Electricity on Oahu runs about 32-35 cents/KWHr, and the vast majority of homes were built before people started using air conditioners.
Imagine: double-wall construction with no interior insulation (or even single-wall construction in some plantation homes), single-pane untinted windows (or even jalousie windows), uninsulated attics, roofs made only of sheathing with tarpaper & shingles, no moisture barrier house wrap, no foam sprayed on air gaps. That's standard. No, that's actually considered pretty good quality around here. No brick. Maybe ornamental lava rock. Concrete slabs-- the soil is too rocky for basements.
A number of homes are being retrofitted (at horrendous expense for construction materials) but most residents don't do the payback math to make a huge capital investment to avoid high monthly (recurring) bills. New homes are generally being built with insulation and passive cooling, but again the tendency is to build a gigantic insulated box in the middle of a bare, exposed lot with a split-system A/C plant running 24/7. The median single-family home here costs $600K (mostly for the land) and not much money gets spent on energy-efficient construction materials. But the trend is improving.
So last week spouse and I visited the local "Parade of Homes" winners. These homes were built for energy efficiency with insulated walls, reflective solar roofs, double-pane tinted-glass low-e windows, heavy-duty seals on windows & doors, solar water heaters, and high-efficiency A/C. These are touted as the island's most energy-efficient homes, but their idea of "energy-efficient" is still a huge insulated box in the middle of a bare, exposed lot.
The electric bills are touted as a "sustainable" $200/month. That's considered a big deal because only about 400-500 KWHr/month goes to A/C.
We don't have a heating or a cooling system. We have a heavily insulated roof (2" icynene panels) and R13 fiberglas batts in the walls, with reflective foil (to keep the heat out) in the exterior of the walls & roof. No attic insulation-- just lots of ventilation with solar exhaust fans. Large screened lanai doors & windows for tradewind cooling. We have ceiling fans but the last round of roof insulation was so effective that we haven't been using the ceiling fans. If anything it's a bit cold here in the mornings, especially in winter. CFL bulbs, a microwave convection oven, and EnergyStar appliances.
We have solar water heating and an older photovoltaic array. We generate and use about 140-150 KWHr/month. Our electric bills are $13.80/month, which is the minimum customer fee for the privilege of our residential net-metering connection to HECO's (mostly) rock-solid grid voltage.
But we're paying over $100/month for sewage. The island's sewage infrastructure is rotting away and it's a huge capital expense to do the micro-tunneling to replace it with modern piping.
