Diminishing Insulation Returns

2010 March 10
by Otto

When I had our house foamed, the spray foam people told me I was an idiot for getting more than 4 inches of foam. Anything more than that was simply a waste of money.

The local brand of closed-cell polyurethane spray foam is Corbond. On their website they have a graph that looks like this:

More Insulation Is Clearly Useless. Or is it?

More Insulation Is Clearly Useless. Or is it?

In an accompanying table of data, they state that the first inch of insulation reduces 72% of the heat loss. By the time you have four inches, adding a fifth inch reduces additional heat loss by only 1%. That inch of foam costs as much as the first inch (and insulates just as well), but is 72 times less effective. So was I an idiot for adding 12 inches of foam to my house? Maybe. Read on.

read more…

Laundry Chute

2010 February 21
by Otto

These days, it’s all the rage to put the washer/dryer near the bedrooms, which usually means an upper floor. From a modern convenience perspective, it makes a lot of sense. From a practical and environmental standpoint it’s a little more questionable.

Putting washing machines in the basement had a very practical reason: every once in a while, they leak. And when it’s on an upper floor, it can create an extraordinary mess. The environmental reason that we didn’t mind keeping the laundry away from the bedrooms is that we hang our laundry outside a good 90% of the time. So even if we’d put the laundry upstairs, we’d still be dragging the hamper full of wet clothes downstairs and outside. Or, given the convenience of everything on the upper floor, perhaps we’d use the dryer more.

Instead, Anne insisted we put in a laundry chute. It’s a fantastic solution to the dirty-clothes-in-the-bedroom problem and it eliminates half of the clothes lugging. Plus, it has the appeal of trap doors and hidden bedrooms: a laundry chute has such a wonderful retro feel that I approved of it on that basis alone.

Once we made sure to have the master bedroom straight above the basement laundry room, we discovered another bonus: the chute goes right by our first floor mudroom, so that when we come back from skiing and you want to unload your smelly socks, you can just dump them into the chute and off they go.

Another unexpected benefit was that the 2′ x 2′ opening that we left for the chute proved to be the perfect chase for our ERV ducts, our solar hot water piping, and the conduit for the wires we ran for our future photovoltaics – all the stuff that runs from the basement up to the attic. In the end, our laundry chute was about about 22′ wide by 18″ deep. Some photos:

the laundry chute opening in the upstairs master bathroom

the laundry chute opening in the upstairs master bathroom

the laundry chute in the mudroom

the laundry chute in the mudroom

in the laundry room in the basement, the chute will empty into a hamper

in the laundry room in the basement, the chute will empty into a hamper

House Update: Walls, Walls, Walls

2010 February 21
by Otto

Things are moving along swiftly at this point: Mark is putting up the outside siding, and the sheetrock is up on the inside. In a week or two, the outside siding should be completely done, and the inside walls should be primed. Here some photos:

front of the house

front of the house

side of the house

side of the house

the view from the southwest corner of the house

the view from the southwest corner of the house

the kitchen, view towards the living room

the kitchen, view towards the living room

From Weather to Climate

2010 February 18
by Otto

One of the disconnects I have with the global warming debate is when scientists talk in the most apocalyptic terms about temperatures rising by one or two degrees. It seems hard to imagine that such a small shift could mean so much, especially when the temperature rises and falls so much throughout the day, and when one January day it’s 60F and the next day the temperature plummets to -25F. Wouldn’t two degrees get lost in the shuffle? And are they measuring in the sun or in the shade?

I was researching Bozeman’s temperature data the other day to understand the weather conditions my house’s heat recovery ventilation system will face. On the Western Regional Climate Center’s website I found a table of data of daily highs and lows in Bozeman, averaged over the years 1971-2000. It was fascinating because the averages smoothed out into an almost perfect graph:

Daily Highs/Lows in Bozeman, MT 1971-2000

Daily Highs/Lows in Bozeman, MT 1971-2000

The graph almost doesn’t quite capture just how smoothly the average temperature rises and falls. For the first two weeks of January, for example, the average lows are 12.2, 12.4, 12.6, 12.8, 12.9, 12.9, 13.0, 13.1, 13.2, 13.3, 13.4, 13.6, 13.8, and 13.9. It continues that way, almost exactly 0.1 degree per day, until three days at the end of July, where the highs are 83.3 and the lows are 52.8, and then the temperature begins to slide back down.

I think of Bozeman weather as unpredictable. It can snow in July and it can be shirtsleeves weather in January. Yet when you average together just 30 years of data, weather has already given way to climate, and suddenly it becomes obvious: when it comes to a warming planet, even one degree has nowhere to hide.

See the complete data here: http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?mtboze

Thermostats

2010 February 15
by Otto

Thermostats. How tough can they be?

We have an in-floor radiant hydronic (ie water running through tubes) system divided into five zones. When I heard that the plumber was planning on five thermostats, one in each zone, that seemed like a lot of hardware on our walls. And then I got it into my mind that, c’mon, this is 2010, I should be able to control the temperature of my house from my cellphone, over the Internet, etc.

Aside from the gee-whiz nature of controlling the temperature from far away, I came up with two scenarios where it might be really useful: 1. You leave home on a trip and forgot to turn down the temperature (or just aren’t sure if you did). 2. The big downside of radiant systems is that they take a long time (several hours) to come to temperature. So I imagined us coming back from a long trip and pulling out our cellphones in the Minneapolis airport and turning on our heat so the house is toasty when we land in Bozeman.

Well. With the goal of having one central thermostat gathering input from five temperature sensors and then connecting the whole thing to the Internet, I quickly waded into a world of extraordinarily expensive systems. You can do absolutely anything, it turns out, but before you know it someone wants to charge you $5,000 for it.

The Internet-controlled BAYweb thermostat

The Internet-controlled BAYweb thermostat

So I started backpedaling. What if I still had five separate thermostats, but each was Internet-controlled? Here I had greater success. I found a great thermostat from BAYweb (check it out) that combines a really nice clean wall mounted unit with full Internet control.

But the Bayweb units are about $200 each. Your basic thermostat is in the $30-40 range. A 5-2 programmable one (ie you can have one programming setting for weekdays and one setting for weekends) are about $50-60. A 7-day programmable one (ie every day can have its own settings) are about $70-80. So the Internet control still adds quite a bit of cost, especially since we need five units.

In the end we decided to go with one of the BAYweb ones for the main floor, and then get 5-2 programmable thermostats for the other four zones.

Whole House Ventilation: ERV and HRV

2010 February 13
by Otto

Ever since we started building our house, I knew I wanted to have mechanical ventilation. The reason for that is that you want to build a house as leak-free as possible in order to conserve heat. The problem with that, though, is that the leaks in a standard house serve the purpose of removing stale air from the house and bringing fresh air in. It’s not just stuffiness that’s the danger, but also moisture control and even your health: radon, carbon monoxide, and VOCs from building supplies all need to be ventilated out to protect the inhabitants.

Mechanical ventilation allows you to control the air flow in and out of the house. But the key to achieving the best of both worlds is a Heat Recovery Ventilator (HRV) or an Energy Recovery Ventilator (ERV).  They both extract the heat (or in the summer, the chill) from the stale air being exhausted and then pre-heat or pre-cool the incoming fresh air. With a transfer of heat efficiency in the 70-90% range, you can have consistently fresh air throughout the home without paying for it on your heating and cooling bills.

Read on to check out all factors involved in the decision:

read more…

Structured Wiring

2010 February 11
by Otto
The stereo/data closet

The stereo/data closet: smurf tubes in the back, blue data bundles on the right, green stereo wires

I have a confession: There’s a good chance I over-wired the house. But I succumbed to the now’s-the-time pressure of realizing that if I ever wanted to put in more wires for either sound, video, or data, then the easiest and cheapest moment is before the drywall goes up. It’s called “structured wiring” because all of the wiring runs back to a central location, as you can see in the photo on the left. (Each one of the wires that goes back to a central location is called a “home run.”)

Here’s what I wired in: data and tv wiring to ten locations and stereo wiring to six locations. Each data/tv wiring location has two RG6 (standard cable video wire) and two Cat5e (ie ethernet internet wire) wires. In addition, to each data/tv location I put in 3/4″ so-called Smurf tubes, which is flexible hose empty except for a pull string. The idea is that in ten years, when we’re all using fiber optics or whatever, you can then pull new wiring through the walls without opening anything up. Just tie the new wire to one end of the string and pull it through the hose.

Read on to see why I went this way.

read more…

House Blower Door Test

2010 February 6
by ottopohl
Mike Mcpherson runs our blower door test

Mike Mcpherson runs our blower door test

There are three ways that energy is transferred: radiation (that’s what makes your face feel warm when the sun is shining on it), thermal (that’s what burns your hand when you touch a hot stove), and convective (like when hot air rises). And here’s the thing about insulation: insulation is tested by how it slows down thermal transfer. When you’ve got a leaky house, then the stated insulation value written on the package when you bought it won’t mean a whole lot.

And all houses leak. Most of them leak a lot.

I don’t think there are any national standards when it comes to how airtight a house has to be built, but recently, a test called the Blower Door Test has become popular. We just did one on our house and learned some remarkable facts. Read on!

read more…

Foaming about Insulation

2010 February 5
by Otto
E.T. Foam Home

E.T. Foam Home

Using sprayed polyurethane foam for insulating is a no-brainer these days. It insulates much better than industry-standard fiberglass batts, both because it simply has higher insulating properties and also since the foam essentially eliminates convective heat loss (ie foam eliminates drafts). Closed-cell foams are also very rigid and contribute to the strength of the house.

Read anything on eco-friendly building, and you’ll find reference to closed-cell foam. It’s great stuff–at least in theory.

The local manufacturer of spray foam is Corbond. It has an R-value of about 6.2/inch. But I was a little suspicious that the guys who spray it in come dressed in hazmat suits. What’s up with that? Read on for some scary statistics.

read more…

Interior Pictures

2010 January 2
by Otto

Here is a gallery of interior shots. I used a wide-angle lens to show the rooms–they seem bigger than they actually are!