RIP PiP?

I hear ya. When I had my 1500sf "bachelor pad," I replaced the 1975 HVAC system with a hi SEER system that literally cut summer bills by more than 50%. Then I went on a "no incandescent" campaign and replaced them, and CFLs, with LEDs. That got my average consumption over the past five years to around 300kWh/mo. Of course, the PiP then added about another 100kWh/mo.

Now that I moved into my wife's newer place, I've been on a mission to improve efficiency: no incandescents, all LEDs (a couple of incandescent 12v landscape lights notwithstanding). That really had minimal impact. Even at 3am, the home is sucking about 350-500W/hr, and this past summer I saw electric consumption peak at (I'm embarrassed to reveal) 1500kWh in summer. That over-$400 bill was the last straw. Even though this place was built in 2003, the A/C unit seems to be horribly inefficient. So, once we get the solar installed (hoping sometime next month), next efficiency steps will be to re-tool the HVAC system with high SEER (>15) components.

None of this will help the fact that this home has LOTS of windows and French Doors (heat loss/gain) and a koi pond (pump running 16h/day), but my goal is to have every kWh generated from solar be sufficient to power my PiP and a future Elan Muskmobile.

 

Yes, she electrified me. And that's Plugz. (Change to mp3)

 

How good are the windows? My parents replaced windows with brand new 3-pane ones last year and those are more effective at keeping out outside temperatures than their walls. I suspect a lot of your losses are through walls because most homes in California have zero insulation there.

 

Looking at the hour-by-hour consumption over a one year period and playing around with SQL queries, I doubt the issue is insulation, although that's on my list (just lower down the list) to consider. I think the key is the very low efficiency AC system. We've had days of 50kWh/24 hours consumption during the hottest days last summer. Yeah, that's a lot! Those don't occur during cooler weather, where we can get down to "only" about 20kWh/day.

Our gas bill for heating, in spite of us having a "California cold snap" (that is, LOW temps almost at freezing and HIGH temps in the high 40s/low 50s) seems reasonable. I'd expect a severe change during cold periods that would mirror electricity use during summer if insulation were the primary culprit.

 

Well keep in mind that if you've got gas based heating the jump will not be as significant given pricing and efficiency issues.

 

What about solar gain from windows and heat trapped in the attic? My grandmother's house gets terribly warm upstairs in the summer, especially in the rooms under the attic and especially in the room with a west facing window, but the downstairs, which is shaded by an awning, can stay pretty cool in the summer, even with two west facing sliding glass doors and two large windows.

 

Virtually all French doors and almost all windows are either north or east facing, with the garage and well shaded front yard facing south and west. Very little impact from direct sun exposure.

I've not yet been up to the attic to check, but an attic fan indeed sounds like a cheap improvement that would pay for itself pretty quickly. I'll ask the solar contractor (also a roofing contractor) about doing this as an add-on.