I've lived in the southern US my whole life. An average bill of $500/month is a lot. The only way I could see that is if most or all of the following are true: very large house, very old A/C, using electricity for heat in the winter (not a heat pump), unusually high rate, setting thermostat below 70 all the time.
My house is not huge, but it is nearly 70 years old and doesn't even have insulation in half the walls. My electric bill rarely gets above $200/month even when the high temp is 100 most days. My a/c is not particularly new either, I think it's approaching ~20 years.
I used to get one or two electric bills every year less than $200 back in the noughts but the weather's not been cooperating of late. 40 year old house, 2500 square ft under air or heat pump, summertime thermostat set at 79, located in an unusually arid part of s/w Florida. No insulation in the cinder block walls and very thin insulation in the attic. No shade foliage to the west or to the south. Tons of heat gain through the south facing side: Previous owner had to have equity in a sliding glass door company, the entire south side opens up with sliding glass doors.
I have a solar powered attic ventilator on my must-buy list but I'm worried about puncturing the brand new roof's membrane.
The only attic ventilation now is passive through the soffits and ridge vents. Active ventilation was on my list but now I've struck it off based on your post. 3/4 of my attic space is vaulted -- I can't get flats up there, maybe it can be blown, but if it's blown how do they go about inspecting it for proper application? Or is it more like BGA assembly without X-ray inspection (spray and pray?)
For blown insulation (I think you mean fibers, not expanding foam), I think the installation method integrates a basic check, i.e. you cut small access holes on both ends of a space you are filling, and it is pretty obvious whether bulk material makes it to the other end to spill out. You probably need a stud-finder or similar to map the spaces between rafters, fire blocking, etc.
The best way to plan or inspect an insulation job is to use an infrared camera to observe temperature gradients. You can see hot or cold spots where heat is conducting or convecting through the structure.
Maybe I'll luck out and the vaults won't need remediation. Yes I was thinking fibers, not foam. I'm sure I'm underestimating the effort eeded to do a proper job on the vaults within the things' narrow confines: Access to two of four vault edges doesn't seem possible without punching through the gables from outside.
Thank you for the practical suggestions on moving forward. Email me in profile if you're in Largo or Sarasota FL sometime and I'll buy you a brewski or coffee or something.
For retrofit, I think it is more common to cut 1-2 inch openings through the ceiling or wall face (i.e. cut through plaster or remove pieces of paneling), blow the insulation, and finally patch those holes. And, this pattern will repeat every 5-10 feet, since the bays should be physically divided along their length by fire-blocking if built to code. Each blocked section will have to be filled as a separate step.
Disclaimer: I'm not an HVAC professional, but I did apply closed cell foam insulation to one of the rooms in my house.
In my experience, the spray does a very good job of sealing the joints where applicable. That's probably not the right type for an attic, but more insulation would generally be better than less.
That's not a particularly scientific approach, but when we're talking about old houses, you're almost never going to be able to do everything the way you want 100%.
I'm trying to envision what you did. Were you sealing up penetrations in an exterior surface or along a joint edge or were you filling voids in for ex the wall? I had good results filling a nasty opening around a water pipe with the spray but it didn't last because I failed to observe the warning about UV degradation and the material eventually flaked away.
I'll check out the awning option - great idea. The sun's so high in the summer they wouldn't need to be deep at all.
The previous owners ruled out trees by planting hundreds of sq ft of concrete topped with crumbling fragile coolcrete. But for the lack of soil what I'd really wish for are trellises covered moonflowers, passion flowers, and all sorts of fast growing beautiful vines. Maybe I still could do this with long rows of planters. Thank you for the excellent suggestions. You also get a brewski/coffee if you're every by Largo/Sarasota FL, email in profile.
With proper architecture [0], you can have a much more efficient house that requires little if any air conditioning. It'll look much nicer than the typical McMansion too.[1]
A custom net zero home, which is what you've linked here, sounds pretty damn expensive. Unless money is no object, you're probably better off slapping some extra solar panels on your existing McMansion.
The science direct article content was excellent for new builds. Up until the early 70s, when draining Florida was still a thing, before depletion concerns, some neighboring homes had an air conditioning mode routing pumped shallow aquifer ground water through the air handler for cooling, and dumping the warmed water. I wonder if a heat exchanger to a deeper aquifer is a practical alternative.
You spend $6000 a year on electricity? Are you running an aluminium smelter in your back yard?