We're In HOT Water

No we're not in trouble - at least as far as we know, but we do have a lot of hot water at our fingertips thanks to our solar hot water system. I've even had to adjust the balance on the system because we're making so much of it.
In response to a couple of requests, I'll do a bit more explanation of our solar thermal domestic hot water system. That's quite a mouthful for something that makes hot water for our household use.

Here's how it works:

Solar Collectors are mounted on the roof. Piping runs through the solar collectors and down into a storage tank. Inside the piping is a glycol solution that picks up heat when running through the solar panels and sheds heat when it gets to the storage tank (The pipes are full of hot glycol. The hot pipes make the water in the tank hot). The hot water, when it's hot enough, goes directly to our showers, baths, sinks, etc. If it's not, it goes to our back up water heater (the water heater that came with the house) and gets brought up to temperature. Sounds so simple you'd think a code inspector would understand it right? Well, I suppose that's another story for another time.

Right now, our water is plenty hot. This winter, I expect the water heater will have a little work to do, though not nearly as much as it's had to do in the past.

Our solar panels are Solar Skies SS-32 Flat Plate Collectors, 4'x8' mounted at 45 degrees. We mounted them "landscape" rather than the traditional "portrait" to reduce their profile. Mario of Best Power International custom designed this system and improved the way the piping works in this type of installation. We're getting higher efficiencies and a much sleeker aesthetic. It's pretty dang sexy.
The panels have anodized aluminum frames, low iron textured glass and a high efficient nickel-chrome selective surface copper absorber. All of these things increase solar energy transmission - making them more efficient.

Our Solar storage tank is an 80 gallon Rheem HE Soleraide tank (in addition to our 40 gallon water heater - so we have 120 gallons of superbeautifulandwonderful hot water when we want it.

The system also has an expansion tank, a controller, sensors and a Caleffi Pump assembly.

The pump and valve system essentially manages and controls water temperature. It brings in cold water when it needs to or sends the warm water to be made hotter in the existing water heater. (If the existing water heater hadn't been a fairly new, energy efficient model - we'd have done a different kind of combination system.)

Can Air Conditioning be Green?

So we’re starting to feel a little more at home now that we have gotten the first few scratches in the new floor and have little handprints on the walls and windows. When we first moved in, it felt like we were vacationing in someone else’s house. I think this is because we were cautious about all the new floors and walls- being careful not to dent, ding or scratch anything. We still are being cautious, but the reality of having 3 kids is setting in and we realize at some point, we’re just going to have to settle for the “patina” that comes with children. I have no idea how the new wood floor is getting scratched!

One thing we’ve gotten a few questions on the last week is how can our house be ‘green” and still have air conditioning? Good question. We’ve never lived in a house with built-in air conditioning until now. We’ve had window AC units before, but never the full meal deal. So, here’s the scoop on our AC:
- The existing house had a new AC unit, sized for 2 tons. We didn’t want to toss that equipment and refrigerant in the landfill and so decided to keep it in use.
- The existing AC unit isn’t large enough to provide cooling for the entire house by normal standards, so our mechanical contractor initially recommended that we reuse that AC unit, plus add another 2 ton unit. We resisted, because we don’t like the inside air too cool in the summer- we just wanted enough to take out the humidity and keep it comfortable.
- We settled on reusing the existing AC unit and only air conditioning the upper floor (where the bedrooms are). We have an opening between the first floor and second floors which acts as a natural convection chimney, helping to move air around the house through passive ventilation. The 2-story space allows the cool air to fall down to the first floor and keep it cool as well. By doing so, the ac unit works a bit harder and stays on longer when it does run – which actually helps improve its efficiency. We also tied the return air ductwork serving the two floors together to help balance the system.

- Because we have such good insulation in the walls and roof, and good air sealing, along with great windows the house stays naturally cooler. When it cools down, it tends to stay cool. It’s the same concept as the coolers you carry to your picnic – we keep the cool air in and the hot air out. It helps that our living spaces are facing north and we have exterior sunshade above the windows on the south.
- At night, when it isn’t too humid, we open up the windows and let the cool air in. Every room has windows on at least 2 sides, so it’s easy to get cross-ventilation.
- We keep the thermostat at 78 degrees, so the AC doesn’t have to run much. In the winter, we’ll keep the temperature set at 65 degrees)

It’s not such a bad thing – actually being cool enough to sleep. We’re better rested and happier people if we haven’t stayed up all night sweating in a hotbox.

A Roof Full of Energy

We've spent the last few weeks waiting for Xcel energy to come and trench in new electrical service to the house from the alley. We wanted to replace the old overhead wires (they tend to get burned when your neighbors garages start on fire or come down in storms) with buried cable. Even though we've been on the schedule - they never seemed to make it to our house to do the work. This has cause multiple delays and rescheduling of things and has generally been pretty irksome.



The crew of 6 showed up today - 5 guys to watch 1 work - and started in on the task, their brand new trucks at the ready. I tell you all of this just because in my heart, though I have been completely aggravated about their adherence to schedule - I am secretly amused because I know that in a few days we will be selling them energy that we've created on our rooftop through our solar pv array.




A view of the solar thermal panels behind the solar pv panels. The white roof membrane helps keep our house cooler in the summer by reflecting unwanted solar radiation away from the house. This will get covered up by our green roof system this fall.

With the help of Mario Monesterio form Best Power International, we've created a little energy garden on the rooftop. We have both a solar thermal system for making hot water for the domestic water needs of the house (washing dishes, clothes and bodies), and a solar photovoltaic (pv) system to make electricity. Whenever the sun is shining , we'll make electricity for our own use. And, because we decided to tie it into the utility grid, whatever we're not using we'll be selling back to the utility company and watch our meter spin backwards.

We have the pv system also connected to a battery back-up system so that we can continue to have power even if the power lines go down in a big storm (not ours of course, because they're buried). This is a sweet little system that even Mario is jealous of. He must be at least a little proud of it because he brought a few folks by the house yesterday to look at it. Both the solar thermal and solar pv systems have a lot of nice gizmos and features that allow us to do different things including data tracking and energy production, use and efficiency monitoring.

Okay - so how much did we pay for these systems?

The solar thermal system (2 panel) was just over $6,000.00 (not accounting for federal tax credits) and features a payback period of about 12-14 years.


Leon the builder and Mario the solar guy discussing where to buy white socks.

The solar pv system (1.5 KW) cost just over $16,000 (not accounting for State tax rebate of $3,000 and the additional federal tax credits - roughly another $2,000). In the end, the pv system should pay for itself in about 16 years -perhaps sooner if energy prices continue to climb. Solar energy is still more expensive per kwh than buying regular old electricity from the coal burning plant down the road - but with better social and environmental karma.

Lighting Selections

It is the 2nd week in April and winter is STILL rearing its ugly head. We were at the house meeting a reporter from the Pioneer Press when the winds started blowing and snow started falling. Now (11 pm), we're getting a weird combination of thunder, lightning, snow and sleet. Old Man Winter is like some tortured soul that won't be put to rest without a fight.

So, the word is getting out on EcoDEEP Haus. There was an article in the local newspaper, the Highland Villager a few weeks back. The green resource website JetsonGreen, http://www.jetsongreen.com/ recently featured the project and the St. Paul Pioneer Press will have an article in their April 21 issue. Also, look for us in Architecture MN magazine May issue.

As we were at the house on this gray, blizzardy April day (something is just wrong about the word blizzard and April in the same sentence), we noticed how light-filled this house is, even in these adverse conditions. Even when we’ve been at the house in the early evening, we’ve been amazed by how well-lit the spaces are. There is no lighting or power in place yet but soon they will begin fixture installation.

Picking out lighting fixtures can be a daunting task. The lighting budget can very quickly get out of control, as something like a dining room fixture can cost anywhere from $150 to thousands and more. (And it turns out we usually prefer the most expensive ones! Go figure.) We started out with a very modest lighting budget, so we’re doing the best we can with what we have. But it’s very difficult to judge quality from a small picture viewed on the web!

In addition to the budget constraint, the MN Green Star program we are following has some tough guidelines on lighting. They give credit for use of CFLs, halogens and LEDs. They also give points for “no recessed lights in insulated ceilings”. This requirement made lighting selections difficult for some spaces on the upper floor of the house- namely the bathrooms and hallways where you’d usually see recessed can fixtures.

We found this fixture, which is a halogen fixture by WAC, and used it in a variety of ways. It’s adjustable, comes in several colors of shades and can either be wall or ceiling mounted. We used it above the kitchen sink/counter along the exterior wall, in the upper floor corridor ceiling, on the walls of the “hole” (opening between 2nd and 1st floor) and at the bridge walkway ceiling. We were also going to use it above the bathtub- but Mr. Code Official said no to that. http://www.waclighting.com/USA/products/?categoryid=218&productid=950

This fixture will be used in the bathroom ceilings as general illumination. There’s a fine line between too fussy and clean/modern fixtures. We’re hoping this one will pass muster when we see it in real life.

http://www.formplusfunction.com/12333.htm

This is what we selected for the bathroom vanities. It’s a halogen display light with an adjustable arm. We have one of these in our attic space and love the clean, industrial look of it. The bathroom vanity light might be the most difficult light fixture to select. Most of the options available are way too fussy and ornamental for us.
http://www.techlighting.com/default.asp?page=products&subpage=systemselect&sysid=7







This simple George Kovacs ceiling fixture will be used for all the bedroom ceilings. In this case (and many other fixtures in the house), we order them with standard lamping, but will use CFLs.
http://www.allmodernlighting.com/George-Kovacs-by-Minka-P852-044-gkv1442.html










This is another George Kovacs fixture for use over the dining room table. This one will set you back about $200.
http://www.allmodernlighting.com/asp/print_detail.asp?sku=gkv1368












This is the pendant by Vado for the Kitchen countertop. Simple and won’t compete with out Apple Martini Countertop!
http://www.lightinguniverse.com/products/view.aspx?sku=771845&linkLoc=









This fixture is for the exterior overhead soffits at the front and back door. It’s a standard fixture that's been around for years.





You can get it at a number of places. Here is one:









http://www.lampclick.com/lighting/item/9103-20296/13/Access_Lighting_Nauticus_Contemporary_Outdoor_Bulkhead_Wall_Sconce.html

Insulation - A Home's Long Underwear

Just as the weather is turning slightly warmer - we're able to insulate our house. This is a big deal -as strange as it may sound, it is one of the most important aspects of the house. A well insulated and well sealed house is far more energy efficient and comfortable than homes that are poorly insulated. Insulation remains a critically important component of any green building—whether residential or commercial. No matter the type of insulation used, if it is used appropriately, its environmental benefits over a building’s life will almost certainly far outweigh any negatives—and dwarf any environmental differences among the alternative materials.

Our insulation contractor - Homeco Insulation - was on site last week preparing for and then installing the insulation in the walls, roof decks, rim joists and attic spaces.

We've used a few different approaches to insulation in this house. The common denominator being spray foam insulation. This insulation type is an expanding insulation that seals gaps, cracks and joints within the cavity it's filling, hardens into a strong shell and acts as its own vapor barrier. It carries a true R Value of R6 per inch and so we're able to achieve a wall system of R28 (closer to R30 if we count sheathing and air films, etc) in our walls. The walls will actually perform at that level too - unlike many fiberglass insulation installs that perform well below their label of R19. In order to combat the effect of potential thermal bridging through the studs -we used the dri-side clip system and air space behind our siding (R2). Another way to do this would be to install rigid insulation sheathing (or to have used structural insulated panels) but our builder wasn't comfortable with that approach - given that the hardie plank siding is heavy and he worried about screw length and weight and the ravages of time.

In the new walls (and accessible existing walls), we used a closed cell spray foam insulation at all wall cavities and rim joists (read more about the differing types of insulation down below) and in the existing walls we cored from the exterior, filled the cavities with dense pack cellulose and used a bio-based expanding foam to plug the holes.

A view of the insulation in the walls and roof deck. Note the yellow post it note I've left the insulators where I think the fill is a bit too shallow. Just like proofreading a document, you need to walk back through an installation after it's complete to make sure everything is filled just so because the foam expands during installation and takes a bit of time to cure.

On the roof decks and ceiling - we had originally planned to use 8" of spray foam at the bottom of the roof deck to get an R50+ rating (the higher the R value the better). However, we needed to trim a little $$ from our budget and so worked with Homeco Insulators to come up with a sensible alternative without compromising quality or performance. Because our roof trusses are 14" deep, and have no light fixtures in our insulated ceilings, we had plenty of space to fill. We used 2" of spray foam against the roof deck and then did a "net and blow" installation of 12" of dense fiberglass fill (virgin wool - Insulsafe SP) with a poly sheet vapor barrier.There is also varying thicknesses of rigid insulation on top of the roof deck (and below the fully adhered roof membrane) to help direct water flow to the roof drains. The combination of these systems produces an R value of R50+ in the roof at less cost. At soffit areas and overhangs, we sprayed 10" of spray foam for and R60 rating. Working with our insulators from start to finish was great - they offered the best solutions for the challenges of this house and did a top-notch job. The 3rd party energy modeler and testing agent for the Greenstar and Energy Star program gave the installation an "A".

A look at the "net and blow" fiberglass installation below the roof decks. Note how all seams and penetrations (electrical boxes and bathroom fans) are taped and sealed. The fiberglass will be pushed up against the spray foam above by the gypboard at the ceilings.

In the attic space below the existing gable roof, we added vents, air chutes and enough of the same fiberglass insulation used elsewhere to achieve R50+.

On our foundation walls and under the new slabs, we used several inches of rigid, high r value XPS insulation to keep heat from migrating to the earth through our floors. This helps keep our feet warmer in the winter.

Not bored yet? Here are some brief summary notes about some of the different types of insulation available today. [Source - Environmental Building Newsletter V14.1]

To really understand insulation materials kind and gentle reader, you have to understand the basics of heat flow. As you will no doubt remember from your high school physics class, there are three primary mechanisms of heat flow: conduction, convection, and radiation. Conduction is the movement of heat from direct contact, usually through solid matter—the handle of a hot frying pan conducting its heat to your hand, for example—but thermal conduction also occurs with liquids and gases (think boiling water or oil splattering on your hands at the stovetop).
Convection is the transfer of heat in liquids and gases by the movement of those molecules from one place to another. As air is warmed, it expands, becomes more buoyant, and rises—a process called natural convection. Forced convection is the distribution of warm air by use of a fan or air handler.
Finally, radiation is the transfer of heat from one body to another via the propagation of electromagnetic waves. Heat moves from warmth to cold. When you sit in front of a fireplace and look into the fire, your face is warmed by the radiant transfer of energy from that heat source to your face. That radiant energy is not affected by air currents - you can still get sunburned on the beach even when there is a breeze. Most insulation materials function by slowing the conductive flow of heat. Materials with low thermal conductivity more effectively block heat flow than materials with high thermal conductivity. The R-value of an insulation material measures its resistance to heat flow.

Note that air leakage is a type of convection. Air leakage allows conditioned air to leak out of a building and unconditioned air to leak in—bypassing the insulated portions of the envelope. In older homes air leakage around windows, through poorly fitting doors, and across poorly detailed walls can sometimes account for over half of the total wintertime heat loss! Air leakage can also occur through an insulation material, which can reduce that material’s effective R-value. Loose-fill fiberglass, for example, usually allows more airflow than does cellulose insulation.

Fiberglass: The most prevalent type of insulation in North America, fiberglass is produced from silica sand with various additives, including boron. Most fiberglass also contains a fairly high percentage of recycled glass. Scratchy and almost never installed correctly, fiberglass batt insulation for wall cavities is pretty low on my list of acceptable insulation products. The dense pack fiberglass fill is much better- especially when cavities can be sealed in another way- either by caulking or spray foaming.

Cellulose: Offering better R Values than fiberglass and without the scratchiness, Cellulose insulation is made primarily from post-consumer recycled newspaper, with up to 20% ammonium sulfate and/or borate flame retardants.

Mineral Wool: For cavity-fill and attic applications, rock wool and slag wool are similar to fiberglass in look and feel, though the density is greater and the sound control better. The fire resistance of mineral wool is also significantly better than that of fiberglass, because of both the higher density and the significantly higher temperatures required for melting. Mineral wool can also come in the form of rigid board insulation - especially useful for below grade installations.

Cotton Insulation. Cotton insulation is batt insulation made from pre-consumer recycled denim scrap. The cotton or cotton-polyester fibers are treated with a nonhalogenated flame retardant. The big plus here is that it is of high recycled content and doesn't scratch your lungs eyes or skin when installing it. It feels like your favorite old pair of jeans.

Spray Foam Insulation:

Closed-cell polyurethane - Closed-cell, high-density polyurethane is a very good performer owing to the low-conductivity gas in the cellular structure. It is used both for cavity installation and as an insulating roofing material, which is typically referred to as spray polyurethane foam or SPF. The closed-cell structure gives SPF structural properties. There should be no significant impact on R-value with the shift to non-ozone-depleting HFC-245fa blowing agent (ozone depletion potential = zero) , which is becoming the industry standard. Polyurethane also exhibits superb adhesive properties and good compressive strength.

Open-cell polyurethane. Open-cell polyurethane is most commonly installed into open cavities, though formulations are available for filling closed cavities from holes at the top. This is a nonstructural foam, though these materials seal very well, and their flexibility allows for some movement of the framing materials as shrinkage and expansion occur. These properties make them very effective insulation materials for older buildings. Some open cell polyurethanes are made from bio-based materials such as soy beans. Think of fluffy tofu.

Both closed-cell and open-cell polyurethane must be installed by trained professionals. Special care is required to ensure the safety of insulation installers working with these materials; other people should not be in the space while polyurethane insulation is being installed. Once cured, polyurethane insulation is considered by most IAQ experts to be quite inert. Closed cell offers better R values than does open cell.

Okay?

Windows Are In

After a bit of delay, the Inline fiberglass windows were almost all installed on Friday. The front door has also been relocated. We went with white windows to match the existing windows. The existing windows were replaced relatively recently, so we decided to keep them. It will be interesting to see how the new windows measure against the existing, as far as heat loss.

Mazzy and Cormac are hanging out in Kerstin's bedroom. I love the great window wall and balcony! As much as we hate to think about window treatments, we just might have to have something, otherwise our house might be a very popular tourist attraction.


This is the corner window at the living room. Because the windows are installed from the exterior, this space is only accessible now to those who can squeeze through a crack about 10" wide. (Thus, this photo was taken by Mazzy) I imagine that Michlitsch Brothers will be removing the corner of the existing house on Monday to open up this space to the existing house spaces. They were waiting for more enclosure on the new spaces before exposing all the existing spaces to this great MN weather.


View towards kitchen windows from new dining room. The wall the left is the existing wall that will be removed. The back left corner is the 10" gap that Mazzy fit through.

Okay - I have to add a bit more information to this post to make it more than a newsflash.

If you read one of our earlier blogposts about window selection, you know that we spent quite a bit of time researching window options, manufacturers and installers. After we selected Inline Fiberglass, our work continued. We spent time working with the glazing gurus at Inline to select the right type of glass and low-e coatings for each of the windows - depending on orientation, function, amount of shading and desired performance characteristics. In general, Low-E coatings come in 2 types, hard coat and soft coat. They each do different things, or rather, the same thing differently, relative to improving energy performance of the windows. On the North facing glass we are not concerned about solar heat gain but rather are concerned about heat loss. So we have two soft coat low-e coatings one of which is positioned to reflect heat back into the interior of the house. On the East and South facing windows, we are trying to use the windows for some passive solar heat gain collection in the winter- and the windows are well protected/shaded in the summer, so we are using hard coat low-e coatings (2 coats on the east and 1 on the south). On the west facing windows, we are using 2 soft coat low-e coatings (but differently than on the North) in order to reflect heat away from to glass as it is unprotected and the sun angle is generally very low in the evenings. This all means that we will have excellent U Values - in the .17 to .21 range for the entire assembly, not just center of glass - depending on orientation and if they are fixed or operable. This will dramatically improve the windows' performance - especially in tough Minnesota winters. They would have done so already - just with standard coatings available, but working with Inline to spectrally select the glazing and low-e coatings helped to squeeze all the energy savings we can possibly get out of the windows. This is a no-brainer. We're paying for the windows anyway, we don't have to pay extra for a hard coat vs a soft coat, so we might as well design the glass to work as well as it can - helping us to be as energy efficient as possible. You should all try that too.

Flat Roof, Green Roof, Metal Roof, Woof Woof!

Well folks - at long last, our roof is on! We were able to get it installed just before the snow fell last week and so now our house is nearly fully enclosed.
Here's a little information on our roof system. In keeping with our modern aesthetic, we elected to use a flat roof. Many people are afraid of flat roofs in climates with lots of snow or heavy precipitation - but there's really no reason to be. Look at all the commercial buildings out there that have - guess what - flat roofs. You just don't see them on houses very often.



There are a number of reasons why flat roofs make sense.

• First of all, the roof isn't actually flat. The top chords of our trusses slope slightly (1/4" per foot) to ensure proper drainage away from the center of the roof area and is directed to the roof drains and downspouts with some tapered roof insulation and "crickets" - built up areas of the roof to direct water flow. Leaky roofs are usually due to poor installation rather than poor design.


• Flat roofs are usually better insulated than pitched or gabled roofs. This leads to a reduction in the heating and cooling needs of the house.


• Flat roofs also usually last longer - and so have a lower embodied energy that their traditional gabled counterparts. They also are less likely to be damaged in a hailstorm.

Our white membrane roof during installation on a cold day.

We've elected to use a fully adhered TPO white reflective membrane from Firestone (Ultraply TPO 60 mil). It features a very high solar reflectance index - which means it is reflecting heat away from the house and that will lower our cooling needs in the summer. (The ultraply product comes with an Energy Star rating - and so we'll get a nice little tax rebate as well) Shouldn't we want our rooftop to absorb heat in the winter? Not really, because since our house is going to be very well insulated (14" of spray foam and fiberglass) it wouldn't have as much of an impact in the winter. The white membrane also will reflect light back up onto the solar panels - slightly improving their performance.

We've designed the roof to carry the weight of a green vegetated roof system - even when the soil and plant materials is fully saturated with water. We are still in the process of selecting the green roof manufacturer but we can tell you that it will be an interlocking grid and tray system that can go right over the top of our membrane - no issues. The system will be pre-planted with native plant species appropriate to our microclimate and site exposure. We expect to have about 4" of soil depth and grow wildflowers, grasses and sedums in our trays. We're looking forward to how this roof system will help absorb and manage stormwater, suck up CO2 from atmosphere., sequester carbon, provide habitat for butterflies, improve air quality, further reduce the temperature of the roof, improve acoustics and insulation value and in general be a pretty darn cool thing.

This is how our green roof and solar panels should look when complete!

A small area of rooftop on the existing house will remain as a gable roof - rather than using asphalt shingles here, we've decided to use a standing seam metal (steel) roof on this area of the house. The paint finish on the metal roof is also energy star rated and comes with a pretty darn good warranty. 45 and 50 year warranties are pretty typical for metal roofs and very many last quite a bit longer than that. By the time our roofs need to be replaced, I hope to be well in my cups. Happiness is never having to reshingle your house.