Keep in mind much of the thermal load from the roof/attic radiates into the house from sundown until sometime in the middle of the night.Cheezmo wrote:Area 3
The house is 4500 square feet wide open 2 story entry. A beast to air condition, but we have Nest thermostats that are helping.
We replaced our roof about 6 years ago and I passed on the radiant barrier because OTA HD was a big deal for me then and it would block the antenna. Since I don't care about that any more, I should look at doing something in the attic. Torn between insulation or a radiant barrier (or both). Of course reducing our A/C load during peak sun hours would actually be counterproductive at this point
You have 3 periods in relation between the AC and Solar PV.
1. Your solar panels generate power in the morning when the AC load is minimal
2. Your solar panels generate power in the mid day and after noon while the AC load is high
3. Your solar panels don't generate in the evening when the AC load is still high.
To me period 3 is when my house is the hottest and that is where you either pay up front for insulation or as you go for the electricity to cool the house while it's still very hot out but dark.
Now 3 can be negated by opening up the house to outside air once the outside temp drops but humidity and allergens are enough of a reason for most to call that a no go. If it works for you vents, fans, windows, sliding glass doors with screens, etcetera can vent the house after dark.
7c/kwh is cheaper than just about anywhere in the US but even then I'd be seriously looking at reducing my AC load considering the sheer amout of heat you deal with.