Hundreds and hundreds of people visited the Cripes' Round Rock home on the 2011 Cool House Tour on June 5. So many people, we lost track. All we know is that there was a steady stream of curious folks through the house all day long. They came loaded with questions. Many features in a high-performance, green home aren't obvious on the surface -- I mean, the house looks like an ordinary house. But helpful descriptive signs provided by the Cool House Tour organizers pointed out and explained many of the green features in the home. Still, visitors had lots of questions, and we all spent the day meeting and greeting people and answering their questions. It was loads of fun!
Afterwards, we compared notes about the questions we answered. We decided to summarize the FAQs in this blog post.
Questions to the home owner
These are the questions that home owner Karen Cripe answered most often:
Is your electric bill really only $3?
Well no, this month it's a $20+ credit!
How long is the payout on the solar electric system?
We won't know for sure until we've had it longer, but it's looking like seven years.
How much would it cost if you didn't build green? -- and the companion question -- How much did it cost per square foot to build?
Those are hard questions to answer, as it depends more upon how green you want to be and the energy efficiency of your design. For example, having a north/south orientation on the lot helps to cut energy usage. Having windows and overhangs that take advantage of that orientation are examples that help keep energy costs down but don't add to the cost of the house. Also, there is the time factor: An initial outlay -- like a metal roof -- may be higher, but if I don't have to replace it every time there is a hail storm (or every 7-10 years ), the overall cost is actually lower.
Why did you go with concrete floors and aren't they cold in winter?
Love the concrete floors! We went with them because it was cheaper, and I couldn't decide on any other flooring. I figured we would live in the house a while and do something later. It turns out that concrete floors are durable, easy to clean, and nice and cool in summer. They get cold in winter, but since winter lasts only three weeks here in central Texas, I just pull out my collection of slipper socks and I am set.
How did you get away without having a lawn?
No homeowner's association!
Why don't you have a lawn?
By using native plants instead of traditional turf grass, I am using less water, and I have no need for a lawn mower, sprinkler system, or chemicals to make grass grow. Besides, I would rather look at flowers than grass.
If you had it to do over again, what would you do differently?
I would have had the cabinetmaker make custom cabinets for the bathrooms. Other than that, nothing!
Questions to the builder
These are the questions I answered most frequently:
How does the geothermal heat pump system work?
A geothermal heat pump removes heat from the house and transfers it out of the house and into the ground. When answering this question, I talked about the 26 energy efficiency rating (EER), the wells dug in the front flower bed, the free hot water when the air conditioner is running, and the overall low cost of operation. What I learned from the number of times people asked about the geothermal heat pump system is that I need to write a whole blog post explaining how the geothermal system works. I'll do that soon . . . stay tuned.
Tell me about the spray foam insulation.
We used open cell, soy based spray foam insulation. We filled the exterior wall cavities with foam, and we sprayed at least 8" of foam on the roof decking in the attic. Together with the reflective metal roof and energy-efficient windows, the spray foam insulation is a major component of the home's thermal envelope.
What is a thermal envelope?
Think of a thermal envelope as the home's outer shell -- it's designed and built on purpose to keep the hot air out and the conditioned air in. The building science theory behind this is that you don’t let the heat and humidity into the house in the first place, so that you don't have to work hard to get it out.
Was this a remodel?
No, this is a brand-new, built-from-the-ground-up house. There had never been a house on this lot.
How long did it take you to build?
Five months construction time. Years in planning.
Questions to the building designer
Professional building designer Debra Blessman of Select Home Design was on hand, too. She did the architectural design of the home. Debra answered a lot of the same questions that I did, and then she answered these questions from many visitors:
What's the square footage of this house?
It's 1,440 square feet of living space.
Wow, it feels a lot bigger than that.
That's because of the open design. The absence of hallways makes a difference. And the vaulted ceiling in the living room and the coffered ceiling in the master bedroom give a feeling of more space. Additionally, the way the windows and solar tubes are placed allows in lots of light, which enhances the openness. There's just no wasted space in this house.
How did they know how many solar panels to install?
It's calculated based on the anticipated energy load of the home, plus the home owners' goals. For example, they hope to buy an electric car one day, which they would power from the solar panels.
Why aren't there walk-in closets in the bedroom?
The home owners believe walk-in closets are a waste of space. Plus, originally they had planned built-in cabinets in the master bedroom, but we had to cut the custom cabinets to meet their budget goal. So we built reach-in closets with sliding doors.
The solar tubes . . . are those actual light fixtures? What size are they? What's the benefit of solar tubes vs. skylights?
Those are 14" solar tubes. They don't have light fixtures in them, but there are some models that include a light fixture for night-time use. What's cool about these solar tubes is that they have a kind of flexible tubing that allows a lot of flexibility in where you place them in the house and then connect to the roof. There's reflective material in the tubing that increases the light into the house. Compared to traditional skylights, solar tubes bring in light but don't allow heat gain like many skylights do.
Questions in the kitchen
Mary Simon was on hand, too. She's the business manager at Solluna Builders. She manned the front door, greeting visitors and directing them to the people who could answer their questions. She got a lot of questions about the kitchen:
Ooh, the cabinets are beautiful. What kind of wood is that?
These are custom cabinets. The boxes are maple plywood. The faces are alder plywood. There's no formaldehyde in the plywood, and the cabinets are finished using a clear finish with no volatile organic compounds. Kitchen cabinets get a lot of use, and that's why we use plywood. Compared to medium-density fiberboard, plywood is extremely durable. If it gets wet, you just wipe it out.
But there's no pantry.
Sure there is. It's built in -- part of the custom cabinets. Open that door on the left and slide out all the shelves. You can easily reach every inch of every shelf.
What kind of cooktop is that?
It's a magnetic induction cooktop. Heats only the pan, not everything else around it. It's a lot more efficient and doesn't waste energy, and you can control the heat like you can when cooking with gas.
What kind of windows are these?
They're Andersen 100 Series, a composite window designed specifically for our hot climate.
Why are the window screens on the inside?
They're casement windows. See, they crank all the way out so you can get great cross-breezes throughout the house.
If you didn't get your questions answered either here at the house, please give us a call.
We had a great time. The only bad part about having a home on the Cool House Tour is that we didn't get to visit all the other homes. If you missed it, you can still flip through an online version of the guidebook at the Texas Solar Energy Society web site.