EnviroCentre Edition - Spring 2016
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Catherine Mageau-Walker (SustainLowertown Coordinator), Annie Mercier (LCRC Community Developper), Mathieu Fleury and Angela Palma Herriot at a Good Food Market in Lowertown.
Photo courtesy of SustainLowertown
Energy Assessments Help You Renovate Smart
Bridget O’Flaherty and Greg Furlong (EnviroCentre)
A major renovation, such as finishing a basement, installing new siding or replacing the heating system is also a major investment. With continually rising fuel prices, more and more homeowners are considering how to reduce their energy bills while planning renovations. They want to know where energy savings can be added into their renovation plans prior to making large changes to their home. An energy assessment can provide this kind of valuable information, along with suitable recommendations for improvements.
Who performs an energy assessment?
A Certified Energy Advisor (or CEA) can guide the homeowner by conducting an energy assessment. Certified by Natural Resources Canada to conduct energy assessments, the CEA is trained and experienced in many aspects of the building industry. They look at a house differently than a building inspector or contractor, considering it as a system for providing comfortable, affordable and healthy shelter to its occupants, otherwise known as “home performance”.
What is an energy assessment?
As thorough as a buyer’s home inspection, a certified energy assessment provides a comprehensive analysis and understanding of a home’s energy performance, including current energy use and options for minor, major and deep retrofits for energy savings. The assessment includes measurements and calculations of a home’s geometry, detailed data collection on the building construction envelope and energy using systems, and a blower door test to measure air leakage. All of this information is used to create an energy model of a home using approved software. The results gleaned from this model can then be used to determine heat loads, quantify air leakage and understand indoor air quality.
A home’s energy usage is often solely attributed to its furnace. Although the type, efficiency and fuel used by a heating system are important factors, there is much more to a home’s overall performance. Compare this to a car, where performance is not just about the size and efficiency of the engine, but about many features working together: aerodynamics, acoustics, glazing, drive train, electrical system and driver behaviour all influence how a car runs. A home has similar synergies. First, there is the building envelope, which includes the roof, attics, ceilings, walls, windows, doors, foundations, floors and insulation as well as the home’s natural air change rate (i.e. how quickly the air leaves, taking heat with it). Then there are the high energy users (like the car’s engine): the HVAC (heating, ventilation and air conditioning) systems, water heater, lights and appliances. Finally, an occupant’s behaviour can have a big impact on energy consumption – similar houses often receive very different utility bills!
During the energy assessment, a home’s data is collected and a depressurization test is performed, providing not only the information needed to create an energy model, but also serving as a critical diagnostic tool for detecting major and minor air leaks and to assess indoor air quality. A home’s natural air change rate should be in a range that provides good indoor air quality and will determine how much added mechanical ventilation is required. A CEA estimates these air changes and makes recommendations to keep families comfortable and healthy.
How can an energy assessment guide a renovation?
Once an energy assessment is complete, a CEA identifies what needs attention, where to find the biggest gains in energy conservation, and how to prioritize upgrades among the building envelope and HVAC systems. For example, minor improvements, such as caulking, weather stripping and other airsealing, can often have a big impact on keeping the heat in and can be mostly done by the homeowner themselves. Larger retrofits, such as adding insulation or new windows, and deep retrofits, such as gutting, exterior insulation, re-siding, or adding a new heating system, will most likely require the assistance of a professional. After a home is properly sealed, it is important to determine the right sized HVAC systems to ensure a home’s overall comfort. This sizing can be based on the home’s performance as accurately determined by an energy assessment. Lastly, occupant behavior will always influence overall energy use, and a CEA can give homeowners tips on ways to conserve energy and save money.
A home is a place to feel safe and comfortable and renovations ensure these feelings last. Upgrading for aesthetic reasons may increase the overall value of a home, but including energy saving measures along the way increases it even more so. The advice received from an energy assessment increases a home’s ROI (return on investment) and keeps money in a homeowner’s pocket long after a renovation is complete.
To learn more about energy assessments or to take a workshop, please visit envirocentre.ca.
PERC thanks the above organizations for their support.
Thank you to Envirocentre for sponsoring the Spring 2016 edition of the PEN.