ICF

Our projected HERS rating will be very low (without solar) - with solar we should be a net producer.

We've POURED money into roofing / insulation, concrete sandwich panels, sealed everything like CRAZY, triple paned windows (PassivHaus rated), insulated the slab, etc...

First of all, we built a modest-sized home (1400 sq ft) for our retirement home. I spent a lot of time considering orientation on the lot, plus room and window placement. I built it out of ICF, with R-50 insulation in the attic. Decent quality windows. We used super-efficient mini-split heat pumps instead of central HVAC. We also used LED lights throughout. Not that everyone has this option, but we built in an area of fairly mild weather (SC). As a result, our total HVAC cost for the YEAR is around $200. We go months at a time without running it.

Even though our house is DIY, I doubt that it will actually pay off in our lifetime. In our last house in FL, power bills sometimes ran $300 a month during A/C season. It doesn't really matter to me what the ROI is; we love living in a quiet, strong house that is cheap to 'feed'. Comfort is a big factor, and the entire house is very even in temperature, with no hot or cold spots. The mini-splits are virtually silent in operation, both inside and out. It's nice to know that we're saving energy as well.

We're custom building our first and last house and should be finished in August after a three year saga. It's large, but I think has an efficient design with very little wasted space. Built from 10" Integraspec ICF exterior walls and Litedeck ICF floors, we installed low air infiltration Soft-lite windows and use both spray foam and R-50 insulation in the attic. Geothermal heating/cooling combined with central lighting controls to keep energy usage down. We would like to install solar at some point and use Tesla Powerwalls for car charging and backup energy, but that will have to wait a few years. Due to the shape of the lot, we couldn't optimize house orientation for passive energy, but we did the best we could with the design.

As for costs, building the way we did is definitely more expensive up front. Because of our first builders mismanagement, mistakes were made so it's difficult to calculate how much more the ICF cost over stick built, but I would guess somewhere between 7-10% more. The Geothermal was more expensive to install over natural gas, but I think we can recover the costs in heating and cooling efficiencies over the life of the house. Less so since we're in an ICF house with low air infiltration. Our Soft-lite windows were a bit more expensive and it's difficult to compare them against the big three window companies since materials, build qualities, and buyer expectations are vastly different. The windows we got have high quality construction and materials and I don't expect to ever have to replace them. The low air infiltration contributes greatly to our efficiency.

Despite all these implementations,I have no illusions about attempting to recover the efficiency improvement costs because I would surprised if we ever will. To us, it was about creating a durable legacy house to keep in the family while providing comfort and peace of mind as we eventually age in place. Living there will be very comfortable and the expected lower operating costs will be a nice bonus. We're just breaking 40 this year, so with care, we'll have at least a few decades to enjoy the house.

Insulation after AC installed. I have no comps for AC before and after insulation because it was less than a week between the installs.

AC is SAVING utility bills compared to evap cooler because of the lower water bills.

The main gain is comfort - the ceiling no longer radiates heat.

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Shade screens on east windows - drops the room temp about 15 degrees F on that side of the house. Cost $10-30 each DIY

http://lazygardens.blogspot.com/2016/12/diy-no-tool-shade-screens.html 

Lazy_gardens I'd like to see your shade solution, but it says it doesn't exist

I don't understand the question. Are you suggesting that it is possible for a new house in FLA to be "UNDER insulated" and have "OVERSIZED HVAC equipment". Many communities have amended the IRC/IECC to require even stricter standards.

Remember that each additional inch of insulation saves less than the one that precedes it. Before considering additional insulation and more efficient equipment take a careful look at windows, shading, smart control systems, lighting, attics and exterior materials.

kirkhall here is the right linkLazy Gardens Shade Screens

I was very interested in the prospect of using our gut remodel/addition to invest in energy efficiency. What I found was that current code and widely used materials/appliances have gone a long way towards making new build much more efficient than it had been. We live in NJ, so we can get cold winters and hot, humid summers which necessitate frequent HVAC use. For the more cutting edge technologies in insulation, building materials, etc. I found that the upfront investment in both material and labor costs was dramatically higher than our expected return. And any future problems to come out of it would require a lot more work and money to fix than going with more widely used materials.

Just having almost all LED lights dramatically cuts down on energy usage for lighting. A well designed HVAC using common furnaces/AC (for us that meant 95% on the furnace, 16 SEER on the AC) and easily programmable thermostats significantly reduces energy use and increases comfort. Just insulating properly up to code results in a ton of energy savings. Most windows are pretty efficient these days.

So doing nothing out of the ordinary we more than doubled the size of our 1950s house, and our energy bills are the same as they were previously.

Switching to a front load washer (when the old topload died) made a huge difference in our water bills, switching to efficient shower heads just a small difference. Our new furnace cut (replacing the dangerous old one) our gas bill by a lot. I've insulated the pipes where I can reach. I put film on the windows each winter (well, some of it just stays up all year) and that is an enormous energy saver. I'd love new windows altogether, but the film costs a tiny fraction of the $30k + new windows would be (because I want to change from all double-hung to some casement) and we'd never recoup it.

JDS I
don't understand the question. Are you suggesting that it is possible
for a new house in FLA to be "UNDER insulated" and have "OVERSIZED HVAC
equipment". I didn't note NEW house. But yes, there is a VERY high percentage of homes that are UNDER insulated here and have OVERSIZED HVAC systems and to this day, is VERY common. This is information I have received from a wide variety of sources with close ties to the industry.

We live in a rental house, we had to have the HVAC serviced a week ago and they servicing company is one of the larger ones in the area. I asked specifically about oversized units in residential houses and both techs agreed, a very very high percentage of the houses they service have oversized equipment. That can lead to other issues with mold and moisture in the house. The HVAC in this house is oversized.

Back to my question which was "What have you either done while building a new house or done to your
existing house to improve your energy efficiency? Cost of changes ?
Savings or anticipated savings ?" It doesn't specifically have to pertain to HVAC or insulation mind you but, those are TWO HUGE areas for Floridians.

Many houses in FL are real energy hogs. Our house, built in 1981, had NO insulation in the walls, single pane windows, and R-13 batts in the attic. The duct work for the A/C was in the hot attic, above the skimpy insulation.

Virgil makes a good point about carefully siting the house. As I said before, I put a lot of research and thought into this. The roof has large overhangs to shade midsummer sun. We have deciduous trees all around to screen the hot sun, but permit winter sun to enter. The garage is on the west side of the house, sheltering the house from the hottest sun of the day. A deep porch shelters most of the front of the house. Our walk-out basement will someday be living space. Because it is partially underground, it is very temperature stable. With no HVAC, it ranges from 60 in the winter to 76 in the summer- very nearly needing no assistance at all to be livable. Many old houses, particularly in warm climates were only one or two rooms deep to capitalize on breezes. The trend toward very deep houses negates this benefit, and results in dark interior rooms.

I've got spray foamed insulation and use a geothermal heat pump. My system sizing is a lot smaller due to the high insulation than a normal house in this area would be (especially the cooling load as we are in the south).

To be fair, site orientation is tough in city and most modern suburban lots. We had to go with a west facing back yard due to availability. But thankfully the south side trees/house are minimal. House is going to be L shaped with garage on West end. Huge 50 yo Elm on West side also. Ideal - no, but not bad I hope. Planning a covered porch on the west side of the L.

Designing houses for no a/c doesn't quite make sense. Breezes are fine but when humidity is high enough and you have a/c, you won't take advantage of them. So designing for them is wasted effort. Same with high windows and high ceilings. In mixed climates (majority of US population), you still want southern sun and minimize East and West sun.

I'm building in SW FL and right now my windows are in but not my doors. No insulation yet.

Our house has energy efficient, hurricane rated windows and the roof decks will have icynene blown in insulation. We of course will have insulation in the rest of the house and all openings will be sealed. Our AC unit is a variable speed unit and we'll have 3 zones. All lighting will be LED.

First floor of the house is block construction and second floor is 2 x 6 wood construction with Hardie siding over it. First floor will be stucco.

However like Virgil and JDS alluded to, I think the best things we did have nothing to do with modern efficiencies, but in old fashioned siting of the house, etc.

We are building a U shaped house that is only 1 room deep on all sides of the U and we are already seeing the benefits. We sited the house with a north/south orientation with the backyard facing south. All our eaves are 32" wide and we have a 9' deep lanai on the back of the house. Ceilings on the first floor are 10' high.

Because the rooms are only one room deep, it allows for windows on at least two sides in every room. My DH's office, the kitchen/dining room, the great room, the guest bedroom and my studio all allow for cross breezes and even the other day when it was 94 degrees with almost 70% humidity, those rooms with the cross ventilation were quite bearable with the windows open.

While our master bedroom has windows on both the east and south walls, only the window and door on the east wall open. I purposely left off windows on the west wall, to try and keep the bedroom cooler. Being that we're only in the bedroom to sleep, I don't see the lack of extra windows as a problem. Especially since because of my bad allergies, we never sleep with the windows open at night.

Right now there is almost no vegetation around but I imagine that once we plant trees, that too will help with the heating/cooling of the house.