Karen and Dan are understandably proud of their new home — the first 5-star green-rated home in Round Rock. There’s nothing like it anywhere in the neighborhood.

From the street, it looks like a perfectly ordinary craftsman-style home.

But this home is the result of careful planning, thoughtful design, and deliberate choices that make it super-energy efficient and comfortable.

Karen explained their three-year journey from idea to completion:  “Dan plans to retire early, so he focused on what it costs to own and operate this home — for him, it’s about the bottom line. As for me, I’m an old tree-hugger — I’m more concerned about wise use of the earth’s resources and doing the right thing for the environment. We came at this from different angles, but in the end, we wanted the same result.”

Listen, I could tell you all about the features in this home.  But Dan sat down one day and wrote the following open letter that describes their home — he agreed to let me share it with you. I suggest you go get yourself a cup of tea and sit down for a nice read.

(Don’t miss the customer testimonial. Also, check out the new blog series Zero Energy Home. Dan is tracking and reporting on the home’s energy use.)

What’s Special About This House?  by home owner Dan Cripe

My wife and I have built a new house. We’ve been planning it (and obsessing about it) for quite some time. Not all of the ideas we came up with made it into the house. Some were impractical and others were financially impossible. But quite a few ideas made it through the process (with the help of our designer and builder), and we’re quite proud of our new home.

Our house has a number of special features that make it “green”. It’s a custom home, so the features weren’t arbitrarily selected by a corporate marketing team: they were specified by us, in consultation with the designer (Debra Blessman of Select Home Design) and builder (Wayne Jeansonne) – although some improvements were suggested during construction by the sub-contractors that built it. In fact, almost every sub-contractor suggested at least one improvement that was incorporated in the construction. This is one of the benefits of building a custom home using experienced, talented, and creative people. That’s where every house should start – the people: the ones that will live in it and the ones that will create it.

Some of the special features of our house are visible, but many others are “hidden”, and only show up when we get our utility bills. While planning our new home, we put priority on features that would limit our exposure to long-term increases in energy prices. As we approach retirement, having relatively constant energy costs makes long-term planning much easier.

(Click a photo to enlarge it.)

Thermal Envelope

The energy efficient features of our house begin by keeping the outside air outside, where it belongs. Creating a thermal envelope (the boundary between inside and outside temperatures) that is entirely sealed against air infiltration not only improves energy efficiency, but prevents allergens and other pollutants from entering the house. The thermal envelope was created using spray-foam insulation. This type of insulation expands as it is applied, filling every gap with a barrier that blocks air-flow, as well as insulating the house. It has the additional benefit of making the attic space part of the “inside” of the house (the insulation is applied to the underside of the roof, rather than the top of the ceiling), which provides a better environment for anything stored in the attic.

Geothermal Heat Pump

Our house has a geothermal heat pump, which provides heating, cooling, and a substantial portion of our hot water needs. A heat pump is, in general terms, much like an air-conditioner that can be reversed, moving heat either in or out of the house, as needed. A geothermal heat pump performs the same functions, but instead of exchanging heat with the outside air, it exchanges heat with the ground through buried pipes. By exchanging heat with the ground, which is at a nearly constant temperature all year (about 71° F in the Austin area), the efficiency of the system is significantly improved. In addition, a geothermal heat pump is more durable (fewer moving parts and less seasonal strain) than an air-conditioner.

During the cooling season (which in central Texas is approximately 9 months of the year), the heat pump is moving heat from inside the house into the ground. Rather than waste all of this heat, some of it is used to heat water (which is stored in a standard electric hot-water heater). During the remaining months of the year, the electric water heater produces the necessary hot water for the house[1].

A geothermal heat pump is a relatively expensive investment, that will pay off (financially) after several years. It is, however, one of the few investments in new residential construction that is eligible for a federal tax credit (30% – consult your tax professional).

Energy Exchange Ventilation

Because the thermal envelope completely seals the house from air infiltration, a ventilation system is installed as part of the geothermal heat pump mechanical equipment. This ventilation system exhausts air from the house as it brings fresh air into the house. As it brings the fresh air in, it filters it (removing allergens and other pollutants) and uses the air being exhausted to raise or lower the temperature of the incoming air. This means that the air inside remains fresh, filtered, and comfortable.

Advanced Framing Techniques

Our house was constructed using Advanced Framing Techniques, which spaces the wall studs and ceiling rafters farther apart (among other things). Wider stud spacing uses less wood, leaves more room for insulation and reduces heat conductance through the exterior wall studs. In addition, because Advanced Framing Techniques uses fewer pieces of wood, framing time (and labor costs) are slightly reduced compared to traditional framing techniques.

Finger-Jointed Lumber

Finger-jointed lumber is created using shorter, less desirable pieces of wood that would otherwise have been pulped for use in paper mills or other purposes. By fitting these pieces of wood together, larger pieces of usable lumber can been created. This allows more lumber to be created using fewer trees. While these pieces of lumber are often less “attractive”, they are perfectly suitable for use as framing lumber. Much of the dimensional lumber used in the construction of our house is finger-jointed.

Metal Roof

Metal roofs are more durable (hail resistant), longer lasting, and more energy efficient than most other types of roofing materials. Our house has a raised-seam metal roof composed of Galvalum®. For aesthetic reasons, it has been coated with a colored coating that is specially formulated to resist solar heat gain.

Infill Lot

The location of a home makes a difference, even beyond the personal preferences of the people who will live there. By selecting a lot in an existing neighborhood, it preserves land that would otherwise be taken from agricultural production or natural habitat. The lot already had water, waste water, electricity and other utility services established, which saves substantial time and money (no well, no septic system, etc.).

Existing Trees

One of the reasons we bought our lot is because it included numerous existing trees. Every effort was made to preserve these trees, both during the design and construction stages. Trees not only enhance the beauty of our environment, they help to moderate the extreme heat of our central Texas summers.

Energy Efficient Appliances

Not every appliance in our house is Energy Star labeled – because not all types of appliances are covered by Energy Star. The clothes washer, the dishwasher, and the refrigerator are all Energy Star labeled. While not Energy Star labeled, the oven and cook-top are probably more efficient than their common counterparts. The oven is a convection oven (which cooks food faster) and the cook-top is magnetic induction, which heats the pan, rather than the cook-top, resulting in less wasted heat.

There are other Energy Star products in our home, including ceiling fans, light fixtures – even some of our entertainment system components are Energy Star labeled.

Overhangs

The eaves overhang the windows by 18 inches. This prevents direct sunlight from entering the house during the hottest part of summer days, but allows more light to enter the house when the sun is low in the sky during the winter. While 24 inches would have been better, the constraints of the lot prevented a larger overhang.

Low-E Windows

The windows in our house are designed to reduce the amount of solar heat gain. Special coatings on the glass prevent a substantial portion of the solar energy from entering the house.

Day Lighting

With the large, central open space in the house and the front and back porches shading the windows in this space, we opted to bring in additional daylight through solar tubes, which capture light on the roof and conduct it to the living spaces. This reduces the need for electric lighting during the day, and creates a bright, cheerful living environment.

Low-VOC Paints and Finishes

Volatile Organic Compounds (VOCs) are a significant source of indoor air pollution and are emitted by a wide array of materials. For many years, VOCs were included in paints (in relatively high levels) because they formed the basis of what made paint stick to surfaces. More recently, we’ve come to recognize that VOCs can have serious negative health effects, and paint companies have invested in research to produce paints that contain reduced, or even zero, VOC content. Similar efforts have been made in wood stains, making it possible to eliminate several major sources of indoor air pollutants.

Low-Flow Plumbing Fixtures

Water conservation not only preserves natural resources, it reduces water bills! Our house is equipped with water conserving plumbing fixtures including dual-flush toilets and low-flow shower heads. The dual-flush toilets allow us to use just the right amount of water when flushing.

Xeriscaping

Conserving water outdoors is just as important as conserving water indoors.  Outdoor water conservation starts with plant selection. By using native and well-adapted, drought-tolerant species in the design of the landscaping, less water is needed. The area behind the house, which borders a dry creek, is heavily shaded, and is left in a nearly natural state (some wildflowers have been seeded for additional seasonal color). The  front of the house will be landscaped in consultation with local gardening experts (when weather permits – summer is not the ideal time to establish landscaping in central Texas).

Rainwater Collection

The second step in outdoor water conservation is capturing a supply of water for outdoor use. By storing and using rain-water for landscape use, we’ll be able to keep our plants alive and healthy without running up our water bill[2].

Local Stone

The lovely limestone used in the exterior facing is quarried in central Texas. Using a local product reduces the amount of energy needed to transport it to the construction site. It also means that the company that provides the stone is paying local employees who shop at local stores – which supports the local economy.

CFL/LED Lights

We have fluorescent and LED lights in all of the light fixtures. The quality of fluorescent lights has improved dramatically in recent years. There are many manufacturers producing bulbs that produce a warm, pleasant light (instead of the harsh bluish light previously associated with fluorescent lights). LED lights are just beginning to be available in useful brightnesses (usually accomplished by combining multiple LED lights into a single bulb). We have included  LED lights in some locations where the current limitations of LEDs are not a factor.

Size Matters

Our house is relatively small. We don’t have rooms that don’t fit our lifestyle (we read several of Sarah Suzanka’s “Not So Big House” books with interest), which leaves plenty of room for us and things that matter to us. Having a smaller house reduces the amount (and cost) of materials we use and minimizes energy loss through exterior walls[3]. Less energy loss means that we have a smaller geothermal heat pump – which uses less energy and costs less.

Solar Electricity

My wife and I were a little ambivalent about installing solar panels as part of the initial construction. Of course, the plan has always been to have solar panels, but we thought that we might live in the house for 6-12 months, to get a better idea of how much energy we’re using, so we could size our solar array appropriately. However, solar electricity systems have become more modular, which has allowed us to install a base system that we can expand later. And since our electricity needs are likely to change over the years (my wife insists that she’s going to be driving an all-electric car at some point), having a module solar electric system means we can adapt to those changes without major rework of the system.

Final Word

Our house may not appeal to you, and we have no problem with that. Our house was designed and built for us, with our tastes, goals, needs, priorities, and financial abilities in mind. A house built specifically for you might be very different – and we have no problem with that, either.

This isn’t the only way to be green or the best way to be green. It’s our way, and it’s really only a start. Building green isn’t the same as living green. But at least it’s a step in the right direction.

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[1]Note that since the geothermal heat pump heats the house and produces a significant portion of the hot water, the major consumers of natural gas are not present. The remaining consumers of natural gas would not consume a significant amount. We opted to use all electric appliances, rather than natural gas due to the unreasonable cost of buying a low volume of natural gas (including a significant amount in fees unrelated to the cost of the natural gas itself). In addition, we know that while we can harness solar energy to produce electricity, there’s no practical way we can produce natural gas (please, no jokes about my diet).

[2]We find it curious that as a community we spend a significant mount of money securing, treating, protecting and delivering drinkable water – and then we use a lot of it to flush our toilets and water our lawns.

[3]We’re constantly amazed to see 5000+ square foot homes featured on TV shows about “green” living.