Green Building Up, Even While Construction is Down

Green Building Up, Even While Construction is Down

Posted using ShareThis

Passive Solar Part #4

The benefits of passive solar heating and cooling are as follows:

#1 - The most obvious is a bright, sunny living space that is an absolute pleasure to live in. You will fiind you have more energy year round, even when there is no sun. Some people claim they are less depressed and healthier too. Natrual light (even clouds) is better than light from light bulbs.

#2 - The thermal masss evens out the temperature and makes the home more comfortable to live in.

#3 - A passive solar home cost less to heat, cool and light resulting in lower energy bills forever.

#4 - Passive solar homes produce less carbon emissions.

#5 - The fact you know you are living smart.

Passive Solar Part #3

Passive Cooling. Passive cooling is the idea of cooling without mehancial ventilation. In Minnesota this is less of a concern than passive heating, but still something to take into consideration. Because of the airtightness standards and other building codes, there are some limations to pasive cooling design.

You can have a vaulted ceiling with operable skylights or windows. Another alternative is a thermal chimney, like a three story entryway with operable windows up high.

Exhaust fans that move air from conditioned to unconditioned spaces such as the attic are not allowed by buiding code in Minnesota.

All of our Amaris homes are built with air-to-air exhangers which exchanges and conditions fresh air and can help cool down a well insulated home without air conditioning.

Landscaping is one other strategy that can contribute to passive cooling techniques. Good old fashioned trees are a way to shade a home in the summer.

Passive Solar Part #2

Yesterday we talked about direct gain passive solar. There are other passive solar design methods such as indirect gain or isolated passive solar. These systems are not as practical and are more expensive to implement. Other systems that incorporate convection air flow from conditioned to uncoditioned spaces are not allowed by many current building or fire codes.  For this reason, we are not going to spend a bunch of time on the passsive systems not likley to be implemented.

Isolated Passive Solar. An isolated passive solar system is a one or two story solar sunroom that is attached to the south facing portion of the home. This method is a very expensive, less efficent way to implement passive solar for a new home, unless you happen to just want a one or two story sunroom. The solar sunroom may be an excellent way to modify an existing structure that is south facing but was not solar designed.

Solar sunrooms are great for growing plants and vegetables. Just like with the direct gain passive solar, the isolated passive solar utilizes thermal mass to store heat as well. In addition to tile or brick, the thermal mass might include a small hot tub, pool or spool.

Windows can be opend on both floors to create the circulation. Hot air rises and will come into the bedrooms. Cold air falls down to the first floor and out the window. In an extreme cold climate like Minnesota, this will only work in the spring and fall.

Passive Solar Part #1

Passive solar is a big part of a Net Zero Energy home. There are various passive solar systems. Direct gain passive solar is the easiest and cheapest to implement. Direct gain solar is a system where the living space is the solar collector, heat absorber and distribution system. There are two parts to this type design. South facing glass and thermal mass.

South Facing Glass. We recomend the rear of the home be south facing because it natrually has the most amount of windows in most modern home designs. The goal (and requirement) is to get southern exposure into as many of the everyday living spaces. From a design perspective this will take exta planning.

South facing windows need to be screened from (high) summer sun by overhangs, roofs or other methods, but they also need to allow the (low) winter sun fully into the home during heating season. South facing windows are typically taller than standard windows to allow passive solar to reach the full depth of the entire room. Passive solar designs also tend to elongate the home on the east/west access, thereby shorting the north/south access.

As mentioned in other posts, the most used rooms (e.g. family room, kitchem master bedroom, etc) should be south facing. Unused rooms (e.g. dining rooms, spare bedroooms, laundry room, etc) should be located to the north. An open floor plan optimizes passive solar design.

Northern Glass. Because we live in extreme northern climate, north glass should be eliminated if at all possible. If north glass is used, it should be minimised and install high "U" value windows. If budget is an issue, storm windows on north facing glass is a way to accompish the same thing.

East/West Glass. East/west glass should also be minimized too. The "baking" affect is not as great in Minnesota, but east/west glass can cause rooms to overheat in the summer. We like to use transom or other accent windows on the east/west access.

Skylights. Some older passive solar designs used skylights, but it is my belief that skylights should never be used in a direct gain solar design. You will bake the house in the summer defeating the purpose of a true passive design. Also, if you live in the North, you will eventually have a leak.

Thermal Mass. The passive design requires a thermal mass to absorb the heat generated by sunlight and then releases it back into the room at night. Thermal mass includes the floor and wall surfaces covered by certain darker ceramic tile, brick, etc. Becuase the thermal mass absorbs the heat during the day, the room temperature is tempered during the day.

There are a number of calcualtions to consider for thermal mass, most of it boring stuff. The amount of masonry per sqaure foot of south facing glass. The amount of south facing glass as a percentage of square footage and so on. Suffice it to say that although a passive solar design does not need to look different than most construction, it is scientifcally calculated and built; it doesn't just happen by accident.

Net Zero Energy Homes Part #5

When planning a Net Zero Energy Home, here are some suggestions:

1 - The garage should face North to shield the house from North winter winds. The garage should be fully insulated with insulated garage doors, but not heated.

2 - It is best to have the gable ends facing east and west. The angled portion of the roof should face north and south. The north winds will flow over the roof easier.

3 - The rooms imediately adjacent to north facing walls should be things like closets, laundry room, pantry and storage rooms. These rooms can be colder in winter and warmer in summer and will not affect the comfort of living in the home.

4 - There should be no windows facing North; ha-ha that never happens. At least minimize the amount of North facing windows. Use tripple pain windows for North facing windows if budget will allow (be careful to match color and style).

5 - Consider an enclosed front porch for the remainder of the front elevation (mius the garage). It functions in the same way the garage does, serving to shield the house from North winds.

6 - Whenever possible, locate closets and other such non-active rooms first to the North and then to the east and west walls. Any North facing rooms should be rooms like dining rooms or spair bedrooms, which are used the least often.


7 - Windows to the South should be tall enough to allow full sun into the house during winter (e.g. passive heat). The south windows should also be shaded for summer sun to keep sun out.

8 - Don't build bigger than you need to. Carefully plan your building. Each extra one sqaure foot os space cost dollars to heat, cool and light.

10 - Don't canteliver of build over the garage. These areas are very hard and expensive to insulate properly and contribute to heat loss in winter and heat gain in the summer.

Net Zero Energy Homes Part #4

The Amaris Company wall system starts with the DOW Structural Insulated Sheathing product on the entire exterior which provides an R5.5 insulation factor and a complete exterior air and moisture barrier. Because the DOW SIS wraps the entire exterior there is no wood to wood connections to the inside of the house and therefore no thermal bridging. Thermal bridging is when cold air conducts through wall studs and sheathing were no insulation is installed. You may have seen vertical lines on the sides of houses when driving through your subdivision in winter.
In our standard green homes, Amaris Company sprays 3" of closed cell insulation providing an R-21 insulation factor. The closed cell insulation also provides a complete air barrier. Air provides and "R" value of 5.0 when it is not moving. Because the DOW SIS and closed cell insulation provide superior insulation factors and air penetration barriers, we do not believe it is necessary to fill the entire 2 x 6 wall cavity.

Ceiling insulation is very important. Building code in Minnesota requires R-38 in our area. The Amaris Company system includes 1" closed cell insulation (R-7) over the ceiling deck and then cellulose insulation to an R-60. The closed cell insulation provides a complete air barrier.

Insulated foundations is also very important. We insulate the foundation walls and floor to an R-20.

Net Zero Energy Homes Part #3

Most people prefer to own a home that looks like a "normal" building structure. However, be aware there are a number of alternative structures that are well suited for a Net Zero Energy Home. For example, in the 1980's during the energy crisis, earth and dome homes began popping up around the country. They have proven to be very energy efficient but not very popular.

More recently SIP's (Structured Insulated Panels) and ICF's (Insulated Concrete Forms) have also become visible in the marketplace. SIP's and ICF's look like normal structures but tend to be cost prohibitive for most families.

All of these alternative building structures work well. Each of them have advantages and disadvantages. At Amaris, we have developed what we believe is the best, high-performance, yet affordable wall system that can be utilized in traditional architecture.

Net Zero Energy Homes Part #2

Most people naturally jump to the production side of the equation when thinking about a Net Zero Energy Home. It is fun to think about producing energy via solar or wind or other high-tech method. The truth is building and owning a Net Zero Energy Home is mostly about the consumption side of the equation.
To make a Nert Zero Energy Home affordable, every effort must be made to build a structure that will not need energy in the first place. This encompasses everything from the lot you chose, to the type of structure you choose, to the placement of the structure on the lot, to the energy efficency of the structure, to the equipment that uses energy, to the equipment that produces energy.

A lot that is going to be a Net Zero Energy Home will need to be suitable for solar and/or a wind turbine. Most city and suburban locations do not currently allow wind turbines. This may change over time, but it is important to check with City officials prior to purchasing the lot.

Lots sutiable for solar typically will be south facing and will not be impeded by trees. If there are trees on the lot, an architect using computer generated programs should be able to place the house on the lot and verify the suitable of solar prior to purchasing this lot.

Also, I recomend checking with the utility company prior to purchasing the lot regarding rebates and incentives, requriements and potential road blocks.

Net Zero Energy Homes Part #1

I met with some potential clients this weekend who are interested in building a Net Zero Energy Home.
A Net Zero Energy Home is a home that is built using extremely energy-efficent construction techniques and utilizes solar, wind, and other equipment that returns energy to the power grid to meet your yearly annual energy needs.

A federal law was passed in 1991 which requires utility companies to allow consumers to put energy into the pwer grid and then use it again later (e.g. "Net Energy"). In Minnesota the state legsilature passed a law that requires utility companies to pay consumers the retail price of the elctricity at the time is goes in the grid. If you put the energy into the grid during the day when electricity is at a premium and then buy it back in the evening when you are home from work, you can actually purchase more power at the same net price.  The goal at the end of the year is to pay a energy bill of zero (e.g. Net Zero Energy Bills), not to be confused with a Net Zero Energy Home. A Net Zero Energy Home actually produces the amount of energy it will use over the course of a year.

Spring Is In The Air

Wow.....I can't believe I haven't been able to keep up with the blog these last few weeks. Sorry about that. It all started with a well deserved one week vacation to Arizona and then two weekends in a row working the St. Paul and Minneapolis Home and Garden Shows.

The days are getting warmer and snow is melting. SPRING IS DEFINATELY IN THE AIR. The best evidence of this is our telephone is starting to ring with people who are starting to think about building and remodeling. The Home and Garden Show in Minneapolis was well attended and it appeared that many people are considering making improvements to their homes.

What was discouraging is that so few people are unaware of "green" building and remodeling techniques and are fairly indifferent to the idea. It is hard to understand why people would not be concerned about mold, premature rotting and water intrusion; or why people would not want to increase energy and water efficiency which saves on utility bills for as long as they stay in the home; or why people would not be concerned about the durability of the home, or why people would not be concerned about the how safe the home is; or how comfortable the home is. Booths selling the "eye candy" products were filled with people. It seems clear people prefer vanity over sanity and the facade is more important than what is behind it. We are a Disney World generation for sure. Yes, people want granite counter-tops, gourmet kitchens, hi-tech a/v systems, fancy bathroom tiles and the like.

There are also many companies claiming they are “green” builders or product suppliers but when you ask them a pertinent question, they can’t even answer the question. People are deceived, which only makes being a "green" builder all the more difficult.

I am not discouraged though; there is small but growing group of people who “get it”. They are educated and know what is possible. Are you one of them?