When it comes to cabins, many people dismiss the need for energy efficiency. After all, it may experience only occasional use, and its principle heat source may be a wood-burning stove or fireplace — hardly a candidate for extreme energy-efficient construction.
But as energy costs rise and concerns regarding fossil-fuel use increase, there are a number of reasons to consider the energy efficiency of even the humble getaway cabin.
The energy to power your cabin and the systems it powers have often been overlooked in cabin living. However, rising fuel costs are having an impact on even weekend retreats. Time invested in planning and maintaining your cabin’s energy systems often mean the difference between enjoying time spent and sweating (sometimes literally) the cost of operating it. The good news is energizing your cabin efficiently doesn’t have to be complex.
There was a time when cabin power meant a windmill to pump water, and a wood-burning stove or fireplace to provide heat. However, the needs of today’s cabin dwellers call for more reliable, consistent sources of energy. (It’s hard to power a refrigerator or well pump with a bicycle generator.) When temperatures plummet, a small wood-burning stove will eat firewood as it struggles against invading cold air unless the cabin’s shell is well-sealed.
The recipe for an energy-efficient cabin has two parts: an efficient building envelope and efficient mechanical systems. It’s important to understand, though, that cabins are different than homes when it comes to energy and energy efficiency. They have different energy needs and different schedules for energy use. In some cases, you can treat your cabin just like your home, but often, this will result in spending more than you need upfront, paying additional operating costs and not seeing the benefits you would get if you were doing the same things in a home.
Seal the Deal
If you are building a cabin, use good double-pane log cabin windows, and seal windows and doors well. If you have an older cabin with single-pane windows or metal frames, consider adding storm windows.
The best place to seal your cabin is on the exterior surface of the wall to stop air and water before they have a chance to get into the wall, providing the opportunity to travel a considerable distance before working their way inside. When you seal, pay close attention to the intersections between the walls, roof and floor; generous use of caulk will pay large dividends here. Seal well between logs as well. Many log providers include caulk with their packages.
If you are working with an existing cabin, caulk and seal as much as possible between logs and where the wall meets the roof and floor. This can be a challenge in an older cabin. If the space between logs is large, install foam backer rod (rolls of rope-like foam) before caulking. This improves the seal while reducing the amount of caulk you need considerably.
Low-expanding spray foam works well around windows and doors. Use products designated as low expanding; regular expanding foam can distort door and window frames, and make units difficult to operate.
Cabin roofs are a major source of energy loss. If your cabin has an attic space, consider blowing in a thick blanket of cellulose, or adding fiberglass or rock wool. You can rent insulation blowers from big-box building supply stores.
Be sure to seal around chimneys and roof vents. If your cabin has cathedral ceilings, it’s more difficult to add insulation. However, many log homes with vaulted ceilings have rigid foam in the roof system, which provides excellent insulation as well as air movement blockage.
The process of tightening a cabin is similar to that for a log home. But when it comes to energizing, heating and cooling your cabin, the choices can be quite different. Start by considering your circumstances:
- How will the cabin be used — seasonal, weekend, future retirement?
- Do you plan to leave it stocked and ready for use so you can walk in the door and settle right in to your cabin?
- Do you foresee a day when your cabin might become your permanent residence?
- From where will the energy for your cabin come?
- Do you have municipal or community power available, or are you located beyond the grid?
- Are water and sewer already available, or will you have to provide these?
- What is your budget?
If your cabin is located off grid, it may cost more to bring in municipal power than to install something self-contained such as a small solar or wind system. Your budget also can affect your choice of heating, cooling and water-heating systems. Budget is not simply a matter of how much you have to spend but rather how much you want to spend to achieve a certain level of comfort. Your climate will play a role in this, too. You’ll have different heating and cooling needs in a high-elevation mountain setting than on a lake or ocean, or in a desert.
There are three basic ways to power a cabin: utility company, generator or battery. Utility power means a monthly bill based on usage. In remote areas, it may also mean bringing power lines a considerable distance at a considerable expense. If your building site doesn’t have utility power, weigh the costs of renewable energy systems such as photovoltaic panels and wind turbines. Prices of small systems have fallen significantly in recent years, making them more affordable than extending utility power over long distances, and are expected to fall more.
Generators can certainly power a remote cabin, but if you use a lot of electricity, expect to pay a hefty price for an appropriately sized generator. And with fuel costs rising rapidly, powering a cabin entirely by generator is becoming a costly undertaking.
If your cabin will not be tethered to the electric grid, and you don’t have the finances or desire to install a large generator, the remaining choice is battery power. The batteries used to power a home are different than a typical auto or boat battery. Home power batteries are designed to have a lot of power drawn from them and to be recharged many times over their life. It takes a number of batteries to power most cabins; a bank of 12 or more isn’t uncommon.
Usually the power from the batteries is run through an inverter that converts the batteries’ direct current to alternating current. Small cabins may be able to skip the inverter altogether and run entirely on direct current much like a motor home or travel trailer. Living off such power means two things: forecasting your electrical needs accurately, and having the right number and type of batteries, along with a charging system.
In addition, unless you have a hefty bank account, you’ll need to use electricity very conservatively. A typical microwave or space heater draws 1,200 to 1,500 watts of electric power, while an air conditioner may draw several times that. To your batteries, turning on one of these energy guzzlers is akin to handing a child a milkshake and a straw.
Most people living off grid start by simplifying their electrical needs. Some major appliances — such as refrigerators, stoves, water heaters and clothes dryers — can run on propane, which lowers your electric demand considerably. Instead of ceiling lights, use lamps that can be turned on only as needed. Read labels on appliances, and make your selections based on power consumption.
Batteries, of course, discharge, and recharging them is usually handled by a generator, an array of solar panels, a wind turbine or some combination of these. The design and sizing of solar and wind power systems calls for professional expertise, or a lot of self-education.
Heating and cooling, and heated water supply will be the largest uses of energy in your cabin. Doing these efficiently will save money while maintaining a high comfort level.
Here, cabins are different than primary homes because their needs and purpose are usually different. Cabins can often skip more elaborate, expensive central heating and cooling systems, and rely on simpler, decentralized systems such as wood-burning or gas stoves, and fireplaces. A well-designed, well-insulated and sealed 1,600-square-foot cabin can easily be heated by an efficient wood-burning stove with some low-power fans to circulate air. If necessary, small wall-mounted propane heaters can provide supplemental heat to bedrooms and baths.
Ductless heating and cooling systems similar to those used in motel rooms work well in larger cabins. Generally, the expense of geothermal or radiant floor systems isn’t necessary unless the cabin is large, poorly insulated and occupied often.
Tankless hot-water heaters work well in cabins. They take up little space and provide plenty of hot water in most circumstances. If your cabin is predominantly for weekend use, a tankless unit works especially well because hot water will be available the instant you arrive.
Is your cabin located in a freezing climate? Will it be left unoccupied for long periods? If so, you’ll need to weigh the costs and benefits of draining pipes when freezing is a threat versus keeping pipes and interior temperatures above freezing even when the cabin is unoccupied. If you want to avoid draining pipes, you’ll need a well-insulated, sealed cabin shell and a heating system that can be left on its own for long periods. Because you only need to keep the inside temperature above freezing, small electric heaters work well and don’t involve an unattended flame in your home.
Jim Cooper, a former general contractor, is author of Log Homes Made Easy and The Log Home Project Planner. He is a member of the U.S. Green Building Council and a LEED Accredited Professional who consults in energy-efficient and sustainable building. He can be reached at firstname.lastname@example.org.