Ask the Expert - Energy Efficiency for Today's Log Home

We know you have questions about the energy efficiency of log homes. We've asked industry experts, Katahdin Cedar Log Homes to help us with the answers.

Written by Amanda Phillips


Log homes are reliably energy efficient, but that achievement goes beyond the logs. Improvements in other building materials and developments in log home construction methods to bolster the energy efficiency of logs while retaining the home’s log look have improved home comfort and lowered heating costs.

Each month in our Log Home Living Newsletter we will feature one question and answer. If you're not already receiving our weekly newsletter, you can sign up here.

We'll archive all the questions on this page for easy reference and if you've got a question, please email Amanda at

What are the pros and cons to choosing metal roofing?

For some people, a metal roof is a must to complete that classic log home style. As you're researching roof options, you'll no doubt read about the benefits of metal roofing, as well as the drawbacks.

Let's start with the pros:
Metal roofing is long-lasting and resists fire and mildew. New styles of metal roof shingles mimic the look of classic wood shingles. Standing seam metal roofs provide traditional rustic style. Metal roofing comes in a range of colors.

Special coatings can be applied to metal roofing to make it deflect the radiant heat of sunlight, keeping a home's interior cooler and more comfortable during summer months. Solar arrays can also be installed on a metal roof, so metal roofing can represent a "green" choice for your home.

Now for the cons:
Metal roofing costs more than ordinary asphalt shingles. Lower-grade metal can have a finish that degrades over time, so be sure to ask about a warranty on the finish. Metal roofs can be damaged from flying debris during extreme storms.

As with all the materials you specify when building your dream home, roofing presents an opportunity for you to create a distinctive style. It's also another area where you'll need to weigh upfront costs versus costs spread out over the lifetime of your home.

Published on: April 9th, 2018. 

Do you suggest conducting a blower door test and/or infrared screening to find problem areas throughout the home?

To find out just how energy efficient homes are, the Residential Energy Services Network developed the Home Energy Rating System (HERS). One way to measure a HERS score on a log home is with a blower door test. During this test, a powerful fan is positioned at a sealed exterior door and pulls air out of the home, lowering the air pressure inside. An infrared camera can then be used to find areas where higher outdoor air pressure is leaking into the home.

With a log home, this test can show if caulking between logs is holding up and how well the logs have been seasoned. Leakage can often happen where walls and ceilings intersect, so caulking in these areas is critical to a weathertight home.

An energy performance assessment also looks at leakage in ducts, the effectiveness of insulation and heat loss through air leaks. The results are used to assign a HERS score.

Infrared screening, or thermographic inspection, can also be done to show variations in surface temperatures inside or outside a home. These readings can also detect areas where air is leaking or insulation is needed.

At Katahdin Cedar Log Homes, we've noted that our Northern white cedar logs outperform other wood species in blower door tests year after year. We attribute this to the species' low moisture content. Dry wood shrinks less, resulting in a tighter home with lower HERS scores. In fact, homes we built several years ago in the extreme climate of northern Maine maintain low HERS scores -- saving their owners money in annual heating costs. Our energy-envelope building system and high-quality windows also add to the homes' efficiency.

If you'd like to have your home tested, search for a blower door service provider in your area.

Published on: March 21st, 2018

What is HERS score and should it matter to me?

When we're buying a car, one of the things we look at is its fuel economy. How many miles can you get to the gallon? But energy performance doesn't just apply to the automotive industry -- your home should achieve top energy efficiency, too. If only there was a way to measure "miles per gallon" for your home. Well . . . there's a way. And it's call a HERS rating.

HERS (i.e., the "Home Energy Rating System") was developed by the Residential Energy Services Network (RESNET), a non-profit organization to help homeowners reduce the cost of their utility bills by making their homes more energy efficient. It's a comparative tool that rates a particular house as compared to an average home in the U.S. on a 100point-average scale. Since her HERS Index measures the amounts of energy consumed (an undesirable thing), a score lower than 100 means that it performs better than average when it comes to fuel efficiency.

Using a variety of technical equipment, a HERS-certified inspector will examine your home's insulation, windows and doors, the HVAC system and other home elements like alternative energy sources and ductwork. It includes a blower-door test, which identifies any air leaks in the exterior envelope that would affect the home's efficiency. The results are compiled and entered into a computerized simulation using the RESNET software to compute the final HERS score.

The results absolutely matter, because they don't just decrease your carbon footprint -- they can put money in your pocket in two ways: 1. By identifying and repairing any problem areas, you stand to save considerable amounts of money on your energy bills; and 2. A good HERS rating can increase the value of your home and give your home an advantage when/if you decide to sell. And that's a win-win for everyone.

Published on: March 12th, 2018

What methods for energy savings can be employed by the log home supplier?

Following the building code requirements will address about 90 percent of your log home's energy efficiency requirements. In fact, there are two codes your builder should be intimately familiar with: The International Residential Code (which is the basic code for all residential construction) and the ICC-400 Standard for Log Home Construction. The latter is the bible for proper log home assembly and sealing, and, if followed, will make your house energy efficient. This includes how to attach log walls to foundations and roof systems, sealants between log courses and at the corners, as well as window and door openings. Your builder should be checking at every stage of construction to make sure that it is exceeding the code requirements.

How do you know it meets efficiency expectations once it's built? A key indicator is whether it can pass a blower-door test. This test pulls air out of a house with a powerful fan attached to an exterior-door frame, then identifies places where air seeps back inside (often the gables, where the subfloor meets the log courses and of course, doors and windows).

Do the HERS test twice: right after the insulation is put in but before any trim work, baseboards or coverings (e.g., tongue-and-groove, drywall, etc.) are applied, and after the home is completely finished. Costing roughly $150-300 per inspection, it's a simple, low-cost way to determine your home's air tightness. If you should find weak spots, it's your builder's responsibility to seal them up; however, to safegaurd yourself, mandate that the home pass a blower-door test in your contract with your builder.

Published on: March 1st, 2018

Should I ask for specifics on sealing the air penetration places throughout a house, such as windows, doors, attics, crawl spaces, where the roof meets the floor and unfinished basements? What do I need to know?

A universal truth of construction is that anytime you remove a portion of a wall, whether it's a window or a door, you create the opportunity for air infiltration. The same applies where the log walls stop and other structural components, like foundations and roofs, start. All of these joints and openings must be properly connected and completely sealed to create a tight envelope.
While you're evaluating builders for your log home, it's a good idea to ask them how they address these important points of construction. But how do you know if the answers they provide are good ones? Let's use window sealing, as a specific example.
In a full-log home, settlement has to be taken into account. When windows are set, the installer typically does a good job of inserting the window into the buck (the casing that the widnow attaches to, which then is attached to the log walls, allowing the window to stay in a static location as the logs move). It's the area between the buck and the logs where the air could leak through, because that's where the builder intentionally leaves room for settling. But there are techniques to properly insulate and seal this space so you can have an air-tight log home and still accomodate for movement.
For example, after the logs are cut and before the bucks are inserted, your builder should ensure that the window openings have straight, linear cuts. If they aren't even, you open yourself up to issues. If one log is even as little as 1/4-inch shorter than the one above or below it, there will be a gap. As the logs settle, the gap could allow air to penetrate.
Next, it's critical that before the windows/bucks are installed per your manufacturer's system, the builder inserts a compressible foam sealant called a "sill seal" into the cavity. Once the buck is nailed into the logs, the sill seal fills the gaps; but because it's not adhesive, it allows the logs to slide and settle properly.
Then, when the windows are completely in place, the entire buck should be sealed with a bead of caulk, which will then be swathed in window tape, which will be concealed by decorative trim, inside and out. At this point, the window is sealed and, if done properly, will be about 98 percent effective at eliminating unwanted air infiltration or escape. (Of course, the quality of the window you choose will also play a key role in its energy effectiveness.)
Likewise, it's essential to have tight connections where the first course of logs attaches to the foundation material and the last course affixes to the roof. Not to mention that to recap the most benefits from energy-efficient construction, you shouldn't forget about insulation. There are a variety of ways to insulate your log home's non-log cavities, like an attic. Everyone is familiar with fiberglass batt insulation, but that's not your only (or most effective) option. Blow-in cellulose has nearly triple the efficiency of batt insulation and structural insulated panels (a solid-foam core sanwiched between two layers of oriented strand board), which are probably the most energy efficient option of all, are becoming a more popular choice. When it comes to basements, insulated concrete forms )ICFs) will provide better insulation than standard poured concrete or masonry blocks.
The best you can do is ask your builder as many questions as needed to feel comfortable that he/she is knowledgeable. The more questions you ask, the more you builder will recoginze that energy efficiency is important to you.
Published on: February 8th, 2018

How does moisture content and settling affect my home’s energy efficiency?How does moisture content and settling affect my home’s energy efficiency?

There are many things that can affect the quality and energy efficiency of your log home. One that is often overlooked is how dry or how much water there is in your logs. This is referred to as moisture content. The drying process takes place when wood exchanges moisture with air. The rate and amount of dryness depends on the relative humidity and temperature of the air. This moisture relationship has an important influence on the quality and performance of your log home.

High moisture content in your logs can have a detrimental effect on the heating and cooling of your log home. If your logs have a moisture content above 12%, noticeable shrinking will occur as your logs dry out. Because the logs will shrink at different rates, gaps between the logs will slowly appear. Installing caulking and foam between the logs and chinking the exterior may help alleviate air leakage. However, all of these products have limits to their stretching and swelling abilities. The best way to prevent air infiltration in your log home, and increase its energy efficiency, is to buy logs that are dry before they are erected.

The optimum moisture content differs depending on your climate. An average of 12% or less in most areas of the U.S. dramatically minimizes potential air leaks because most, if not all, of the shrinkage has already occurred. With very minimal air leakage your log home is much easier to heat and cool because the conditioned air stays in your home.

When speaking with the log home companies of your choice, please remember to inquire about the moisture content of the logs your home will be built with, because dryer will always be better.

Published on: January 11th, 2018

Should we hire an Energy Rater?

As regular readers of this column would recognize by now, there are a LOT of options when it comes to increasing energy efficiency of a log home. But how do you know which options will work best for you? Hiring an Energy Rater can help. Here’s how:

RESNet, a non-profit organization based in California that develops industry standards and training to conduct home energy ratings, has developed the Home Energy Rating System, or “HERS.” The HERS rating ranges from 100, which would match your home against an average home’s energy usage in your area. Scores descend from there, with 0 equaling a “net zero” home, meaning that it produces and consumes an equal amount of energy. Negative number scores indicate that the home is producing more energy than it needs.

There are a number of benefits to achieving a low HERS score. The first and biggest benefit is that your home will be more energy efficient, more comfortable and cost less money to operate year-round. A home with a low HERS score can also help you save in other ways. Studies have shown that energy efficient homes enjoy a higher resale value. Your bank loan officer may also note another study that showed energy efficient homes have an average 32% less chance of mortgage default. So, documenting your home’s energy efficiency can make your home more valuable and a more attractive risk to lenders.

For new construction, it’s a good idea to contact a RESNet rater while you’re still in the design phase. The energy rater can work closely with the design department and your builder to evaluate the plans, solar orientation, HVAC specifications, windows, doors and insulation to develop an initial HERS score. The rater can then evaluate and advise possible changes that might yield higher energy savings. All the information is entered into the RESNet software and stored for future reference in tabulating the final score.

After your plans are finalized, the Home Energy Rater will inspect the home at least two times: first, when the exterior envelope is completed but prior to interior finishing with cedar tongue-and-groove paneling or wallboard. And again once construction is completed.

The average cost for a start-to-finish new construction consultation is between $400-800. The final figure is often based on geographic location, as well as the size and complexity of the home. RESNet’s website has a locator tool [] where you can search for RESNet Energy Raters in your area. Any professional located on the website is certified and up-to-date with training.

We encourage everyone to include energy auditing in their home construction budget. It really is money well spent!

Published on: July 27th, 2017

Does “smart home” technology really increase your home’s efficiency, or is it just a gimmick?

Most homeowners these days are extremely concerned with their home’s energy bill and log homeowners are no exception. After all, you may pay off your home in 10, 20 or 30 years but, unless your log home is totally off the grid, utility bills are forever.

If you’re concerned about energy efficiency, the first, most important step is to build a well-insulated and sealed log home and make sure it’s properly orientated on your land to take advantage of passive solar gain. But beyond that, what can a homeowner do to increase and maintain energy efficiency once their home is built? Smart home technology actually does have the answers.

When we say “smart home technology,” we’re not talking about George Jetson’s sky pad. Rather, we are talking about new home innovations that can monitor your energy usage to help you regulate your home’s heating, cooling and energy usage.

The Sense Monitor is an excellent example of this. The monitor is a small device that plugs into your electrical panel and reads the unique electronic signature of all the things in your home that are plugged in. By reading these signatures millions of times per second, the Sense Monitor can actually differentiate between them to tell which is which. Using Wi-Fi, it then sends all of this data to an app for you to review. This makes it easy to see where your energy is going and what you may need to adjust to save money.

Smart home technology also can assist with your home’s heating and cooling. Smart thermostats, like the ones offered by Nest and ecobee, can take human error out of managing the temperature and humidity of your home. You set the temperatures you’d like to see and the thermostat will make small adjustments as needed to keep all your rooms in line. Smart fans and smart lighting technology are great ways to conserve energy as well.

As you plan your log home it would be beneficial for you to take some time and research which smart home technologies you can incorporate. A little financial investment now could add up to big savings in the long run.

Published on: June 29th, 2017

Does the way my home is positioned on my land affect its energy efficiency?

The short answer is “absolutely!” Everyone is looking for ways to save money, and properly siting your home to take advantage of passive solar gain is one of the easiest and smartest ways to accomplish that goal. Here are four options.

1. Take one long side of your home and point it true south so your home can soak in the sun all day, increasing your passive solar heat gain and natural light. If you ever think you’re going to put solar connectors on your roof point them true south as well to get the maximum benefit, but make sure to tell your manufacturer or builder if so they can make sure your home is solar ready.

2. Design an adequate roof overhang. A 2-foot overhang blocks the summer sun, keeping the home cool, while letting in the winter sun to warm it up.

3. Position the kitchen and living room (the places you’re most likely to be in during the daylight hours) true south so that they are getting all the daytime sun (this also saves money on your lighting bills). Place bedrooms on the east side of the house so you get the morning sun in the bedroom to wake up to.

4. On the east and west sides of your home, we recommend using deciduous trees, dwarf or mini dwarf (like fruit trees) in your landscaping to create shade during sunrise and sunset. In the summer, when their leaves are in they will block the sun, keeping your home cooler. Then in the winter, the leaves are gone which will let more sunlight in, keeping your home warmer. Fruit trees are easy to prune to the appropriate height (and you get the added benefit of home-grown produce!)

Published on: May 11, 2017

What are some easy elements I can plan in my home to increase efficiency?

Good question – and one we get asked a lot. There are two basic ways to give a log home’s energy performance a boost: through design and through materials.

If you’re planning a new log home, make sure to take advantage of the efficiencies you can gain through smart design choices. For instance, align/stacking your bathrooms. If you line them up perfectly on top of each other you cut down on the amount of piping from the hot water heater. It is wasted energy if the hot water has to travel long distances to get to you. If that’s not possible, or you’ll need a bath at the other end of the house, talk to your plumber about setting up a smaller on-demand water heater so they aren’t using energy when they’re not needed.

Another design option is to add a three-season room (so named because they’re used by people in the Spring, Summer and Fall) and place it on the north side of the home. Why? It will be the coolest room in your house during the summer months. Then in winter, you will use less fuel because it acts as a buffer against the elements for a large section of your home exterior.

When it comes to materials, you can’t go wrong with investing in high-quality windows and doors.

Glass is a very poor insulator but good conductor. So, when designing your home and putting windows in it you need to be cognizant of where you place the glass. Choosing the right placement based on your area will help you maximize the natural heating and cooling available in your house.

How do you know if you’re getting energy efficient windows and doors? The shortest answer is to look for the EnergyStar seal. It used to be easy for a company to get but they’ve tightened up the requirements in the past few years, and now you truly have to be efficient to get it. In the U.S., the top three best-ranked windows and doors will have the EnergyStar rating. You can also look at their U-value, but remember U-values are like golf: the lower the number, the better the score.

Published on: April 20th, 2017

Should I consider a geothermal system for my home?

Geothermal (harnessing the natural warmth of subterranean soil) is one of the most intriguing renewable energy options available, but few people understand how it works or how fruitful the benefits can actually be. To help you decide if it’s right for you, let’s look at the basics.

Geothermal systems transfer energy from the ground to energize a ground-source heat pump inside the home. How? By using a ground source heat pump as the converting appliance, the energy from the ground is collected by circulating water or an antifreeze solution through loops of tubing, which are laid out in trenches at a certain depth, then covered with soil.

Once in the ground, the fluid in the loops is naturally heated to a consistent temperature, usually around 50 degrees. No matter how cold or hot the air is, below ground that temperature remains the same. The warmed fluids are pumped into the home where the energy is extracted by the heat pump, then circulated back into the ground loop to be heated again.

By way of comparison, traditional HVAC systems burn fuel to create heat or use a large amount of electricity to energize a heating element to create heat, whereas heat pump-based systems transfer energy from one place to another.

Geothermal systems use small amount of electricity to pump the fluids through the underground loops and then extract the transferred energy to heat or cool the home, adding up to significant savings on electric bills.

So if you live or are building in an area where electric utilities are high, you want to reduce your dependence on fossil fuels or you’re hoping to achieve a green certification like Passive House or LEED with your log home, geothermal systems can help you reach your goals. The upfront costs are higher than other systems but the long-term benefits, and savings, are great.

Published on: February 2nd, 2017

What can I as the home owner do as far as design aspects to ensure energy savings farther down the road?

Watch this presentation from Katahdin Cedar Log Home's President and CEO, David Gordon. Click here to view Energy Saving Solutions for Your Log Home.

Published on: January 5th, 2017

Is air sealing your home as important as insulating your home?

Sealing your home against air infiltration is as important as insulating your home. If your home is not properly sealed, you will spend more money on cooling and heating your home than is necessary. Incomplete or improper sealing will also contribute to uncomfortable drafts and give insects and dust an opportunity to enter your home.

The impact of little or no sealing can dramatically increase the cost of heating and cooling in a windy location because the insulation in your home will have little to no effect because the wind can remove the conditioned air before the insulation has an opportunity to stop it.

The best way to minimize air infiltration in a log home is to make sure that you buy very dry logs. A moisture content of 15% or less is the most desirable because dry logs have minimal movement so there is less chance for a seal failure. (U.S. Department of Energy)

Also, pay close attention to all of the transition areas in the home. These are areas, such as corners, and intersections where walls meet the roof, walls meet foundations and where windows and doors meet walls must be properly sealed. Also, fireplaces and chimneys need special attention.

It is generally inexpensive and easy to seal your home properly when it is being built. All that is required is a knowledgeable general contractor who pays attention to details and a good set of construction plans.

We strongly recommend that the homeowner hire a certified energy auditor to review the construction plans and monitor the home while under construction, because he can test the home for tightness after it is completed.

Most states offer some type of financial reward if the home meets a certain energy standard and your energy auditor can help you with submitting the proper documents.

In short, your new log home needs to be air sealed very well, and it is easy to do with the help of an energy auditor.

Published on: December 8th, 2016

Should I consider solar panels for my log home?

If your planned log home location is in a highly remote area where bringing electricity in could be expensive or if you just want to be energy independent, solar panels may be the solution.

For one thing, huge, unsightly solar panels are a thing of the past thanks to new innovations such as solar thin film technology, which are sold in rolls and reduces cost in materials and installation.

Solar windows are another newer option for homes. Companies such as Solar Window Technologies are creating glazing that has been treated with an electricity-generating coating that is transparent but is able to convert sunshine into energy. And they claim that the return on investment for these windows can be as little as one year.

Then there are companies like Tesla — yep, the car company — who have taken the science behind the first commercially successful electric car and transferred it to create the Powerwall, an affordable, long lasting battery for residential use. These lithium-ion batteries collect the energy produced by the solar collecting panels and distribute it when there is no sunshine.

In addition to the long-term savings you can enjoy by generating your own electricity, there are more immediate financial advantages: The federal government offers a 30% tax credit for harnessing solar power, and almost every state has some other type of incentive, with the largest being Hawaii at a 35% tax credit.  Depending on where the home is located, you could see a return on your initial investment in half the time if you take advantage of these incentives.

These are just a few examples of how harnessing solar energy for log homes has become more practical, and less obtrusive, than ever before.

Published on: November 23rd, 2016

Should I consider radiant heat for my log home?

Radiant in-floor heating can be a fantastic option for a log home for several reasons.

First is efficiency. In a conventional forced-air system, heat is generated by a furnace and piped through a series of ducts, typically placed near the ceiling of a room. Since heat rises, the warmed air may have difficulty reaching the residents. This type of system also creates hot spots near the duct vent and cool spots farther away from the source, resulting in uneven temperatures even in small spaces. The same goes for differences between upper and lower floors.

Radiant in-floor heat, on the other hand, involves a system of coiled tubes that lie just below a home’s finished floor material, heating a room from the ground up. Whether the radiant system is electric or hydronic (water) based, this continuous system also allows for more even temps throughout the space.

And in terms of construction efficiency, it’s much easier to install radiant heat in a full log home’s floor than creating areas to run bulky ductwork.

Second is creating a better indoor environment. A forced-air system doesn’t just blow air – it propels all the dust, pollen, pet dander and other airborne contaminants right along with it. For people with allergies, this can present a very real and chronic problem. Not to mention that it deposits the dust around your home, and if you have round interior logs, that dust can settle and collect on top of them.

Without a blower to scatter these contaminants around the house, a radiant in-floor system can provide a cleaner, healthier indoor environment. And there are no noisy fans kicking on and off to disturb the peace.

And last, is the long term savings. It’s true that a radiant in-floor system likely will be more money (sometimes as much as double) in terms of up front costs than a forced-air system, but there’s quite a bit of long-term cost-saving to be had. A perfect example is that radiant heat’s “from the ground up efficiency” allows you to set temperatures at lower levels, saving on fuel and operational costs without sacrificing comfort. Even by conservative estimates, radiant heat can save 20 to 30 percent more energy than traditional furnaces, and some have seen annual savings in the 50-percent range. A slightly bigger investment at the onset could reap loads of comfort and financial benefits down the line.

Published on: August 18th, 2016


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