Category Archives: PORTAL

Prevent heat loss with exterior insulation

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.

These days, it is popular to put foam insulation on the outside of buildings.  How did all this come about? 

      A building loses heat through its framing, which is called “thermal bridging.”  Wood has less insulative value than any kind of insulation.  For instance, a wood stud has an R-value of 1.25 per inch.  If a building has a standard framed wall, whether it is 2×4 construction, or 2×6 construction, the studs span from the interior of the wall to the exterior of the wall. For a 2×6 wall, that would give you an R-value of about R-7 where the stud is located.  If you were to take all the studs in a wall and stack them side by side, you would have a wall that is 11-25% wood depending on how it is built.  Even if a wall is full of R-21 fiberglass insulation, the insulative value of the wall is dramatically worse when you average in the less insulative value in the wood.

      At least 20 years ago builders began experimenting with putting insulation on the outside of homes as a way to stop heat loss created by thermal bridging. Adding foam to the outside of a wall “wraps” your home in a continuous layer of insulation, thus preventing other building materials from conducting heat to the outside and cutting down on the air leaking out of your house.  This technique has been used in many cold climate regions.  The PERSIST (Pressure Equalized Rain Screen Insulated Structure Technique) is an exterior insulation technique that has been used in Canada for many years, while the REMOTE (Residential Exterior Membrane Outside Insulation Technique) Wall System is popular here in the Interior. 

Where can I recycle glass in the interior? 

      Recycling glass is a challenge because the material is heavy and difficult to ship out of Fairbanks and then out of Alaska.  Also, Anchorage recently ended their glass recycling program, in part because the market for glass is currently not very good. 

      Here in Fairbanks, there are a few small artisan-type businesses that are reusing glass, but they cannot handle large volumes and typically have more than they need already.  However, the Borough Recycling Commission is looking at ways to use glass here locally potentially as road fill and construction fill.  These plans will take time to develop, so if you have any input, contact the Recycling Commission through the Fairbanks North Star Borough at 459-1000. 

Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC).   If you have a question, e-mail us at  You can also call the CCHRC at (907) 457-3454.

Ventilation is key when fighting condensation around your home


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 You can also call the CCHRC at (907) 457-3454.

Get in the know about plugging in your car

By CCHRC Staff home life.


Q: Is there anything I need to be cautious about when plugging in
my automobile?Q: I’ve seen that there are now roof shingles that are solar panels.While a wide range of solar technologies work in Alaska and other cold climates, photovoltaic roof shingles are still too new and untested for cold regions. The basic concept of solar shingles is excellent because the space is usually wasted and basic support structure is already in place. But remember, things perform differently in our extreme climate. If the shingles are glued on, you have to check how that glue performs in cold temperatures. When it comes to solar technology, there are some general rules to be aware of. Anything that applies to solar means you have to have a good exposure to the sun, preferable facing south.Q: What is a heat recovery ventilator and what does it do?

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

For starters, there are the basics of electrical safety: when you are plugging in anything, you do not want to make direct contact with the circuit because of the risk of electric shock. Besides that, a lot of Fairbanks car fires can be attributed to improperly maintained vehicles. Oil leaks, fuel leaks or other heating elements can be ignited by a small spark. Because winterizing cars in Fairbanks includes installing electrical heating devices, people need to be more cautious about leaks because of the risk of fire.

So if you have leaks, get them checked out and perform any other standard car maintenance.


Could those work in Alaska?


The shingles are going to be covered with snow, so how will that factor into their

East or west might work too, depending on how your roof is built and the pitch of the roof. Consider all the options before choosing a system.


A Heat Recovery Ventilator, or HRV, is designed to bring fresh air into your home. The “tighter” your home is (fewer leaks in insulation, doors and windows), the more essential an HRV is to the safety of the occupants. The other important part of an HRV, heat recovery, means it captures as much of the heat that is leaving the building as possible. You have already heated the air in the house.

To bring fresh air in, you are going to have to expel stale air, but that air has heat in it that you do not want to waste. So the HRV acts as a heat exchanger. As cold fresh air moves in, the warm stale air moves out. When the two air flows pass by each other, the heat from the warm, stale air is transferred to the cold, fresh air through a heat exchanger. These devices will help keep your home warmer in the winter, while saving you energy and money because you do not have to reheat the air coming into your home quite as much.

Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at You can also call the CCHRC at (907) 457-3454.

How to cope with outside insulation


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 You can also call the CCHRC at (907) 457-3454.

Tuck offers homeowners help with energy upgrades

From Alaska Dispatch, Sunday, January 17, 2010:

An Anchorage lawmaker says he’ll file a bill offering middle class homeowners — strapped for cash and still reeling from high energy costs — a back door into energy efficiency upgrades.

We reported recently on the lack of follow through by thousands of Alaskans who started a home energy efficiency rebate program, funded by the Legislature and managed by Alaska Housing Finance Corp. Those who start with a baseline efficiency audit have 18 months to fund repairs, schedule an audit of efficiency gains, and apply for up to $10,000 in state reimbursements. That window is running out for many folks.

Rep. Chris Tuck, an Anchorage Democrat, talked with people in his district and discovered some who have been hit pretty hard by the 2009 economic collapse. The families make too much too qualify for a low-income state weatherization program, but are dealing with high credit card debt, receding retirement accounts and investments, and, at times, negative equity in their homes.

Those circumstances can make it pretty tough to pay several thousand dollars up front for efficiency upgrades, even with a state reimbursement likely down the road, Tuck acknowledged.

Click here to read the full story.

Windows offer more than a view, but you have to know what you’re installing


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 You can also call the CCHRC at (907) 457-3454.

Homeowners are passing on energy rebates

From Alaska Dispatch, Wednesday, December 23, 2009:

Massive initial interest in a state program to help people make their homes more energy efficient could be tapering off, even as some areas of the state face the likelihood of increased home heating costs in coming years.

As of Dec. 16, nearly 19,000 Alaskans have started the multi-step Home Energy Rebate Program funded by Gov. Sarah Palin and the Legislature and managed by the Alaska Housing Finance Corp.

They’ve paid for certified technicians to rate their current home energy efficiency and recommend upgrades that would be eligible for a state refund, up to $10,000. But only about 200 people have followed through with improvements and filed their claims, and the window to do so is closing daily for the flood of folks who jumped at the chance.

If this trend continues during the next several months, the program will end up with a financial cushion of funds set aside for improvements that weren’t cashed in on. But it’s leaving some to wonder: In a state with some of the highest energy costs in the nation, where homeowners stood to benefit significantly — exactly what happened?

Click here to read the full story.

PORTAL and ACHP to host consumer workshops

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

Frosty rooftop vents might mean trouble in the attic


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 You can also call the CCHRC at (907) 457-3454.