Published Tuesday November 4, 2014: Updated January 31, 2016
There is only so much you can do to retrofit an existing home to be energy efficient. For this reason, I am envious of anyone who is building a new home. I say to these people, "You are so very lucky to be in a position to have your home designed for ultra-energy-efficiency from the very beginning, to have it built smart from the concept through completion. From the foundation to the rafters, all without it costing much more than it would otherwise."
If you find yourself in this position of building a new home, don't squander it foolishly by settling for the plain, minimum standard of cookie cutter energy efficiency.
Most homes are quickly thrown up as cheaply as possible, without any regard to long-term energy costs, indirect air pollution, urban sprawl, climate change or long-term savings/value to the home-owner. If the builder can save $200 by following just the minimum rules allowed by the building code, you can count on them doing just that. Why should they intentionally limit their return on investment? They have no incentive to do otherwise. They aren't going to be the ones paying the energy bills for the next 1 to 200 years, so what do they care? If there weren't mandatory, minimum building codes for energy efficiency, the builders wouldn't even do that.
But now is your chance to add some real value to your home. You may never get another chance to make such monumental changes at this price point. It doesn't cost much more to implement energy improvements at this stage but the energy and environmental savings will return you dividends for the life of that home.
Here is a list of things to consider, ranging from "Cheap and Easy" to "Higher Investment Cost".
Cheap and Easy Stuff:
Passive Design: South-facing windows and long roof eves
Design an abundance of south-facing windows (with a very high R-value but still have a high visible transmittance) that can collect an abundance of Winter sunlight. You want windows that allow lots of heat in. This will supplement your heating needs, for free, no matter what your primary heat source is.
Make sure the roof has long roof eves so by mid-spring, they prevent nearly all direct sunlight from entering the home. By summer time, no direct sunlight will enter those windows. In this manner, you can still have a passively lit home but with greatly reduced cooling demands.
Minimize windows on the East, West or North sides. These windows should be very low-E windows (that don't let in/out much heat).
Having unobstructed access to solar energy is your most valuable commodity. Both for solar panels and south-facing windows.
Position the house on the lot so there is unobstructed, south-facing roof space for adding solar panels, (for immediate installation or for later). Make sure that most of the windows are on the south-side so the sun light (and heat) can enter through south-facing windows in the winter time.
Proposed zoning that prevent homes from having access to the sun should not be permitted to be built.
Make sure the house is built very air tight. Seal around any plug socket, light switch or ceiling penetration, (smoke detector, recessed light fixture, etc). Along with air sealing, you may need to add additional ventilation, (see below in the next section).
Spend the money to have R-58 or higher in the attic and R-23 or higher in the walls and high-R-value windows. Just make sure south-facing windows have a high visible transmittance (which also allows in infra-red radiation).
The time has finally come that LED lights look amazing and are super inexpensive. Don't even think about screwing in an incandescent bulb. They belong in the history books. Only install LED lights.
Design the house to minimize the lineal distance from the water heater to the hot-water fixtures. Run the plumbing lines in a strait shot vs. taking the less laborious but longer route of going along a joist and then over.
The hypotenuse is a much shorter distance than routing along both sides.
Double-Insulate the hot water lines early, before they are covered up in walls, floors and ceilings. This won't really save you that much money on energy but will keep the water in the pipes hotter for longer so you won't have to run the tap as often to get hot water.
Additional Conduit and Electrical Circuits:
If you think you might install PV at a later date, run conduit for solar panel installations.
Run two or more double 40 Amp dedicated circuits out to the garage for future EV charging capabilities.
If you don't drive an electric car right now, shame on you!
Quit throwing your money away on gasoline and engine maintenance. While you are at it, write a letter to your future generations begging their forgiveness for all the pollution you are causing and climate change for which you are indirectly contributing, (by not driving electric cars, powered by renewable energy).
Added 1/31/2016: Skip the Foundation Bump-out:
If you are building a house from scratch, keep in mind that every angle change, (where the foundation deviates from a rectangular shape), will increase the cost of your home buy $10,000. If you can't afford solar panels but have a foundation bump-out (two angle changes) in the house design, consider skipping it. That will reduce the total cost of that home by $20,000, sufficient to cover the cost of a large solar array on your home.
Power/Energy Monitor System:
Install a TED (The Energy Detective) or similar whole house monitoring system. Install the TED app on your phone so you can know 'at-a-glance' when excess energy is being wasted in your home and correct it.
Moderately Expensive and Medium Difficulty Stuff:
Spend extra money on a air ventilation/heat exchanger system so you still get fresh air in the home. Going air-tight only to have to ventilate, sounds counter intuitive but it is necessary in order to have a super energy efficient home and still have good indoor air quality.
Drain Water Heat Recovery:
Design the home with a central sewer stack and install a DWHR unit in it. They recover upwards of 75% of the wasted energy that goes down the drain. If the home's design dictates multiple sewer stacks, consider the pros and cons of putting DWHRs in each one. They work the best whenever there is an equal flow of water coming in and going out, like while taking a shower or running the kitchen sink. They don't work as well for baths and clothes washers.
Purchase Only Energy Star Appliances:
Many will pay for themselves in energy savings in only a few years, especially refrigerators and washing machines.
Install double cell window shades or shutters. They will allow in sunlight and when closed will provide more insulation over the windows.
Higher Investment Cost:
PV Solar Panels:
Solar panels will pay for themselves in a few years. They are literally a golden goose that will provide you free energy for LIFE. Burning fossil fuels is a nasty habit, (much like smoking). The sooner we all quit, the better off we will all be. However if you cut a foundation bump-out from the home's plans, that will reduce the total cost of that home by $20,000, sufficient to cover the cost of a large solar array on your home.
Ground Loop Geothermal Heat Pump:
Heating/cooling the home hydronically is the most energy efficient but using air ducts and forced air is also a good way to heat/cool the home with the added benefit of superior air filtration and ventilation.
Installing geothermal during construction will save even more money on installation costs since you won't have to buy a natural gas furnace and central A/C only to be replacing them at a later date.
Installing ground loops at the time of construction vs. after the landscaping is in will save a lot of money. Also, if you plan out your appliances carefully, you may not have to have any natural gas lines ran into the home at all, reducing the cost of building a new home even further.
Running your electric heat pump from renewable energy (like the solar panels on your roof) is the smart, environmentally responsible choice.
Design For Future Climate and Weather Extremes:
Our fossil fuel burning actions indirectly change the Earth's climate, bringing us more severe weather events. These events increase the number of home insurance claims, which in turn dictate that building codes be revised.
Designing for higher wind-speeds, heavier snow loads, colder winters, hotter summers, higher storm surges, more severe drought, insect infestation and higher risks of wild fires are only a few of the changes needed in areas across the country and world.
Consider the costs of designing your home to be more robust than what is dictated by the local building code. You might be surprised that the cost may not be that much more. For example, designing a wooden roof truss to withstand a 150 mph wind vs a 115 mph wind might only increase its manufacturing cost by a few cents per truss.