Do you have clients who want to lower their energy bills, save money, reduce their home’s environmental impact, greenhouse gas emissions, or improve the indoor air quality and make their home more comfortable?
Making a home energy efficient is the solution to dozens of challenges your clients face. Using less energy is just the start of it.
Whether it’s moisture control, improving air tightness and ensuring a fresh air supply to an existing house, or a push right to Net Zero homes, it's time for you to get on this bandwagon.
Here’s a brain dump on the top ways to improve your new home and renovation work by incorporating best practices to make your mark as a provider of energy efficient homes.
Must Haves for Energy Efficient Homes in Canada and the Northern U.S
Long, cold winters in North America require energy-efficient homes that reduce costs while still keeping families warm and comfortable. Thermal bridging is a significant source of heat loss - adding insulation can help minimize it but that's not all you need to do. For example, air sealing and cost effective outboard insulation go together as one package to create Energy Star and Net Zero homes. A good thermal envelope works both ways - keeping heat out in the summer.
Your building code may already require a higher performance building envelope, with reduced thermal bridging and an air tightness target. Heating and cooling (as well as water heating) equipment and all major appliances should be Energy Star certified products to keep home energy use and greenhouse gas emissions associated with energy use as low as possible.
That's just the beginning.
Building Codes and Energy Efficient Homes
In Canada, the National Building Code (NBC) aims to boost the energy efficiency of the construction sector to Net Zero Energy by 2032. Working to energy efficient targets in the tiered National Building Code, or the BC Energy Step Code, builders can select material and methods that are cost-effective and make an efficient home. An ENERGY STAR certified home offers several benefits, including:
- Being about 20% more efficient, practical, and cost-effective
- Increasing comfort and health
- Cutting down on operating, maintenance, and cooling expenses
- Significantly enhancing energy performance and saving money in the long run by choosing high-efficiency appliances and electronics.
The ultimate efficient home under the NBC and the BC Energy Step Code is a Net Zero home, or a Passive House.
In the US, the most widely used model building codes are the International Building Code (IBC) and the International Energy Conservation Code (IECC). Builders aiming to build the most energy efficient homes should be working towards the Department of Energy's (DoE) Zero Energy Ready Homes program.
Under any of these codes and programs, the goal is always to minimize home energy use and maximize the indoor air quality. The aim is to create and maintain occupant comfort, health, and safety.
Key Takeaways
- Incorporating principles such as the Envelope First approach, renewable energy sources, and energy-efficient equipment, right from the beginning of the design process significantly enhances a home’s energy efficiency and reduces utility bills.
- Effective air sealing, particularly in areas like attics and basements, is crucial for preventing air leaks and enhancing overall energy efficiency. This is the first principle for a home built to an energy efficient standard. After air tightness comes insulation.
- High-performance assemblies, as well as windows, doors, play essential roles in minimizing heat loss, maintaining indoor comfort, and achieving long-term energy cost savings. Optimize the efficient home envelope first and then add right-sized efficient HVAC systems.
1. Energy Efficient Home Design Principles
Maximizing a home’s energy efficiency and ensuring cost-effective implementation of energy efficiency steps starts with incorporating smart design principles from the outset. Some key design principles to consider include:
- Optimizing for solar gain in the winter and minimizing for it in the summer
- Designing the home to be air-tight and well-insulated
- Implementing smart home technology to monitor and control energy usage
- Using energy-efficient appliances and lighting
- Incorporating renewable energy sources on-site, such as solar panels
By incorporating these design principles, you can provide homeowners with significant improvements to their home’s energy efficiency, save energy, reduce their utility bills while maintaining a better level level of comfort. Homes with energy-efficient designs (with or without solar panels) can reduce the strain on power grids, leading to fewer power outages.
Harnessing Solar Energy
A home’s energy efficiency can be considerably enhanced by harnessing solar energy through passive solar design strategies. One key element is strategic home positioning, which involves orienting the house to capture maximum sunlight during winter and avoiding solar gain during summer. This method, known as solar tempering, optimizes the passive use of the sun’s heat for heating in winter. Shading keeps the house cooler in summer.
A passive solar home collects heat through south-facing windows, keeps the heat inside, and has a way to distribute it naturally or with fans. Some passive solar homes store heat in materials like concrete or brick, known as thermal mass.
Windows in a passive solar home should face within 30 degrees of true south and remain unshaded from 9 a.m. to 3 p.m. during the heating season. For effective shading, roof overhangs should be sized to block summer sun yet allow winter sun to penetrate south-facing windows. These strategies help reduce energy consumption and enhance the home’s energy efficiency.
Energy Modelling
During the design phase of an energy-efficient home, energy modeling software is an invaluable tool. It allows you to:
- Estimate a home’s energy use
- Ensure that the goal of net zero energy, or other energy performance target can be achieved while keeping costs down
- Take into account variables like construction materials, site characteristics, and climate conditions to estimate a home's energy performance.
Energy models can reduce energy use by up to 45% when used early in the design phase. Additionally, energy modeling helps ensure that designs comply with building codes and green building certification requirements.
2. The Envelope First Approach
When building a house you want to optimize energy efficiency through whole-house systems.
By focussing on the Envelope First approach, designers, builders, and renovators can cost effectively improve overall energy performance, such as enhancing insulation or optimizing building orientation. This approach also determines the cost-effectiveness of various energy-saving measures, projecting long-term savings.
There are three main points to the Envelope First Approach:
Improving energy efficiency and indoor comfort requires the sealing of the building envelope. Preventing unwanted air exchange contributes significantly to a home’s energy efficiency. Air sealing enhances the home's resistance to:
- water
- heat
- light
- noise transfer
Once you’ve determined what your airtightness goals are, then it’s time to consider the thermal envelope and insulation levels.
Mechanical ventilation is crucial to maintain good indoor air quality while ensuring the building remains airtight. By focusing on creating an airtight building envelope, homeowners can effectively reduce energy consumption and enhance their home’s overall performance.
Air Sealing Strategies
A home's energy efficiency is significantly enhanced by effective air sealing.
The goal is to have a continuous air barrier, which can be located on the interior or the exterior of the envelope. A range of materials and assemblies are available for new builds, making air tightness targets easier to meet.
In existing homes, there are more challenges to creating a continuous air barrier, but air sealing is still one of the most cost-effective ways to reduce energy consumption and increase occupant comfort.
Attics, in particular, are prime areas for air to escape, making them essential targets for air sealing. Using caulking and other sealants to minimize air flow significantly improves insulation performance. Sealing light fixtures and fans in unheated attics with airtight boxes helps prevent air leakage.
Likewise, sealing the home’s rim joist and foundation cracks with caulk or expanding foam helps prevent cold air from entering the basement.
In terms of building science, this ‘top and tail’ approach to air sealing helps to minimize the stack effect, controlling the primary driver of air pressure differences.
Control Moisture in Building Assemblies
In energy efficient construction, the goal is to control moisture and air from penetrating the building assembly. Keeping the wall, roof and other assemblies dry is a crucial part of building efficiency.
Keep water out, off, and away from the building envelope to prevent molds from growing. Mold can severely affect indoor air-quality (IAQ) and structural integrity in homes. Air sealing helps improve heating performance and provides better controls over the IAQ of the structure.
Advanced Framing Techniques
Reducing lumber use and waste while improving energy efficiency can be achieved by employing advanced framing techniques, also known as Optimum Value Engineering (OVE). These techniques involve using specific methods, such as spacing wall studs up to 24 inches on center and using two-stud corner framing with drywall clips or scrap lumber for drywall backing instead of studs.
Modular Design and Building Envelope
Designing on two-foot modules can make the best use of common sheet sizes and reduce waste and labor. Other methods include eliminating headers in non-load-bearing walls and using in-line framing to ensure that floor, wall, and roof framing members are vertically aligned, allowing loads to be transferred directly downward.
This helps to reduce thermal bridging to improve the performance of the envelope.
High-Performance Windows and Doors
Comfortable indoor temperatures are maintained and heat loss minimized with high-performance windows and doors. Windows, doors, and skylights can account for up to 35 percent of total house heat loss. They are always going to be the weakest link when it comes to heat loss,
Improving Comfort
Advanced insulation materials and energy-efficient windows help maintain comfortable indoor temperatures throughout the year. Some features that contribute to energy efficiency include:
- Inert gases like argon or krypton used between glazing layers to reduce heat transfer through the glass
- Insulated spacers between glazings to reduce edge heat loss and condensation problems
- Low-E coatings on windows that can reduce heat loss in the winter and heat gain in the summer by up to 50%
These features help to improve energy efficiency and reduce heating and cooling costs.
Properly installed high-performance windows can make homes more comfortable by reducing drafts and increasing the interior temperature of the window.
3. Efficient Ventilation Systems
In airtight homes, a healthy and comfortable indoor environment is maintained through efficient ventilation systems. High-performance homes require a continuous source of fresh filtered air for ventilation. In addition, effective moisture control is also critical due to their airtightness.
There are four basic mechanical whole-house ventilation systems:
- Exhaust
- Supply
- Balanced
- Energy recovery
Whole House Ventilation is Best
There are several types of ventilation systems available for homes:
- Exhaust ventilation systems: These are simple and inexpensive to install but can draw pollutants into the living space.
- Supply ventilation systems: These allow better control of the air that enters the house compared to exhaust systems.
- Balanced ventilation systems: These introduce and exhaust approximately equal quantities of fresh outside air and polluted inside air.
- Energy recovery ventilation systems: These are effective in climates with extreme winters or summers and high fuel costs. They recover about 70% to 80% of the energy in the exiting air and deliver it to the incoming air. However, these systems require more maintenance, including regular cleaning to prevent mold and bacteria buildup.
4. Choosing Efficient Heating and Cooling Systems
Meeting energy performance targets and reducing energy costs require the selection of efficient heating and cooling systems.
Options
Heat pumps, for instance, have a high Coefficient of Performance (COP), converting a unit of electricity into multiple units of heat, making them highly energy-efficient. Ductless mini-split heat pump systems allow temperature control for individual rooms, saving energy by heating or cooling only the spaces in use.
Boiler systems heat water, which circulates through radiators or baseboards, providing consistent and reliable warmth. Radiant floor heating provides even heat distribution from the ground up, offering high comfort and energy efficiency.
Forced air furnaces distribute heated air quickly via ducts, offering rapid warmth, though efficiency can vary. ENERGY STAR certified furnaces have a rating of 90% AFUE or greater, making them about 15% more efficient than the minimum federal efficiency standard.
Smart Controls
Optimizing energy use is made possible through the pivotal role of smart thermostats. These devices learn user preferences and create personalized schedules, initiating heating during off-peak hours to take advantage of lower-cost, clean energy.
This results in long-term savings on energy bills and enhanced overall cost-effectiveness.
Maximize the home’s energy performance through planning for energy efficiency, renewable energy systems to harness as much energy as possible before you start designing or remodeling.
5. Water Heating Solutions
Minimizing hot water use and saving on energy bills are achievable with efficient water heating technologies. Heat pump water heaters (HPWHs) use significantly less energy compared to conventional electric resistance or gas water heaters. HPWHs gather heat from the atmosphere and concentrate it in a water storage tank, leading to significant energy savings.
Although the initial cost of HPWHs is higher than conventional water heaters, this can be offset by long-term savings and available incentives.
Benefits of HPWHs:
- Lower energy consumption
- Reduced greenhouse gas emissions
- Longer lifespan compared to traditional water heaters
- Ability to operate in a wide range of climates
6. Energy Efficient Lighting
Reducing energy consumption and lowering maintenance costs can be effectively achieved through energy-efficient lighting. LED lighting uses up to 90% less energy than incandescent lighting, significantly reducing energy costs. ENERGY STAR certified light bulbs use two-thirds less energy than standard incandescent bulbs.
Advantages of LED Lights:
- They last 35 to 50 times longer than incandescent bulbs and about 2 to 5 times longer than fluorescent lighting, minimizing maintenance costs.
- They are more durable and do not break easily.
- Properly designed LED lights maintain consistent brightness and quality throughout their lifespan.
- The lifespan of LED lights can be at least 35,000 hours or up to 12 years based on 8 hours daily usage.
Selecting Energy Efficient Appliances
Minimizing home energy use and reducing environmental impact require the selection of energy-efficient appliances. By choosing energy star certified products, you can save money on electricity bills and help protect the environment by reducing harmful emissions. These products must meet strict energy efficiency criteria.
7. Renewable Energy Integration
Grid-tied solar photovoltaic (PV) panels are a cost-effective solution for powering zero energy homes. They are considered the most efficient form of renewable energy.
The panels are capable of meeting all the energy requirements of a home, including:
- Powering lighting
- Heating and cooling
- Operating appliances
- Providing hot water
While grid-tied solar panels are the most expensive component of a net zero home, strategies to reduce or mitigate the energy load of the house can save money. By reducing occupant loads as well as the heating and cooling loads, you can help your clients move closer to their goal.
The 'Envelope First' Approach Improves Energy Efficient Homes
Reducing reliance on mechanical systems is the primary drive of the 'Envelope First' approach to energy conservation. My personal preference is a 'stupid' house, not a smart one.
A stupid house has a great thermal envelope that means it is far more resilient and requires fewer controls and less monitoring to maintain it's integrity if there is power outage or a problem with the internet.
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One-Time Investment
There is literally a one-time investment in creating an energy efficient home. The design phase is the least expensive phase of any efficient home.
Where possible, choose low-carbon materials for the building envelope. Carbon mitigation is going to be a big deal - in fact, BC has already released a Carbon Step Code to help reduce greenhouse gas emissions associated with both the construction and operation of buildings.
Summary
Learning to build energy-efficient homes is not just about adopting a few green technologies; it’s about a holistic approach that integrates smart design principles, harnesses solar energy, employs energy modeling, pays attention to the details for air sealing, and uses efficient systems and appliances.
By following the strategies outlined, from sealing the building envelope to integrating renewable energy sources, you can help homeowners achieve significant savings, enhance comfort, and contribute to a more sustainable future.
Learn more about high performance and net zero energy in new construction.
Frequently Asked Questions
What are the benefits of a net-zero home?
The benefits of a net-zero, or near-net-zero home include significantly reducing utility bills and environmental impact by generating renewable energy on-site to offset energy they use over a year. Minimizing or eliminating energy costs for a home or building reduces the risks associated with fluctuating fuel and utility costs.
How does passive solar design enhance energy efficiency?
Passive solar design enhances energy efficiency by optimizing natural energy sources and reducing heating and cooling loads through strategies like site selection and window sizing and placement. Selective glazing moderates heating and cooling loads throughout the year, based on the orientation of the window.
What role does energy modeling software play in energy efficient home design?
Energy modeling software plays a crucial role in home design by estimating energy use, allowing designers to optimize variables for better energy performance and ensure compliance with building codes.
Why is sealing the building envelope important?
Sealing the building envelope is important because it controls air flow through the building envelope, reducing heat loss and increasing indoor comfort while providing resistance to water, pollutant, and noise transfer. This helps create a more sustainable and comfortable indoor environment.
What are the advantages of using heat pump water heaters?
Using a heat pump water heater can result in substantial energy savings and lower electricity bills related to water heating when compared to conventional water heaters, as they transfer heat instead of generating it, consuming less energy.
