Promoting sustainable shelter in Alaska
From The Wall Street Journal:
For homebuyers, green is fast becoming a priority — whether it’s because they want to reduce their energy costs, minimize their carbon footprint or improve indoor air quality.
Here are 10 questions that prospective buyers or renters ought to ask to find out how green a house or apartment is.
Click here to read more.
ASK A BUILDER
By CCHRC Staff
The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.
Q: How can I keep condensation off my windows in the winter?
Condensation is a product of the relationship between humidity and temperature.
The warmer the indoor air is, the more water vapor it can hold. When the air moves next to a window it can no longer hold the same amount of water vapor because the temperature is colder close to the window. This is when you start seeing condensation forming. As an example, if your indoor temperature is 70 degrees and outdoor temperature is 0, then moisture will begin to condense on a single-pane window when there is roughly 15 percent relative humidity in the house. A double-pane will be subject to condensation at around 25 percent to 40 percent humidity, and a triple-pane will fall into a range of around 30 percent to 50 percent. These number ranges are based on average window insulation values.
A really good triple-pane window may be able to withstand significantly higher humidity levels before condensation occurs. The target humidity levels for occupant comfort in a home range from about 30 percent to 50 percent, however the lower end of this spectrum is considered safer in cold climates such as ours, due to concerns with condensation within walls and ceilings. When the humidity is really low, some people become prone to respiratory infections. Of course high humidity can cause similar problems with bacteria and mold growth in the building. As the winter air in Fairbanks is so cold and dry, it is usually difficult to attain anything close to 50 percent humidity in a properly ventilated house.
To keep condensation off windows, make sure your home is properly ventilated.
The presence of excess moisture around windows is a good indicator of the effectiveness of ventilation in your home. Shoot for the low end of the target humidity range, to keep both you and your home healthy.
Q: Can I face repercussions if my home is violating building code or it is out of date?
In Fairbanks, building inspectors primary focus is on new construction and remodels. When you are remodeling a home that is not built to code, inspectors only require that any new work meets current code.
Older parts of a building that are not involved in the remodel are not subject to same requirements, unless the inspector sees a situation that could jeopardize the life and safety of the occupants.
When it comes to code compliance, it is important to be aware that building codes are updated and revised on a regular basis. If your home is not up to date, do not panic.
Inspectors are not police that travel around town making sure residents bring their houses up to code. But remember, building codes exist to ensure the health and safety of the occupants, so a compliant house is a safe house. Furthermore, if you plan on selling your home, a buyer or lender may want an inspection before the sale is final. Any code violations will likely have to be corrected at that time. It would be better to deal with those issues before selling your home.
Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at akhomewise@cchrc.org. You can also call the CCHRC at (907) 457-3454.
ASK A BUILDER
By CCHRC Staff
The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.
Q: What are some of the risks with adding insulation to the outside of my home?
It is a complex issue, and what works in one part of the state may not necessarily work in another. The key to successful exterior insulation is to keep moisture from entering the wall from the inside and from the outside. If you cannot ensure this will not happen, then you are insulating at your own risk. If too much moisture moves into your walls or ceiling, then you could end up with mold and rot.
For years, people in Fairbanks and other parts of the state have been applying various amounts of foam insulation to the exterior of their houses. However, this method can also contribute to moisture problems if not done correctly. These problems can originate from inside or outside the house.
In local building code, cold climate construction requires a vapor retarder, placed near the interior wall surface. Most times this consists of a well-sealed layer of polyethylene under the sheetrock.
This barrier membrane is designed to prevent indoor moisture from getting inside walls where it can condense. When you have heat and humidity inside, and a leaky vapor barrier, moisture may get inside a wall. If there are not enough outside layers of foam insulation, this moisture will cool, condense and begin causing problems. Having the proper ratio of insulation on the outside of the wall to insulation on the inside of the wall will help solve this problem.
Also, if you have a good existing interior vapor retarder and add exterior foam, you are creating, what many call, a “double vapor barrier,” as the foam is also relatively impermeable. Should enough moisture find its way into a wall under these conditions, it may have a difficult time drying out.
In some environments, there is the possibility that rain water can work its way into the wall, especially in combination with wind. To minimize these problems, your home may benefit from large overhangs, gutters and proper drainage. Another option is a good draining type of house wrap installed in combination with adhesive or metal flashings, which are applied before putting on the foam. These steps will ensure that if any water gets behind the foam, it will drain down into the ground rather than soak into your framing.
If you put exterior insulation on your house, it will become much tighter. As a result, your indoor humidity levels may increase and the house may no longer receive enough fresh air, making it necessary to better ventilate your home.
An early indicator of elevated indoor humidity levels are your windows. If you are seeing a lot of condensation, especially on a good quality doublepane or triple-pane, that is a good reason to look for a cause.
Q: Are electric stoves more energy efficient than propane ranges?
Strictly, electric energy is very efficient in a range, but it depends on what the cost of propane is, and what the cost of power is in relation. You would have to figure out how much energy, in BTUs, you are getting out of your propane and what you are paying for your kilowatt hours, and compare the two.
Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at akhomewise@cchrc.org. You can also call the CCHRC at (907) 457-3454.
From The Daily Green:
Way beyond shipping container homes, these fresh green buildings are at the cutting edge of style and convenience.
Click here to read more.
ASK A BUILDER
By CCHRC Staff
The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.
Q: What windows are preferred for a passive solar home, double- or triple-pane? With or without coatings? Which coatings? What type of glass? Assuming standard building insulation, what is the sweet spot for percentage of glass area?
A: The idea for a passive solar home is a good one, but offers some significant challenges in our climate.
Based on a 1970’s study by University of Alaska researchers, in Fairbanks, for every month of the year besides December, a net energy gain with south-facing windows is possible, but only when the sun is out.
Given that our winters are very cold and have much longer periods of darkness, the heat losses through windows during the dark periods are much greater than the gains we make when the sun is shining. The solution here is a system of insulated exterior shutters. Then, even here in Fairbanks, you could have a house which benefits from a net solar gain for 11 months.
Unfortunately, a perfect heavily insulated shutter system has yet to be invented, but people have built their own shutter systems in typical Alaska style — anything from putting on a piece of 2-inch blue foam to a raise-able shutter that can be engaged with a hand crank from the inside. Keep in mind that, as with all sources of energy, you will make maximum use of solar gain by having an extremely well-insulated building shell. If you have an underinsulated, leaky house, you won’t get the same results.
In a cold climate, we want a window with a low U-value. The U-value represents the rate of heat transfer through the glass. The U-value is usually listed on a sticker on the window or is available from the dealer.
Currently, Alaska Housing Finance Corporation requires a “5-Star Plus” home in Fairbanks to have a window with a U-value of 0.25 or lower, which typically means a triple-pane window.
When it comes to glass and coatings, because we are primarily interested in optimum thermal performance, nearly all windows geared toward our climate will have some variation of low emissivity (low-E) coating designed to reflect radiant heat. Low-E glass usually has some type of metallic film bonded to one of the faces.
For a window with good insulating value, we want a coating that allows some of the short wave infrared energy from the sun to enter the house while minimizing how much of the long wave infrared radiation escapes from the heated space through the glass. This is a balancing act that is dependent on the types of coatings used, and which side of the panes of glass they have been placed on. Coating technology is improving steadily and it is worth the time to research the performance for any type of window line you are considering for purchase.
When it comes to finding the sweet spot of how much surface area should be glass, this varies too, depending on what you are trying to achieve.
In order to comply with the Alaska Housing Finance Corporation “5-star Plus” home requirements, the total window surface area should not exceed 15 percent of the above-grade wall area. The Fairbanks City Building Department uses the same standard. If you go over 15 percent, you will have to make up for those energy losses somewhere else. Often this means adding more insulation to another part of the building. The location of the glass also factors in: south facing works best while north facing should be minimized.
There is much more information on the subject than covered here, but an excellent resource is “A Solar Design Manual for Alaska” written by Rich Seifert from the UAF Cooperative Extension Service.
The book is readily available and accessible online.
Also, Seifert usually teaches a class on solar design in the spring, which is highly recommended to anyone interested in the concept.
Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at akhomewise@cchrc.org. You can also call the CCHRC at (907) 457-3454.
Learn how to do or direct your own energy efficient improvements. Attend an informative workshop FREE TO THE PUBLIC! Workshops are brought to you by Alaska Housing Finance Corporation.
The following workshops will be held from 6-8 pm at the Cold Climate Housing Research Center, 1000 Fairbanks Street, near West Valley High School and the University of Alaska Fairbanks. Call 907-457-3454 for directions.
February 1, 2010: Building Science Basics
February 2, 2010: Air Tightness
February 3, 2010: Ice Dams
February 4, 2010: Lighting & Appliances
February 8, 2010: Heating & Hot Water
February 9, 2010: Doors & Windows
February 10, 2010: Insulation
February 11, 2010: Ventilation
ASK A BUILDER
by CCHRC Staff
The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.
Q: I have a cold roof. The other day I noticed frost on the vents that are high up on the end walls of my house.
What should I do?
Frost on roof vents of a cold roof indicate you might have air leakage and moisture coming from somewhere inside the house, more than likely through the ceiling. So you have warm air getting into the attic, then out through the vents where it condenses and forms hoarfrost. There are a lot of places this leaking can occur. You could have a chimney or plumbing penetrations going through the ceiling that aren’t sealed properly, poorly sealed can lights, holes in your vapor barrier, or bathroom vents and fans that are broken or not properly connected to the outside.
When it warms up, crawl up into the attic and take a look. If there is so much frost that it is building up on the outside, then there could be some moisture damage inside.
Q: Are there any cautions for replacing windows in the winter?
Flanged windows, especially vinyl ones, get brittle in the extreme cold, so handling them takes a bit more care. Also, expanding spray foam, used to seal the gaps between the window and the framing, doesn’t cure well in low temperatures. The can instructions are pretty specific in this regard, and if you install a foam backer rod into the gap first, which stops the airflow from the outside, then you can spray the foam and it should work.
Q: What are some general rules on when to plug in your automobile?
The rule of thumb that the Alaska Department of Environmental Conservations provides is to plug in for at least a couple hours when it’s 20°F or colder.
I think most of us have realized that if it’s 20°F, you can get by plugging in at a lesser amount and if it’s quite a bit colder you need to plug in longer. If you find you need to leave your car plugged in substantially longer before it starts smoothly, then you car may need some maintenance.
Q: I hear the word “retrofit” being used a lot in talks about fixing up an old house.
What’s the difference between retrofitting and renovating?
Renovating simply means restoring something, making it look new again, or repairing it.
Retrofitting is modifying something old with new technology. In a home, upgrading an older energy system, using a new technique to insulate walls or replacing outof- date windows with new ones are examples of retrofitting.
Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at akhomewise@cchrc.org. You can also call the CCHRC at (907) 457-3454.
From The Daily Green:
You can get $1,500 or more in tax credits for these home fixes — if you do the work in 2010. So make these your new year’s resolutions.
Click here to read more.
ASK A BUILDER
By CCHRC Staff
The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy, and the many other parts of home life.
Q: What is a heat pump and can it work in Fairbanks?
A heat pump is a mechanical system that uses a series of liquidfilled pipes or tubes run underground to heat (or cool) a building. The liquid captures the ground heat and uses it to heat your home. You might think our Fairbanks ground would be too cold to support such a system, but even at lower temperatures a heat pump can still function appropriately. In Alaska, this tubing has antifreeze added.
In Fairbanks, these tubes need to be buried below the frostline (about 10 to 12 feet down) where the temperatures are fairly stable across the seasons. Heat pumps use more electricity than the typical house, but the increased costs are offset by the savings in fuel. There is some concern that, depending on your site, the heat pump will take enough heat from the ground to cause freezing, however more research needs to be done on this question. Locally, we’ll probably see more of these systems being installed in the next few years, but for now, it is an emerging technology for our area.
Q: My boiler needs to be cleaned. Is that something I can do myself, or should I call a professional?
You can do it yourself but it is a messy and sometimes difficult job. Older boilers may require removing side shields, top pieces, gaskets or other parts that can be damaged and cause leakage.
Most newer boilers have hinges and open from the front, making them much easier to clean. These boilers make it simple to get a brush onto the heat exchange surfaces and leave few places to gather soot. In the long run, it is probably best to have a professional do the cleaning.
Q: If I want to build a higher tech home and add some solar panels or wind power, how does orientation play into that?
Fairbanks is a tough place for wind power because it is generally a calm region of the state. The orientation of your home will not be a hindrance to adding any type of wind system as long as you have the wind resource. High areas in the hills around Fairbanks have the best potential for this kind of renewable energy system. Fairbanks is certainly a good place for solar much of the year. Solar systems should be oriented to the south in order to catch as much light as possible.
If you are building a new home, orienting it as much as possible toward the south will be advantageous for any kind of solar energy collection, whether passive or panels.
If you want to add solar panels on to your house, place them on your roof or outside walls at the height they will collect the most light.
Before making any decisions it is best to contact a solar installation company that can do an assessment of your property. These companies can do an analysis that will tell you where panels will receive the most sun exposure year round.
Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at mailto:akhomewise@cchrc.org. You can also call the CCHRC at (907) 457-3454.
ASK A BUILDER
By Cold Climate Housing Research Center Staff
The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.
Q: I have double-pane windows. Every year I get large amounts of frost buildup on the pane facing the interior of the house. I thought these were fairly nice windows since the house is only five years old. I’ve tried the shrink wrap window plastic, but that only works if I use it around the frame — in which case I can’t close my blinds. Can you explain to me what is wrong and the steps to fix it?
A: There are a couple of things that could be going on here. You might have high humidity levels in the house, especially if you don’t have an adequate ventilation system in your home. Target indoor humidity levels for human comfort and health are between 30 and 50 percent. You should be able to buy a digital hygrometer that will help you monitor your indoor conditions.
The windows are one of the first places you will see condensation forming because they are one of the coldest surfaces in the house. Here’s the bottom line: the higher the humidity and the colder the surface, the greater the condensation potential.
Several factors that will contribute to excess humidity in the home are: a crawlspace that doesn’t have a good ground vapor barrier; appliances that aren’t properly vented to the outside, particularly dryers and range hoods; aquariums; inadequate bathroom ventilation; firewood stored indoors; and high occupant loads to name a few. As an example, a family of four will produce roughly 10 pounds of water per day through respiration and transpiration.
The reality is that in a properly ventilated house in Fairbanks, levels of 30-50 percent humidity are difficult to achieve because the climate is so dry here.
In terms of condensation potential, this works to our advantage. With a tight under-ventilated house, however, it is quite possible to attain high humidity.
In periods of extreme cold, the indoor humidity levels should be lower to reduce condensation problems.
As you noticed, the shrink wrap plastic is effective as it essentially turns your window into a “triple pane,” improving performance. The other option is to insulate the exterior of the window. Rigid foam board is crude but effective, but that also has its obvious disadvantages. The easiest approach is to target the indoor humidity and identify potential problems in this area first.
Q: What types of boilers are out there, and what do I look at? How do I know which type of boiler is the right one to get and what size? A: Alaska is a cold and faraway place, but even in Fairbanks, we have a wide variety of boilers. Some common brands include Weil-Mclain, Burnham, Slantfin, Monitor FCX Condensing Boilers, Triangle Tube, Viessman, Buderus, Energy Kenetics, Low Mass Boilers, Quietside and even direct vent hydronic hot water heaters are pressed into service as radiant heaters for the home. Look for the AFUE efficiency and get recommendations from mechanical contractor and homeowners.
The best way to find out what size boiler you need for your home is to look at a heat/loss calculation for your specific house. You can have this calculation done by a plumber or through a home energy rating among other places.
The calculation takes into account the R-values of walls, windows and roofs, and the exposed surface areas of each, then estimates how much heat will leave the building at a specific temperature.
For Fairbanks, -40 F is often used. The right size boiler will offset the heat that is expected to leave the building. There’s an old rule of thumb that uses the square footage of your home to calculate the right boiler size.
Unfortunately, this will often call for too large a boiler. A boiler that is too large for your home will operate inefficiently.
Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at akhomewise@cchrc.org. You can also call the CCHRC at (907) 457-3454.