Day 48: Sustainably Heating Your Home Part I—Home Design And Improvement
Dear Student,
Over the coming few days we’ll discuss the various ways to heat a home sustainably. Of course, the less heat you need, the lower the cost of any heating system… and no matter which system you choose, there will be some annual maintenance costs, which you should be well informed on to ensure you select the best system for your needs.
In colder climates, heating your home can require a lot of energy. Traditionally in the parts of the world that got cold, the heat from animals was used to help heat homes. The ground floors of houses were given over to stables for livestock, and their body heat rose to the upper stories, warming the house above.
This is done in modern greenhouses to keep temperatures above freezing during the winter, though small livestock are generally used these days.
Few these days would be willing to give over part of their homes to animals as my great grandparents did on the coldest nights… but if you can completely replace your home heating system with a self-sufficient one, your home can be heated indefinitely at practically no cost.
Conserve And Insulate
The easiest way to slash heating costs is to reduce heating you don’t need and to conserve the heat you already have.
Conserve
Tips for conserving heat can seem like common sense…
If your home heating system can heat separate parts of the house, turn off the heat going to unused parts of the house. If not, turn down the heaters and radiators in parts of the house you’re not using frequently.
Gradually turn the thermostat down a couple of degrees and when cold, simply add a layer of clothing instead of turning up the heat.
Insulate
Old houses often allow most of the heat to escape before it can be enjoyed by the occupants.
Proper insulation of your home when it is built can reduce heating costs dramatically.
If you are buying or live in an already constructed home that is not well insulated, retrofit insulation. The expense is recouped in saved heating costs over just a couple of years.
Most heat escapes through a badly insulated roof, the second worst offender is usually walls, and single-glazed windows can lose a lot of heat quickly, too. Walls can be retrofitted with insulation in the form of panels or insulating foam that is pumped into the cavities in your walls.
Draughts and air leaks can also lose you a lot of heat… Ensure that only the necessary vents in your home allow air in, block cracks around doors and windows, and seal off where the roof joins the house with expandable insulating foam.
When insulating, remember to put down a vapor barrier to prevent condensation from the air in the house causing mold problems.
Building Strategies
Super-efficient modern zero-heat homes can retain all their heat with practically no heat loss. In houses like these (common in Scandinavia and Canada) the body heat of the occupants and the stove is enough to keep the house temperature warm and stable.
While the cost of this building style might be prohibitive, you can take some lessons from traditional housebuilding methods…
Enclosed porches or vestibules on houses can drastically reduce the amount of heat lost every time an outside door is opened. Add a tiny room outside your front door (or section off a space on the inside) that you step into when entering and exiting. This way, instead of all the heat in your house escaping out the front door when it’s opened, only the warm air in the small porch is lost. This conserves a lot of heat.
Similarly, as we cover in the chapter on greenhouses, building a greenhouse onto the south facing side of your house will heat the walls and reduce your energy consumption. We cover other aspects of design like this in the Climate Design lesson, including windbreaks and their effects.
Waste Heat Recapture
With a little thought, and especially if you are undertaking other off-farm endeavors like power generation or wood gasification, the waste heat from the engines or machinery can be redirected through your home to raise the temperature before it is exhausted as cool air into the outdoors.
There are also sophisticated heat-management systems that extract heat from the air vented from the house to allow fresh air in. These are particularly important in zero-heat homes, as there is no air getting into the sealed house except what little comes in through the vents.
Geothermal Heating
A popular strategy these days, the idea is based on the fact that even through it might be -40 degrees on the surface, six feet underground the soil maintains a consistent 55 degree Fahrenheit temperature.
To take advantage of this phenomenon, long coils of plastic tubing are run underground into a heat exchanger. The coils are filled with liquid that’s pumped around to gather the surrounding heat.
While 55 degrees sound chilly to many folks, this ambient heat can be concentrated with a heat pump to produce efficient underfloor heating.
Solar Space And Hot Water Heaters
These have become extremely efficient over the past few years and once installed require little maintenance.
They work best in warmer climates, however, and can supply large amounts of hot water each day for free.
Even in cold climates these can be good supplemental heaters and can supply some your hot water needs during winter. Some backup heating might be needed, though, especially during cold and cloudy weeks.
Solar heaters can be passive thermosyphon or actively pumped. It is feasible to make solar heaters at home, but the cost has reduced so much these days, and the modern systems are so efficient it’s really better to consult an installer before deciding to make one yourself.
Sustainably Heating Your Home With Wood
Since before humankind as we know it existed, we have been heating ourselves by burning wood…
Wood is a renewable resource and is carbon neutral, meaning that (if sustainably grown) wood burning doesn’t add more carbon to the atmosphere, as it used an equal amount of carbon from the atmosphere during its growth.
The calorific value you receive from firewood is related to the amount of carbon in it. Hardwoods have more carbon, softwoods have less. Wood are compared by the dry weight of the wood you have.
If you are lucky enough to have a wood lot on your farm or have access to a family member’s wood lot, you can supply all your heating needs easily.
Buying wood for burning can be expensive unless you find someplace to haul it from for the price of transport (like wood mills), but this option isn’t available to most.
If there is marginal oil on your property, you could plant a wood lot or fast-growing firewood trees on your property.
If you choose to grow your own wood, remember that you can’t take two much from a wood lot each year and remain sustainable. Moderate hardwood lots can supply two or three cords per acre per year and still be sustainable. A cord of wood is a pile 4 feet wide by 4 feet high by eight feet long. The actual amount of wood in a cord depends on the size of the timber pieces and how it is stacked.
Tips to improve and sustainably harvest firewood over several years:
- Cut up and use all dead trees on your property. This will open up space for healthy trees to grow into.
- Remove all diseased parts of trees. If the disease is too large to cut out of the tree, harvest the entire tree for firewood.
- Remove trees that have little value as lumber.
- Once the remaining trees have had space for their continued growth each year, harvest any mature trees you need for lumber. Use branches and waste wood for heat.
- Harvest any branches from timber or fuel wood trees that become damaged or are crowding out other valuable trees.
- Once established trees that had sufficient growth space are harvested, replant with either hardwoods or fast-growing fuel wood trees for the future. Some of these trees could be leguminous support trees. Or replace harvested trees with short-lived fruit trees that can be used for medium-term fruit production and future fuel use.
- Remember to keep an eye on the wood lot, if you harvest too much it will become too thin and bushes and other plants will creep in.
- To ensure cleaner and easier burning, store your firewood in a woodshed during the summer months to let dry.