Category Archives: Uncategorized

Groundbreaking for the UAF Sustainable Village

The UAF Sustainable Village broke ground on Friday, April 6 on lower campus near the Cold Climate Housing Research Center.

The development will feature innovations in cold climate construction—with super-insulated building envelopes to minimize heat demand—as well as experimental approaches to energy, ventilation and wastewater treatment. The homes will serve not just as student residences but also as housing prototypes, building science labs, and teaching tools.

UAF students helped CCHRC develop the concept for the homes, through a design contest, and will help build and conduct research on the Village as well.

“The thing that’s unique about this project is it’s engaging students for the first time in the development of sustainable housing,” said Michele Hébert, who heads the UAF Office of Sustainability. “Our hope is that this will lead to more young people learning how to live sustainably and be future leaders in sustainability.”

The 1,500-square-foot homes will have an R-50-60 envelope and will use a mix of solar, biomass and conventional fuel. A 14 kw photovoltaic array was funded by the university sustainability grant.

The project will demonstrate that a highly energy efficient 4-bedroom home can be built in Fairbanks without breaking the bank. The budget is approximately $200,000 per home. The rent will approximate the cost of a mortgage for an equivalent new single-family home in Fairbanks and be competitive with dorm rates.

Construction will be done by seasoned carpenters along with UAF student workers. Student residents move in in mid-August, so we will be busy for the next few months!

Bethel school harnesses resources to save money

CCHRC is working with an education center in Bethel to help improve the energy performance of its new building.

Yuut Elitnaurviat is a vocational center that offers training in construction, health care, dental health aid, and other subjects for residents of the Yukon-Kuskokwim Delta region.

The new building at Yuut Elitnaurviat campus consumes more than 40 percent more than the average building in Alaska.

The school is spending more than 40 percent more than the average commercial building in Alaska for heating and power at its facilities—which includes a classroom, admin offices, a cafeteria, dormitory and shop—and the building is only a few years old. This stems from inefficiencies in heating, lighting, and ventilation systems, among others. For example, the air handling system is consuming more than its fair share of energy use and may be oversized for the building. In addition, the school is paying to heat much more domestic hot water than it actually needs.

CCHRC researchers visited the campus in March to explore options for improving the building’s performance.

“They’re paying almost 50 cents a kWh, and they’re using around 32,000 kWh a month, so it makes more economic sense to focus on the electric load than on space heating at this point,” said CCHRC research engineer Bruno Grunau.

CCHRC prepared a feasibility study of the local resources and found both wind and solar photovoltaic systems would be viable technologies. Researchers are now helping school officials plan a small wind farm and solar array. The wind farm could include up to 4-5 turbines, each producing approximately 6,000-10,000 kWh per year, and a 10 kW PV array that would produce approximately 8,500 kWh a year.

Building officials are also pursuing a commercial energy audit to find other economical ways to save energy, such as tightening the building envelope or installing high-efficiency lighting and daylight sensing.

 

How to build and maintain efficient, healthy walls

Are you curious about what’s in your walls, but not quite ready to tear them apart to find out? We’ve dissected a standard wall system to see what’s inside, and what it tells us about your home energy performance and the durability of your envelope.

Whether you’re building a new home or retrofitting an existing one, this video will show you the key to tight, long-lasting walls. It will give you an understanding of the three main issues facing walls in a cold climate: air leakage, moisture movement, and conductive heat loss. CCHRC building educator Ilya Benesch will show you how these effects are at play in yours walls, how to spot them, and how to deal with them. Enjoy!

Fuel monitoring: looking for answers inside the tank

CCHRC researcher Vanessa Spencer dips the tank to check the fuel level.

CCHRC researchers are taking advantage of the last few months of winter to test several methods to monitor fuel use at the household level.  The study, funded by the Alaska Housing Finance Corporation, is an attempt to identify a cost-effective and accurate method to monitor heating oil consumption across Alaska.  That data could then be used to evaluate whether state energy efficiency targets are being met.

Several different monitoring systems have been set up on both a boiler and a Toyo stove.  The systems vary in price and level of complexity. They include a floating gauge, ultrasonic fuel level sensors, electrical monitoring equipment, pressure transducers, flowmeters, scales and more.  Researchers will collect data from all the systems for one month before beginning to analyze and compare the systems. This summer, CCHRC will prepare a research report detailing how each system worked, how to set it up and collect data, how much the system cost, and the pros and cons of using it.

 

How do I keep my chimney clean and safe?

Most of our wood stoves have been put to good use this winter, and mid-winter is a good time for an inspection. One of the most common causes of chimney fires is pipe contact with combustibles. After years of exposing insulation and wood framing to heat, the ignition point of the material drops and it takes less to ignite it. So checking on creosote inside the chimney and clearance to combustibles outside the chimney is time well spent.

Since people in Fairbanks primarily use factory-built insulated metal chimneys, this article provides an inspection checklist for that particular type.

Examine the chimney wherever it is accessible, especially inside the roof.

  • On the outside of the pipe look for dents, missing screws or bands, rusted metal, heat discolorations, separation between sections, and any other abnormalities.
  • Perform the same inspection inside the pipe, with a powerful flashlight and a mirror if necessary. The pipe should be clean and smooth, with no defects or buildup.
  • Insulated metal chimneys should have an ID label and a rating. Call or visit your local building supply store to find who carries specifications for your brand of pipe. Product information is available online too.
  • Pay close attention to the required clearances between the pipe and any combustible surfaces, especially inside the roof. There should be no insulation touching the pipe, even if it is rated as noncombustible, unless specifically approved by the manufacturer. Insulation installed closer than the minimum air space allowed is a serious fire hazard.
  • Attic insulation shields keep the chimney pipe the proper distance from combustible materials inside the roof and are a standard off-the-shelf item. They can also be manufactured by local sheet metal shops for special applications.
  • On the roof, the chimney cap should be in place to control sparks and prevent water from entering the pipe.
  • The pipe should extend at least three feet above the point it exits the roof, and at least two feet above any wall, ridge, roof, or adjacent building within ten feet.  If it is more than ten feet from the peak, you should be able to measure down two feet from the top of the chimney and ten feet horizontally in any direction without contacting the roof. This is considered a minimum – a greater height may be necessary for draft and safety reasons.  Check with the manufacturer for specifics relating to your application.
  • Make sure the chimney is protected from sliding snow, particularly on a metal roof.  Snow stops, bracing, or crickets may need to be placed where impact damage can occur.
  • If you are installing a new chimney, be sure to inform your insurance company, as its policies may require notification and inspection.

Chimney sweeps and wood heat installation specialists can be good resources for questions and inspections.   If you are burning wood in an old untested chimney, a professional inspection and some new pipe can bring you peace of mind – instead of an emergency visit from the fire department.

 

What is the safe amount of exterior insulation to add in a retrofit?

Moisture control in cold climate housing is a critical concern, as moisture accumulation in the building envelope can lead to mold and rot. As homeowners in Interior Alaska add exterior foam insulation to their walls, they can lower their heating bills. However, if not done right, they can also create the potential for moisture damage.

To learn more about this risk, CCHRC conducted experiments over two years on wall retrofits in a mobile lab with nine test walls with different combinations of wood framing and interior and exterior insulation, some with a vapor barrier and some without. The research question: How much exterior insulation do you need to prevent moisture accumulation?

Throughout the experiment, we monitored the humidity and wood moisture content inside the walls. When we took the walls apart last summer, the wood sheathing ranged from clean to spotty to downright mold-covered. The walls with thick exterior insulation (65 percent or more of the total wall R-value) showed no signs of moisture damage. The walls with less exterior insulation showed a little or a lot of mold.

Insulation ratios

When you add exterior insulation, you change many things related to moisture control. The extra insulation will slow heat loss through the wall and keep the framing warmer in the winter, but it will also inhibit moisture from escaping in the summer. This balance of moisture buildup in the winter and release in the summer has allowed our homes to work in the Interior. So if you’re going to block a drying pathway by adding foam, the trick is to add sufficient insulation to keep your wall cavity warm enough so that water vapor does not condense on the sheathing. A wall system that achieves this should not have moisture problems, short of plumbing leaks or other major defects.

In our study, we found that retrofitting walls with foam is safest when 65 percent or more of the total wall R-value is outside the sheathing. Every other wall in the study (ranging from 59 percent to 30 percent exterior insulation) allowed moisture to accumulate during the winter and/or mold to grow. Because many residential retrofits have less than 30 percent of the wall R-value outside the sheathing, the durability of the wall becomes largely a function of indoor conditions. In these cases, the potential for moisture damage depends on the quality of a vapor barrier and interior humidity conditions.

Can adding less insulation than this 65 percent mark work in the Interior? Yes, but you’re taking more risk, and counting on humidity and pressure control measures to protect your house for you. This typically means having a mechanical ventilation system in your home, such as a heat recovery ventilator (HRV). Do you have an HRV? If so, do you maintain it? Your home will thank you if you do. If you don’t, today’s wall retrofit might be creating more work for you than you counted on.

To learn more about the Mobile Test Lab, read the four-page report here.

Snow Loads

After a snowy December, Fairbanks has received a respectable (though still below-average) 30 inches of snow so far this winter.

Which makes some residents start pondering snow loads.

Roofs are required to withstand 50 pounds per square foot in the city of Fairbanks.

Snow loads vary across Alaska, depending on where you live. For example, winter snow loads can range from up to 300 pounds per square foot (psf) in Whittier down to 25 pounds in northern Alaska. Many factors affect snow load, including the moisture content of the snow, seasonal accumulation and drifting.

The weight of snow depends on its moisture content, which will vary depending on the conditions. The moisture content of snow ranges from about 1 percent to about 33 percent (water weighs about 62 per cubic foot). Compressed snow, and even snow that simply accumulates over time, will be heavier than fresh snow.

Fallen snow can also pick up humidity from the air and increase in weight.

You determine weight by using a measurement called snow water equivalent (converting inches of snow into inches of water by taking a cylindrical core sample of snow and melting it). You can find the daily SWE for different locations in the state, including Fairbanks, at the USDA Natural Resources Conservation Services website at www.wcc.nrcs.usda.gov/snotel/Alaska/alaska.html. On Wednesday, for example, the snow depth was 16 inches and the SWE was 2.4 inches. To calculate pounds per square foot, you multiply the SWE by a conversion factor of 5.2 (check out the formula here: www.ak.nrcs.usda.gov/snow/data).

That gives you a snow load of roughly 12.5 psf. Keep in mind that this number is designed only to provide an estimate for the region.

Building code in the city of Fairbanks calls for roofs to withstand a minimum of 50 psf, but homes built before 1991 were required to carry 40 psf and older homes even less. Mobile homes can be built to carry just 20 psf.

But keep in mind there is no building code outside of the city limits. Roof snow loads can vary depending upon type of roof, roof slope, melting and re-freezing of snow and ice, among other factors. Sloped roofs that periodically shed snow load present benefits and risks. If snow slides safely onto open ground, there’s no problem.

But if that snow hits a deck on the way down, its force is multiplied many times more than its resting weight and can shear otherwise stable structures right off if they are not supported sufficiently. Or if snow slides onto a flat roof or other surface, its cumulative weight is magnified from than that of normal snowfall. Structures should be designed with overhangs or other features to offer sliding snow a safe path to the ground. The ability of chimneys or utility poles to withstand sliding snow should also be considered.

In addition, decks, sheds, greenhouses, campers and other structures built without permits or an inspection may not be able to handle much if any load depending on the quality of the workmanship.

An underbuilt roof structure may also be at risk for collapse from imbalanced loading.

How do you know if you have a problem? Well, if you’re not privy to the design specifications of your home, the safest route is to hire a structural engineer to inspect your home and do the math. An inspection can also reveal potential weak spots or places where your roof structure, deck, or framing might fail. Consider how additions or modifications might affect your home’s ability to support snow. Wood tends to be very flexible and can withstand a lot of force over time before it snaps. But eventually, if it is not built to the task, it can fail.

Clearing excess snow off your roof or deck is not usually necessary unless you are dealing with an older home, structures that are built to dubious specifications, or an extraordinary buildup of heavy snow. Clearing snow comes with its own risks — like falling off your roof.

Also, the addition of your own weight on an already stressed roof can make matters worse. If you suspect a roof might collapse (you witness sagging or hear creaking), get down immediately.

How can I maximize the efficiency of my refrigerator?

Refrigerators are often overlooked in the dialogue of energy efficiency. Typically, a new refrigerator with automatic defrost and a top-mounted freezer uses about half the energy of a 1990 version. So if your refrigerator is old and needs repairs, or is close to the end of its expected life, which could be around 15 years, then it makes good sense to replace it.

A new refrigerator with automatic defrost and a top-mounted freezer uses about half the energy of a 1990 version.

You can also enhance the efficiency of your fridge through proper maintenance. Seals can become brittle or lose their compressive memory, which can cause small gaps. As a rule of thumb, you shouldn’t be able to take a piece of paper and slide it between the seal. Another way to test the seal is to stick a flashlight inside the fridge. If you turn off the lights in the room and can still see light coming out of the fridge, then it’s probably time to replace the seals.

 

The refrigerator compartment should be between 36F and 38F and the freezer should be between 0F and 5F. You can’t always trust the dial in the fridge, so if you really want to be sure, put a thermometer inside and use the dial setting as a point of reference to make sure everything is working as it should. You may also want to clean the condenser coils, which are located at the back or bottom of the fridge. They can collect dust and force the fridge to work harder to do its job.

The location of your fridge is also important. If it’s sitting in the sun, next to the stove, or in any other warm spot, it will use more energy trying to stay cold. A fridge in a cold space will work the opposite way and save energy.

When you’re preparing food to go into the fridge, let it cool down fully before storing it away. Remember, a refrigerator is a temperature-regulating appliance. Hot food will raise the temperature inside the compartment and the fridge has to work harder to bring that temperature down to the level it is set for.

If you’re considering buying a new fridge, top and bottom units tend to be more efficient than side-by-side units. However, the bottom line when buying a fridge, or any appliance, is the yellow Energy Star tag. Energy Star information will tell you kilowatt hours per year for your model, which you can compare with other models.

Your Northern Home: crawl spaces

CCHRC recently released the pilot for “Your Northern Home,” a series of educational videos geared toward Alaska homeowners. The 12-minute video focuses on crawl spaces–the very important but often overlooked space underneath your home where moisture problems often originate. Host Ilya Benesch describes how to maintain a dry, healthy crawl space through insulating, air sealing, heating, and waterproofing.

Is my heating system the correct size for my house?

A hot fire burns more efficiently than a smoldering fire.

Just like skiers ride best with the right sized boots, your house needs a properly sized heating system to perform at its highest efficiency. Oversized heating systems are inefficient and cost more, both upfront and in ongoing maintenance, than a heating system that fits your home.

Heating appliances are sized by the amount of heat they can provide in one hour. This heating capacity is measured in BTUs per hour (one BTU is about the amount of heat energy produced by burning one match).

The heating capacity of your system should match the peak hourly demand of your house. Peak hourly demand is the maximum heat required by a house in one hour on the coldest day of the year. For a rough estimate, a well-insulated, two-story house in Fairbanks might require 60,000 BTUs per hour on the coldest day of the year, so a heating appliance should be rated to produce that much heat.

A properly sized heating system will run continuously on the coldest day in order to keep the home at its set temperature. This means the system is running at its steady-state efficiency, the stride it hits after warming up. Steady-state efficiency is like the miles-per-gallon your car gets cruising on the highway as opposed to riding in stop-and-go traffic.

Oversized systems, on the other hand, tend to cycle on, produce lots of heat, and turn off. The cycling on and off wastes fuel (as the appliance repeatedly ramps up and cools down) and causes wear and tear on the mechanical system (which ultimately requires more maintenance).

Wood- and coal-fired devices can also be oversized. When a wood stove is too large, residents tend to burn fires at a low smolder to prevent overheating the house, which is not only less efficient but also emits more particulates than a hot fire.

Domestic hot water systems should also be properly sized. For example, storage water systems are sized by their First Hour Rating (FHR), the amount of hot water in gallons the heater can supply per hour, starting with a full tank of hot water. The FHR (determined by the size of the water tank, source of heat, and size of the burner or element) should be within a few gallons of a building’s peak hourly hot water demand. F

or example, a household of three who routinely shower at night while running a dishwasher may have a peak hourly demand of about 45 gallons. So the house would need a domestic hot water heater with a First Hour Rating of 40-50 gallons. For tankless water system, the size depends on water usage, fuel input and the temperature of the incoming water.

The size of a heating system is directly related to the efficiency of your home. So if you make any building envelope upgrades to your home, you’ll require a smaller heating system—a good reason to make upgrades before replacing your heating appliance.

Sizing your system

Rule-of-thumb methods should not be used to size a heating system because today, sophisticated computer software exists that can help contractors with this task. Contractors in Alaska should use one of two methods to determine the proper size of your heating system:

–ACCA Manual J by The Air Conditioning Contractors of America

–AKWarm software, maintained by the Alaska Housing Finance Corporation, provides sizing methods for heating systems.

Don’t be afraid to ask your contractor how he will size your heating system, and ask to see the calculation.  Remember: a properly sized heating system will save you money.

You can calculate your hot water peak hourly demand for a storage water heater at the U.S. Department of Energy website on hot water heaters: http://www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12990