With the increase in fuel prices and utility costs, homeowners are looking for ways to reduce their energy consumption. Transitioning to a Net Zero energy home can reduce your energy cost and make your home energy independent. Net Zero energy homes are typically 80% or more efficient than an average new home and a lot more comfortable to live in. Net zero energy renovations, if done properly, can bring your energy bills close to zero. This blog will guide you through the basic steps involved in your net zero journey. When planned properly, you can undertake the transition in incremental steps rather than going in all at once – taking your budget and circumstances into account.
The first step on a journey to a net zero energy home, is to understand your home’s current energy usage. Getting an energy audit (i.e. EnerGuide evaluation) done will help you understand how your home is using energy and identify the upgrades which can reduce your home’s energy consumption. A registered energy advisor will inspect all areas of your home and identify any potential energy leakages and safety hazards. After inspecting your home, the energy advisor will prepare an EnerGuide evaluation report. This report helps you understand areas of improvement like your home’s insulation requirements, the heating & cooling load for your HVAC system, and the benefits of installing a Solar PV system to power your home.
Please feel free to refer to our blog “Energy Audits – the first step to saving money” for more information on the benefits of EnerGuide Evaluation
Cost: A pre-retrofit EnerGuide evaluation for a typical existing home can cost anywhere from $450 - $725 (depending on where you live) and an additional $250 - $595for a post-retrofit EnerGuide evaluation.
Once you get your EnerGuide evaluation, it is important that you address upgrades to your home’s building envelope first. Once all improvements are made to the building envelope you can ensure that the mechanical system upgrades are designed with the lower consumption in mind, saving you money.
What is a Building envelope?
Building envelope is what separates the inside of your house from the outside environment. It acts as a physical barrier and protects you from outside weather (wind, rain, etc.), temperature, noise, and UV radiation. For a typical home, the building envelope consists of outside walls, roof, foundation, windows, doors, insulation, and air/vapor barriers.
Steps to upgrade your Building envelope:
- Perform Air Sealing: Air sealing is the most cost-effective way to improve the energy efficiency of your home. It should be considered first in any upgrade strategy. Comprehensive air sealing involves identifying sources of air leakage and sealing them with weatherstripping and caulking and by applying gaskets and tapes. A blower door test, performed by professional contractors or energy advisors, can help you identify specific leakage areas. Key areas to look for air leakages are attic hatch, ceiling penetrations into the attic, doors, exhaust vents, mail slot, sills and headers, service entry, floor drains, foundation cracks, electrical outlets, windows and chimneys.
- Cost: The cost of air sealing a typical house depends on its size, extent of leaks and materials required to air seal them. Costs generally vary from $600 to $1,000.
- Adding Insulation: The efficiency of the building envelope is strengthened significantly by adding effective insulation. It acts as a barrier between your home and the outside environment and significantly reduces the energy consumption of your home. In Canada, net zero energy homes generally require significantly more insulation than conventional homes. But, on the brighter side, net zero energy homes require just half the energy to heat a conventional home. The effectiveness of insulation is measured by its ability to resist the flow of heat. This thermal resistance is expressed as R-Value. R-Value of insulation depends on the area of the house in which insulation is being installed and the local climate. In most regions of Canada, it is recommended to have the following R values
Location Effective R-Value
Roof (with Attic) R-60 – R-100
Above-Grade Wall R-30 – R-70
Below-Grade Wall R-22 – R-40
Floor Slab R-10 – R-40
- Cost: The cost of insulation depends of the size of the home, accessibility of areas to be insulated, existing insulation, type of insulation and R-value of insulation to be added. For a typical 2,000 sq ft home, it could cost between $8,000 to $13,000 to insulate the attic/ceiling, walls and floor slab.
- Installing triple-paned Windows: Windows are an integral part of your building envelope. Replacing your existing windows with ENERGY STAR® certified triple paned windows will allow less heat to escape, have less condensation, and make your home soundproof. For a net zero energy home, it is ideal to have windows with an R-value of 7 – 8 and a U-factor of less than 0.25. Triple paned windows are 50% more efficient than double paned windows.
- Cost: The cost of windows depends on the location of installation and the style and size of the windows. Cost of a small energy-certified triple-paned window varies from $400 - $1,000 depending on the style of window. The cost of a medium-sized window varies from $600 - $1,300. Large windows can cost from $1,000 - $2,000
Moving away from fossil fuel-based mechanical systems to electric systems is the next step in your journey towards a net zero energy home. One of the biggest benefits of improving your home’s building envelope and air tightness is that your house requires significantly less energy and so you need significantly less sized mechanical systems. Here are two most important mechanical systems you can consider upgrading:
- Heat Recovery Ventilator (HRV): Since your home is now airtight and sealed, you will need a heat recovery ventilator to continuously replace stale indoor air with fresh outdoor air. During the heating season, the HRV captures heat from the stale air leaving your house and uses it to preheat the fresh air coming into your house. Similarly, an HRV can reverse this process during the cooling season, removing some of the heat from the incoming air and transferring it to the outgoing air. It is recommended to use only highly efficient ENERGY STAR certified HRVs to save maximum energy. Also, it is suggested to install HRVs as soon as you are done upgrading your building envelope as a closed envelope does not allow air ventilation and can lead to health and safety issues for occupants.
- Cost: The cost of a residential HRV air exchanger unit range from $750 to $2,500 with an average cost of $1,200.
- Electric Heat Pump: Transitioning to an electric heat pump and air conditioner is the final step in upgrading your mechanical HVAC systems. It is important to know your new heating and cooling loads before finalizing the size of the system. You can use an air source heat pump or geothermal heat pump. Air source heat pumps move heat between the air inside a home and the air outside the home, while ground source heat pumps (known as geothermal heat pumps) transfer heat between the air inside a home and the ground outside a home. It is recommended to use Natural Resources Canada (NR Can) recommended ENERGY STAR certified heat pumps for maximum savings
- Cost: The costs of heat pumps depend on their size and efficiency. Typically, it varies from $7,000 for small homes and about $16,000 for larger homes.
Besides the above-mentioned steps, you can also ensure more energy savings by using energy-efficient lighting fixtures and appliances.
It is also recommended to engage a net zero energy consultant that can create a customized renovation plan for your home and help you chart your path to a net zero energy home.
Saaf (your hub for green home improvements) will help connect you to qualified energy advisors, net zero energy consultants, and other contractors in your area and help you make informed decisions by understanding your needs, exploring federal and provincial rebates, getting you quotes from contractors in your area and showing you your savings from rebates on those quotes at no cost to you! Come check out our website and start your journey to savings and a better home with us. To learn more visit our FAQ page, contact us, or write to us at contact@saaf.io.
Stay tuned for our next blog on possible rebates and zero to low-interest financing options for your net zero renovation!
