This guide is for anyone interested in using energy more sustainably in their building projects. It will give you an overview of the most effective and widely available methods of making buildings “greener” when it comes to energy.
We’ve divided it into two major sections so you can consider both how to power your building and how to use that power wisely once it’s connected. Section I focuses on alternative renewable energy sources you can incorporate into your building project. Section II walks you through some strategies to reduce the amount of energy your completed project will use.
The guide is geared more towards residential projects than large commercial or public projects, although the information applies across the board. Further resources are included in each subsection if you want to pursue more technical information about any of the subjects.
I. Alternative Renewable Energy Sources
One of the most important aspects of sustainability to consider in a building project is where the energy that will power the completed project will come from. Both new builds and renovations offer opportunities to shift energy sources from conventional, fossil-fuel-based energy to cleaner energy sources. Here are the most common clean options.
Solar Energy Systems
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Solar power systems typically use an array of solar cells to turn sunlight into electricity. Systems readily available on the market include photovoltaic (PV) panels mounted to a roof or to a ground array, but a few other options for solar power exist as well.
Building-integrated photovoltaic (BIPV) systems incorporate thin-film solar technology into building components like roofs or facades. Solar roofing is the most widely available and practical option for residential homes. Solar roofing materials include conventional-looking shingles or roofing tiles. These can be installed like conventional roofing materials and hooked up to the grid or to a battery bank.
A third, less common option, is solar thermal conversion. As the name implies, solar thermal technology converts solar radiation into heat. Collectors absorb the sun’s rays and transfer that heat to carrier fluid that runs in tubes from the collectors to a building’s HVAC or hot water system. Although solar-thermal-electric conversion is on the rise, thermal conversion is typically used nowadays for domestic heating and water heating.
Pros, Cons and Considerations
Since solar systems are becoming more common, they’re also becoming easier to find and cheaper to install. Solar is a flexible option, with different sizes and types of systems available depending on your needs and budget.
The productivity of any solar system depends on its size. If you have limited space for a solar array, your energy production will likewise be limited. Site location is also a primary determinant of how much power you’ll be able to produce.
If your area doesn’t get a lot of clear weather, or if you have a roof that’s not oriented to take best advantage of the sun’s rays (eg. facing south if you’re in the northern hemisphere), you can still use solar technology—it might just take longer to recoup your financial investment.
Solar systems can be off-grid or tied to the utility grid. Off-grid systems are ideal for those in remote locations, but require the use of a battery bank to store energy. Those with access to utility grids might want to consider tying the system in.
Currently, all provinces and territories in Canada offer net-metering, which allows system owners to send any excess power produced back to the grid for credit. Credit is applied to energy bills when solar yield is low and the system needs to draw additional power from the grid.
With a grid-tied system, uneven power production is less of an issue, although going off-grid means you won’t be affected by power outages that affect regular utilities.
A Note on Batteries
People considering installing solar systems for environmental reasons should be aware that there’s a debate about the environmental friendliness of the technology itself.
Batteries are of particular concern (for both solar and wind systems). Producing batteries to store clean energy requires some not-very-eco-friendly practices and materials. Mining lithium, for example, is energy intensive and especially water intensive. A 2017 UT Austin study found that storing solar energy in batteries “actually increases both energy consumption and emissions” compared to grid-tied systems. And recycling batteries when they reach the end of their lifespan can be difficult, not least because of the toxic components involved.
This is not to deter you from using batteries to go off-grid, but to illustrate that as alternative renewable technology develops, we will also need forward-thinking public policies and practices to address gaps and ensure we’re not trading one set of environmental concerns for another.
Further Reading:
- The National Renewable Energy Laboratory (NREL) has a PVWatts Calculator that estimates PV system cost and production here.
- We compare grid-tied and off-grid DIY PV systems here.
Wind
Wind power, or small wind electric systems, power a home by using wind to turn the blades of a turbine, which connects to a generator that converts that rotational energy to electricity. Like solar systems, wind turbines can be grid-tied or off-grid. Off-grid wind systems can also use battery banks to store excess energy.
Not all wind turbines need to be giant structures, but the height of the tower and the diameter of the turbine’s rotor will determine how much power you can produce. At the very least, you will need to ensure that the turbine is mounted above any significant obstructions (“30 feet above anything within 300 feet,” according to Energy.gov).
Pros, Cons and Considerations
Properly installed, wind turbines are long-lasting and durable. If you live in an area rich with wind resources, a turbine can provide you with a stable, clean energy source. Small wind electric systems pair nicely with solar panels to compensate for uneven weather patterns.
Space is a big consideration here. The key to success with wind turbines is appropriate site selection, which rural homeowners will have more flexibility with. Towers can be free-standing or guyed, and guyed towers, which are less expensive to install, need room for the lines.
Wind is variable, so the amount of power you can generate will be too. Research into your region’s average wind speed is essential, as is research into the appropriate size of turbine for your particular site. Local bylaws might hold you back as well—not every area will permit a turbine.
Further Reading:
- WINDExchange offers this comprehensive small wind guidebook.
- The Canadian Wind Energy Association features this list of links to provincial information on sending energy back to the grid.
Geothermal (Ground Source Heat Pumps)
Geothermal energy systems make use of the constant sub-surface temperature of the Earth to heat and cool homes. The systems work much like refrigerators do, with refrigerant and water being pumped down into the earth in pipes. The ground will either warm the liquid (in winter) or cool it (in summer). The heated or cooled liquid is then distributed either through radiators or through a conventional forced air system.
Geothermal systems are usually installed either as a vertical closed loop system that’s bored straight down into the Earth or a horizontal closed loop system that creates the same effect with pipes buried in a grid pattern or in loops at a depth of 6-10 feet.
Pros, Cons and Considerations
To start with the cons, cost can be a prohibitive factor with installing geothermal energy systems. Vertical closed-loop systems require a drilling rig to reach the necessary depth of 300 to 600 feet, so the initial cost outlay can be difficult to recoup.
Horizontal closed loop systems are less expensive to install, but require a large area to lay sufficient pipes. Digging the trenches for the pipes is intensely disruptive and many homeowners won’t have the area necessary to lay them.
Once installed, though, geothermal is an inexpensive and low-maintenance system to run. In addition to being clean energy, geothermal is significantly more efficient than other methods of heating and cooling (200-300% efficient, according to Manitoba Hydro, compared to high-efficiency gas furnaces, at 92%). These systems are quiet to run and run less intensively, providing a more even heat source. They’re also very long-lasting, and function as both furnaces and air conditioners in one.
Further Reading:
- We discuss geothermal energy more extensively here.
- In this article, Mike Reynolds at Ecohome considers the cost-effectiveness of geothermal systems.
Biodiesel
Biodiesel is fuel produced from a combination of alcohol and oils such as vegetable oil or animal fats. The process results in a clean-burning oil that’s biodegradable. The oils can be new or used, with recycled grease making a fuel with a much lower carbon footprint. We commonly hear about biodiesel’s use in vehicles, but it can be used as an additive to home heating oil as well. It’s typically added to conventional fuel oil to create a blend containing between 5 and 20% biodiesel.
Pros, Cons and Considerations
Those with oil furnaces might find biodiesel a logical way to cut down on their fossil fuel consumption. It’s easy to add to oil tanks and won’t require anything new in the way of equipment or maintenance.
That said, biodiesel is a solvent, so more careful monitoring of system components like rubber seals is a must. On the downside, biodiesel is more expensive than other types of fuel and can be difficult to find.
Biodiesel comes with a distinct set of ethical issues to consider regarding food security. While the industry is developing cellulosic biofuels (biofuels made from plant materials that aren’t edible), currently, biodiesel is typically made from food crops like soybeans. Demand for those crops across sectors has led to an increase in food prices at a time when 1 in 8 Canadian households struggle with food insecurity.
Further Reading:
- Natural Resources Canada (NRC) offers this in-depth information on biodiesel.
- Greg Pahl at Mother Earth News explains how to heat your home with biodiesel here.
II. Saving Energy
Regardless of where your energy comes from, incorporating strategies to use less of it is a cornerstone of any green building project. In this section, we offer some suggestions for areas to focus your energy-saving strategies on, as well as ways to decrease your project’s ongoing energy use.
The Building Envelope
In Canada, almost “60% of the average household energy bill is used for heating,” says the Centre for Energy Advancement through Technological Innovation (CEATI). That makes an efficient building envelope, as CEATI states, “a critical aspect of the house’s energy performance.”
Heat loss is a significant waste of total household energy, but there are a range of ways to both prevent and address it. Tobias Roberts of Rise explains that heat loss in homes can be broken down as follows:
- Walls (35%)
- Windows and Doors (25%)
- Attics (25%)
- Basements and Floors (15%)
Keeping heat in the home depends on effective air sealing, minimal thermal bridging and adequate insulation. New construction projects have the best opportunities to ensure that homes are properly sealed with air and vapour barriers, that walls are constructed such that framing materials don’t create thermal bridges in the envelope and that attics, walls and basements are insulated at least to local minimum building codes.
Renovation projects could be more limited because some efficiency measures might not be practical or even feasible. That said, any simple efforts like caulking windows and weatherstripping around doors can make a difference in energy performance.
Consider having an energy audit done to give you more specific direction about how to maximize your home’s thermal performance. An energy audit is the best way to track down where heat loss is occurring and where to focus renovation efforts.
Further Reading:
- CEATI’s guide to energy efficient housing can be found here.
- This information about EnerGuide home energy evaluations explains the energy audit process.
Appliances
Natural Resources Canada states that appliances “account for 13.6% of the energy used” by Canadian households, so there’s an opportunity here to make a meaningful dent if you’re purchasing new appliances for your home.
All new appliances must meet minimum energy performance requirements in order to be sold in Canada. For high-efficiency appliances, ENERGY STAR-certified appliances are the standard, and looking for the ENERGY STAR sticker is an easy way of selecting new high-performance appliances.
The energy savings with ENERGY STAR appliances are sizeable. Certified refrigerators use 10% less energy than their non-certified counterparts, for example. Washers use 25% less energy and 33% less water.
Not every type of appliance is eligible for certification with ENERGY STAR, however. Cooking appliances (including ranges, ovens and microwaves) as well as combination washer-dryers aren’t certifiable. That’s because they’re already highly energy efficient, with little variation between comparable models and no real way to create a high-performance category.
With most of these appliances, you can use the EnerGuide label to learn about their efficiency. The EnerGuide label is mandatory on major electric appliances like ovens and combination washer-dryers, but voluntary for gas ranges.
The EnerGuide label tells you how much energy an appliance uses per year, as well as where the appliance sits in comparison to other models in its class. EnerGuide is easy to use—a lower number means the appliance is more efficient.
Further Reading:
- NRC offers this energy cost calculator, which gives you the lifetime energy cost of any new appliance you’re considering. They also offer this ongoing list of products that have earned ENERGY STAR’s “Most Efficient” designation.
- ENERGY STAR features this neat calculator, which estimates how much money you would save by replacing your fridge with a certified model.
Lighting
When it comes to reducing the energy used by lights, think daylighting. Daylighting is simply the practice of using natural light to reduce a building’s reliance on electric lights. Specific daylighting strategies run the gamut from easy solutions like moving a work desk under a window all the way to extensive systems that redirect and focus daylight.
To make the most of this strategy, incorporate it into your design and planning from Day 1. With new builds, lighting considerations can inform your site selection and building design, and you’ll have better opportunities to choose window configurations and make decisions about interior spaces with light function in mind.
With renovations, you’ll be more limited in how you can respond to the light resources available to you. Installing skylights or additional windows is a simple way to add daylight, but it’s important to weigh the cost (both financial as well as the cost to the thermal efficiency of a building) against the potential benefits. Just being savvy with paint colour, reflective surfaces and furniture placement can make a room brighter without incurring additional costs.
In terms of electric lighting, your most efficient choices will be LED or CFL bulbs. Either will be miles ahead of incandescent lighting in terms of efficiency (about 75% more efficient). There are a few drawbacks to CFL bulbs, though. The biggest is that they contain a small amount of mercury; not enough to harm anyone should they break, but proper disposal is essential. CFLs also can’t be dimmed and don’t work well as recessed lights.
LEDs last about 25 times longer than incandescent bulbs and 2-4 times longer than CFLs. They might be more expensive upfront, but they easily recoup their cost.
Further Reading:
- Architect Gregg Ander goes into detail on daylighting in this guide.
- Designer Patricia Davis Brown shares these design tricks for natural lighting.
Smart Technology
Various smart technologies are available on the market to help you monitor and trim your energy usage. Their manufacturers will tout their ability to save you energy and money. Their actual ability to do so will depend on factors entirely outside of manufacturer control.
Smart thermostats, for example, may or may not save energy. If you have a non-programmable thermostat, but diligently turn your thermostat back before bed each night and before you go to work, the benefit of the smart thermostat wouldn’t be energy saving so much as automation. And a regular, programmable thermostat would also provide that benefit.
That said, smart technologies can provide you with data about your energy usage—data you can use to make other energy-saving changes to your home and track their effectiveness. As in other areas, the technology itself doesn’t provide the benefit. The benefit is in how the humans use it.
Further Reading:
- ENERGY STAR features some smart home tips in this guide.
The Human Element of Energy Saving
The choices we make in our day-to-day activities play an enormous role in adding to our energy bills or decreasing them. We already know to turn off lights when we’re not in the room and to unplug appliances we’re not using, but to close, here are some specific suggestions for reducing your energy usage as you’re completing your green building projects:
Wherever possible, use natural energy that’s already at hand. Work during daylight hours to minimize your need for artificial light. Complete whatever tasks you can outside and take advantage of the breeze to reduce your need for fans. Reduce your need for space heaters by building or renovating in the spring and fall instead of winter.
Plan your trips to building supply stores to minimize the energy associated with transportation. You can carpool with someone else who has things to pick up at the hardware store or combine your supply trip with a trip for groceries.
Finally, be mindful of the energy your tools need. Unplug them when not in use and when you can, opt for hand tools for smaller jobs. Your human energy might not feel renewable and sustainable at times, but it really is.
Feature image: Julian Paolo Dayag; Image 1: Pixabay; Image 2: Skitterphoto; Image 3: Paolo Chiabrando; Image 4: Lisa Fotios
