Needless to say, our ancestors didn’t care too much about heating their log cabins. Large fireplaces had no problem heating one or two rooms in which they lived. Of course, now that log homes are family-sized, people are often under the impression that there is something different about the way they are heated, and the good news is that a standard system will work just as well in a log home. logs as in a traditional structure.
Almost all log houses are built with at least one chimney. Initially we thought our beautiful soapstone wood stove would heat the entire house and we would use our forced air propane heat for backup. Unfortunately, we were all wrong. Because we have a cathedral ceiling with a large loft, the heat from the stove goes directly upstairs, requiring two ceiling fans to recirculate the hot air. We expected this, but we also thought that the heat would spread sideways into the rest of the open space (dining room and kitchen). Not in your life! Even sitting on the couch about 15 feet from the stove, I need a quilt. I am uncomfortably cold in the kitchen. I think if we had a regular ceiling, the heat might have gone where we expected, but the volume of the cathedral ceiling messed up our calculations. Also, the soapstone stove is designed to run 24/7, and because we both work for a living, the stove doesn’t come on until evening. This wood-burning stove needs to heat up slowly at the risk of cracking the stone, so that when it’s actually cooking, we’re ready for bed.
Old fireplaces traditionally sucked in all the hot air in the room, but modern designs are more efficient at recirculating heat. The most energy efficient chimney is built in the center of the house, so that the heat from the chimney is not lost to the outside. Outdoor fireplaces can create drafts if the fire is extinguished, making it more difficult to start a new fire. If you are planning multiple fireplaces, placing two of them back to back (facing adjoining rooms) will give you the opportunity to build a fireplace with two flues. Or you can put a chimney over your oven, again allowing two flues in the same chimney. A direct vent fireplace will eliminate the chimney, but you’ll have to figure out how to hide the vent in the outside wall. Or, if you’re using a wood stove, you can run the pipe through the wall and straight out, building a box around the pipe to simulate a fireplace. Depending on the look you want, you may want to leave the pipe inside the room and send it through the ceiling. This will give more heat.
It’s a good idea to consider your heating and cooling needs early in the design phase. Although log houses are naturally energy efficient, it is not advisable to skimp on your system. You may be able to heat your entire home with a large fireplace or wood stove, but the municipality will likely have minimum standards to meet before issuing a building permit. Also, you need to consider the resale value. I know of one person who tried to sell a million-dollar handmade log home with no oven, and as you might suspect, the buyer never showed up. The house was listed as unfinished, and installing the heating system after the fact was too daunting a task. A similar problem exists if you try to escape without central air conditioning. Yes, log homes stay cooler in the summer, but those August “dog days” can give you a perfectly miserable night’s sleep, and a potential buyer probably won’t be as forgiving as the original owner. In fact, our mortgage company wouldn’t even consider a construction loan if we didn’t include central air conditioning.
If you want to conserve duct space, you can use forced air heat, with the same ducts serving the air conditioner. Propane or oil are often the fuels of choice in rural areas. If interior wall space is limited, there are companies that specialize in very small high pressure duct systems that fit into tight angles; these systems generally require a much higher initial installation cost. When using traditional ductwork, you want to keep angles to a minimum, so it’s helpful to design first floor walls that will conveniently carry air directly to the second floor. An open floor plan offers a challenge, because you have to keep in mind that rooms above you need to be heated in some way, and you’ll need supply and return vents to create efficient airflow. If you want to use full log interior walls, you’ll have to find another way to run the ductwork, electricity, and plumbing. We made that mistake and there are not enough vents in our bedroom. The air is stale in the summer, even with the windows open.
Where do the winds go? Since all of our exterior walls are lined with logs, many of our vents were placed on the floor. If your interior walls are drywall or tongue and groove, you can place the vents where they normally go. One thing I wish I had done was go over the plan with the HVAC contractor, because he put the vents in the places I thought were the most inconvenient. Sometimes it can be avoided, and sometimes it cannot.
If you’re concerned about energy and prefer to leave your thermostat all the way down, you’ll find that the south side of the log home tends to be warmer than the north side. Because the sun tends to sink closer to the horizon on a winter afternoon, it is advantageous to place large windows facing south; During the summer, the sun will come through the roof, so it won’t overheat your house. However, you may find that the north side of your house, which receives no direct sun at all, could be noticeably cooler. The best solution is to install underfloor heating (if you can afford it). Although this system requires a boiler instead of a furnace, underfloor heating distributes heat evenly throughout the house, eliminating north-facing blues. With underfloor heating, you have to keep the thermostat stable all the time; the system is not designed to turn off when you go to work. In addition, you can also use the boiler to heat hot water, eliminating the need for a hot water heater. On the other hand, you will still need to install ductwork for the air conditioning.
In general, the same considerations apply as in normal construction. We thought we could get by with a single heating and cooling zone, but in hindsight, two zones would have solved a lot of problems. In the long run, it’s cheaper to do it right in the first place. Retrofitting a log house is not going to be a piece of cake!