Heating and cooling your log home
Needless to say, our ancestors didn’t care too much about heating their log cabins. The large fireplaces had no problem heating one or two rooms in which they lived. Of course, now that log houses are family-sized, people often get the impression that there’s something different about the way they heat themselves, and the good news is that a standard system will work just as well in a log home. trunks 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 whole house and we would use our forced air propane heat as a 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 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 roof, the heat could have gone where we expected, but the volume of the cathedral ceiling threw our calculations off. 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 the evening. This wood stove needs to heat up slowly at the risk of breaking the stone, so that when it’s actually cooking, we’re ready for bed.
Old fireplaces traditionally sucked all the hot air out of the room, but modern designs are more efficient at recirculating heat. The most energy efficient fireplace is built in the center of the house so that the heat from the fireplace 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 fit a chimney over your furnace, again allowing for two flues in the same chimney. A direct vent chimney will eliminate the chimney, but you will have to figure out how to hide the vent in the exterior 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 chimney. 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 homes are naturally energy efficient, it’s not wise 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 should consider the resale value. I know of someone 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 consider making 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 petroleum 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-story walls that will conveniently carry air directly to the second story. An open floor plan offers a challenge, because you have to keep in mind that the rooms above need to be heated somehow, 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, electrical, and plumbing. We made that mistake and there are not enough vents in our bedroom. The air is stale in 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 plaster 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 can’t.
If you are energy concerned and prefer to leave your thermostat on the minimum, you will find that the south side of the log home tends to be warmer than the north side. Since 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 go through the roof, so you won’t overheat your house. However, you may find that the north side of your home, which gets 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 steady all the time; the system is not designed to be turned 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 just one heating and cooling zone, but in hindsight, two zones would have solved a lot of problems. It’s cheaper in the long run to get it right in the first place. Retrofitting a log house is not going to be a piece of cake!