Transforming your older home into an energy efficient 'Net Zero' gem

Transforming Your Older Home into an Energy-Efficient Gem

Revitalizing older homes with modern energy solutions is an increasingly important retrofit for British Columbians who want to achieve net zero energy (NZE) – or at least “near net zero” – consumption. Net zero homes produce as much energy as they consume. Retrofitting older houses to achieve net zero energy is a pivotal step in the fight to reduce greenhouse gas emissions and ensure a sustainable future for generations to come.

Unlike conventional buildings that rely heavily on hydro-generated power and fossil fuels for their heating, cooling, and electricity, net zero energy houses utilize renewable energy sources to meet their energy needs.

Achieving net zero is important for older homes for several reasons:

  1. Reducing a home’s carbon footprint helps mitigate its environmental impact.
  2. Lower energy bills and potential government incentives can make the upgrade financially advantageous.
  3. The improved air quality, consistent temperature, and the elimination of drafts will enhance your family’s living conditions.
  4. A sealed, super-insulated home has significantly lower maintenance costs.

In this guide, we will explore various strategies and technologies that can help transform an aging property into an efficient, sustainable and comfortable living space.

Net zero vs near net zero

According to the Canadian Home Builders’ Association, “A net zero” home produces as much energy as it consumes. It has been designed and constructed for optimal energy efficiency and cost.” In the NAIMA Canada Guide to Near Net Zero Residential Buildings, “A near net zero building is one whose annual energy requirements are minimized and could be partially or completely offset by renewable
energy. Its energy use is reduced to very low levels compared to traditional construction by using energy-efficient design solutions for all aspects of the building.”

The difference between the two is how much of the home’s energy needs will be met by a renewable source of energy, and the target is generally determined by the cost and feasibility of making the required energy-efficient upgrades.

Assessing the current state of your older home

Before embarking on the journey to net zero, it’s important to first evaluate the current condition of your home. Older homes simply weren’t designed with energy efficiency in mind. Here are some key areas to evaluate:

Air sealing and insulation: Poor quality insulation, air leaks and thermal bridging are common in older homes, and that leads to significant energy loss.
Windows and doors: Old, single-pane windows and traditional wood doors can be major sources of heat loss and drafts.
Heating and cooling systems: Outdated HVAC systems are typically inefficient and very costly to operate.
Leaky air ducts: Older houses settle, the sealing tape on ducting can dry out, and some ducting may suffer from leaks or gaps due to improper installation. With less warm air entering the rooms, this causes people to raise the thermostat, leading to wasted energy and higher bills.
Electrical system: An older electrical system may not support modern energy solutions, or the many appliances and devices you plug in, safely or effectively.
Appliances and lighting: Old, inefficient appliances and lighting can contribute to high energy consumption and costly utility bills.
Toilets, faucets and shower heads: Older houses can waste a significant amount of water due to outdated fixtures, water pipes, potential leaks and inefficiencies.

A professional energy audit can help identify issues and provide a roadmap for improvements.

Enhancing the insulation and air sealing

Improving your home’s insulation and air sealing is a foundational step towards achieving net zero. Upgrading to effective, continuous insulation will reduce your need for heating and cooling, resulting in significant energy savings. Adding a layer of rigid foam or rigid stone wool board as continuous non-structural sheathing to the exterior, and dense-packing any cavities with cellulose or mineral wool, are a great first step toward meeting net zero standards.

Adding insulation to the attic is one of the most cost-effective upgrades, using blown-in cellulose or applying semi-rigid batts. Insulating the basement walls, headers and rim joists with rigid foam boards is another way to greatly reduce heat loss. Proper air sealing by caulking and weather-stripping around the windows, doors and other openings is crucial to prevent thermal transfer between the inside and outside of your home.

Upgrading the windows and doors

Installing triple-pane windows with insulating gas fills like argon or krypton is highly recommended for net zero retrofits. They provide superior insulation, with typical U-values between 0.19 – 0.26. Windows with Low-E (low-emissivity) can reflect heat back into the rooms during the winter, while blocking out unwanted solar heat gain in the summer, to reduce your heating and cooling loads. Ensuring airtight, thermally broken installation of the windows is crucial for preventing air leakage and thermal bridging that could negate the performance benefits of your new high-efficiency windows.

When it comes to doors, replacing those old, drafty exterior doors with insulated units is an important step in improving your home’s thermal envelope. High-efficiency doors will typically have a polyurethane foam insulation core and triple-pane glass inserts with insulating gas fills like argon or krypton, weatherstripping and tight seals to prevent air leakage. As with the windows, airtight, thermally broken installation is essential to prevent air leakage and thermal bridging.

Modernizing the heating and cooling systems

Upgrading to a high-efficiency heating and cooling system is essential for reducing your home’s energy consumption. Heat pumps use electricity to move heat from one place to another, providing efficient heating in winter and cooling in summer. Heat pumps can replace older, inefficient furnaces and air conditioners to reduce the energy load required to maintain a comfortable indoor temperature.

Smart or programmable thermostats can optimize your heating and cooling schedules, to reduce energy waste by keeping an empty house at the perfect temperature. They can also reduce the temperature automatically when everyone’s tucked into warm beds. Smart systems can learn your family’s occupancy patterns and make automatic adjustments to save energy while maintaining comfort.

Ensuring proper ventilation

An energy-efficient and airtight home requires proper ventilation to maintain the air quality indoors. Without air infiltration/exfiltration caused by air leakage in older homes, indoor air would become stale and accumulate pollutants like VOCs, odours, humidity, CO2, etc.

Ventilation systems like energy/heat recovery ventilators (ERVs/HRVs) exchange the stale indoor air for fresh outdoor air while recovering up to 92% of the energy from the conditioned indoor air. Heat recovery ventilators (HRVs) exchange the stale indoor air with fresh, filtered outdoor air, to improve your home’s energy efficiency. Energy recovery ventilators (ERVs) are similar to HRVs, but also retain moisture in your home during the winter, which can help maintain balanced humidity levels.

Upgrading electrical systems

Modernizing your home’s electrical systems may be essential to support new energy-efficient appliances, the many plug-in devices in a modern home, and smart and renewable energy technologies. Many older homes are in desperate need of additional outlets in each room, and an electrical panel upgrade can ensure that it can handle the increased load.

If you haven’t already done so, you should replace the incandescent bulbs with energy-efficient LEDs. LED bulbs use 25-50% of the power, compared to traditional bulbs, and they last longer, contributing to overall energy savings. A smart lighting system, with occupancy and motion sensors, can automatically turn lights on when someone enters a room and off when they leave, eliminating the unnecessary lighting of unoccupied spaces. Sensors can also detect ambient daylight levels and dim or turn off artificial lighting to take advantage of natural light.

Enhancing the appliances and water heating

Replacing outdated appliances and water heaters with Energy Star® certified models that use 10-50% less energy can significantly lower your energy consumption. You may also be eligible for appliance rebates through BC Hydro and FortisBC, under the CleanBC Better Homes and Home Renovation Rebate Program, which can reduce the upfront costs and payback periods.

Adding a renewable energy system

To achieve true net zero energy status, your older house must incorporate a renewable energy system. You’ve worked hard to reduce your energy consumption, and solar panels or wind turbines can generate clean electricity on-site, offsetting the remainder of your energy requirements.

Photovoltaic (PV) solar panels are the most common renewable energy solution for home upgrades in BC. Your solar panel system converts sunlight into electricity, reducing your reliance on the grid. BC Hydro’s net metering program is designed for those who generate their own electricity. Net metering allows you to power your home with renewable energy in a self-sufficient way but with the ability to rely on their grid if you need it.

The takeaway

Revitalizing older homes with modern energy solutions is not only feasible but holds great benefits for BC homeowners. By upgrading the insulation, installing high-efficiency windows and doors, modernizing heating and cooling systems, integrating renewable energy, and leveraging smart home technologies, it is possible to transform your aging house into a Net Zero Energy (NZE) or Near Net Zero home.

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