, we might consider getting a home battery installed sooner rather than later.
The largest chunk of our annual electricity expenditure goes towards heating our house in winter, especially at night. If we find that our solar panels are generating enough excess energy during the day in winter – energy that’s enough to cover most or all of our nighttime heating – then it makes financial sense to store that excess in a home battery to use at night.
This will increase our payback time on the whole system, of course. The payback time on a home battery is about as the same as it is on solar panels: seven to eight years. But if the winter daytime excess energy numbers are good, then the total payback time of the combined systems might increase to only ten years instead of doubling to fourteen or fifteen years.
I’ll keep an eye on the stats over winter and we’ll make a determination either way in summer next year.
Enough solar for now
For now, though, we’re just going to enjoy having the sun power about half of our lives.
Sometimes there isn’t even much for the sun to power. A couple of weeks ago, for example, Nadia was teaching at uni and I was working from home. Even though it was a cloudy day with intermittent drizzles, our solar panels still managed to generate enough energy to export most of it to the grid!
(Things would have been different had I been running the air conditioner, dish washer, or washing machine, of course. But that’s not something we do every day in summer.)