A Comprehensive Guide to Energy-Efficient and Passive Homes
Energy-efficient homes have become essential for today’s homeowners. With utility costs climbing and environmental concerns growing, building or upgrading your home for efficiency is one of the most effective ways to cut energy bills and lower your environmental impact.
Still, achieving true efficiency can seem confusing. Terms like energy-efficient, passive, and net zero often get used interchangeably, but each one represents a different level of performance.
So what do these terms really mean? How can you design or upgrade your home to use less energy without sacrificing comfort? And if you already own a home, which improvements will make the biggest difference?
In this guide, we’ll answer those questions and walk you through the practical steps to achieving the kind of efficient, comfortable, and sustainable home you want.
What is a Passive House?
A passive home is designed to be highly energy-efficient. Rather than relying on constant heating or cooling, it uses smart building science to minimize energy needs altogether. This is achieved through five core principles: high insulation levels, airtight construction, thermal-bridge-free design, high-performance glazing, and heat-recovery ventilation.
What is an Energy-Efficient Home?
According to the U.S. Department of Energy, an efficient home design uses minimal energy, especially regarding appliances, home electronics, insulation, air sealing, lighting, space heating, cooling, water heating, windows, doors, and skylights.
An ultra-efficient home combines energy-efficient construction with renewable energy systems like solar panels or wind turbines. When those systems generate as much energy as the home consumes, the result is a net zero home, one that produces a $0 energy bill and the smallest possible environmental footprint.
Hear from founder Ben Zook about the elements of his house that make it ultra-energy-efficient and helped him achieve a net-zero home.
What is the Difference Between Energy Efficient, Passive, and Net Zero Homes?
The main difference comes down to design standards and performance goals:
- Energy-efficient homes focus on reducing overall energy use.
- Passive homes must meet a strict set of standards that dramatically reduce energy use.
- Net-zero homes combine these energy efficiency strategies with a renewable energy source like solar panels to produce as much power as they consume.
How to Apply the Passive House Principles in Your Home
Regardless of if you’re in the initial design stages of your new home or looking to improve your current home, these key principles can be applied to achieve a passive home:
1. SuperInsulation
Superinsulation involves having lots of high-performance insulation in the entire building envelope including the walls, roof, and floor to reduce the amount of heat transfer. This principle is especially important in homes designed prior to 1980 as there were no minimum R-value codes that time.
How To Apply this Principle in Your Home:
Signs You Need More Insulation;
- High winter or summer energy bills
- Uneven snowmelt patterns on the roof in winter
- AC runs most of the time in the summer
- Outside noise easily heard indoors
Where Heat is Lost:
- Attic, walls, floors, windows, doors
Add to Attic First:
- Biggest ROI
- Seal any air leaks and complete repairs before adding insulation
- Two options:
- Batt insulation: flexible, fits between joists, easy DIY, less effective in irregular spaces
- Blown-in insulation: : fiberglass or cellulose, fills small or odd spaces, cellulose is typically more efficient and less expensive; often faster with a pro and a blowing machine
Walls:
- Best retrofit option is blown-in insulation
- If walls are open during remodels, batts are fine
- Pros can apply foam for superior air sealing and thermal performance
Basement or Foundation:
- Nearly all basements lose heat as warm air moves toward cooler ground and outdoors
- Insulating basements reduces energy loss and heating costs
How Much Insulation is Enough:
- Use Energy Star climate zones for targets
- Approximate R-values per inch:
| Insulation Type | Amount (in inches) |
| Fiberglass Batts | 2.9 to 3.8 |
| High-Quality Batts | 3.7 to 4.3 |
| Blown-in Fiberglass | 2.2 to 2.7 |
| Blown-in Cellulose | 3.2 to 3.8 |
- More is not always cost-effective unless you catch a pricing break
Superinsulation offers the added benefits of more consistent indoor temperatures, quieter rooms, fewer drafts, less pollen, fewer insects, and lower chance of ice dams in snowy climates along with increasing the energy efficiency of your home.
2. Thermal-Bridge-Free Construction
A thermal bridge is a weak point in your home’s envelope that allow heat to pass through more easily. To achieve a passive home, you must identify and remove these points, so that your home is thermal-bridge-free and maintains consistent temperatures year-round.
How To Apply this Principle in Your Home:
- Address spots where heat bypasses insulation through framing and fasteners
- During remodels, add rigid foam or continuous exterior insulation to break bridges
3. Airtight Construction
Your home must have a meticulously sealed building envelope to prevent uncontrolled air leakage. This can be achieved in the following ways:
- Seal gaps before adding insulation around attic hatches, light fixtures, vents, plumbing and electrical penetrations, windows and doors
- Weatherstripping and caulk strengthen the air barrier so the insulation can do its job
4. High-Performance Glazing
This principle consists of adding specialized windows and doors that reduce energy loss and improve comfort. These windows and doors often feature multiple panes of glass (often triple glazed), insulated frame, low emissivity (low-e) coting, and air-tight insulation.
5. Heat-Recovery Ventilation
A heat-recovery ventilation system is a crucial component of a passive home. Not only does it reduce heat loss, but also improves the air quality inside a tightly sealed passive home. It brings in fresh air and exhausts out built-up pollutants, odors, CO2, and moisture. It also can retain heat or not depending on the time of year.
How To Make Your House Energy Efficient
If your goal is just to make your home energy efficient, you don’t have to adhere to the same strict standards as a passive home. There are some simple steps you can take to decrease your energy consumption which we’ll cover in more depth below.
Home Energy Saving Tips
Here are some general things you can do around your home to limit energy usage:
Cut Phantom Loads
Phantom loads are electronic devices and appliances that continue to use electricity even when they’re turned off. These hidden energy drains quietly increase your utility bill. You can reduce phantom loads and save energy in the following ways:
- Look for glowing LED lights to identify sources of phantom loads; common offenders include TVs, cable boxes, game consoles, audio gear, routers, office equipment, and chargers
- Turn off these devices when not in use
- Install power strips strategically so you can turn them off more easily with just one flick of the switch
- If these items aren’t connected to the power source, they can’t take energy
Prioritize with 80/20
The 80/20 rule states that 80% of the effects come from 20% of the causes. In this case, about 20% of your devices account for 80% of your home’s energy use. Identify which devices consume the most power and apply the tips above to reduce their impact.
Measure to Manage
Installing a kill-a-watt or similar meter allows you to see real-time usage and find replacement options. You can find a table from the Lawrence Berkeley National Laboratory on products that use the most standby power to better identify the biggest culprits and find replacements for them. While not all of your devices will be on this chart, it’s a great place to start.
Energy Daving Systems & Appliances
There are certain appliances and systems that may be a better alternative if you’re searching to reduce energy consumption. Here are a few examples that you may consider for your home:
- Ductless Mini Splits
- Zoned heating and cooling where needed: By strategically placing them throughout your home, you can turn these on only in the rooms needed and turn them off when they are no longer in use.
- Avoids duct leakage: Ducts can develop cracks and leaks over time. Going ductless prevents leakages that can eliminate air loss.
- High Seasonal Energy Efficiency Ratio (SEER) and Heating Seasonal Performance Factor (HSPF) ratings: These rating indicate how well a system heats or cools your home without wasting energy. A ductless mini split has SEER ratings above 20 and HSPF ratings above 10 while air conditioners have ratings between 13 and 21, meaning these systems are extremely energy-efficient.
- Smart Thermostats
- Heats and cools home only when necessary
- Schedule heating/cooling system to be on/off based on when you’re home or not
- Motion sensors that can detect when someone is home and turn off when no one has been detected for extended periods of time
- Phone location tracking allows your smart system to determine if you’re home or not and turn on/off accordingly
- Mobile app allows you to control your heating/cooling system from anywhere
- You can monitor energy usage from the app and learn more about how you can use less in the future
- ENERGY-STAR Appliances
- Products/appliances with this symbol signify that they are Energy-Star certified and have excellent energy saving performance and capabilities
- Use the Energy-Star product finder to find an energy saving appliance that meets your needs
Other Energy Savings Tips
If energy savings is an important goal, there are things you can do outside your home that can improve your energy. Here are some general energy savings tips worth implementing:
- Composting: Not only does this improve soil quality, but it can save you energy by recycling kitchen waste for you. Normally, you would use the garbage disposal and run power to process the waste or send it to a landfill which can pollute the Earth. Instead, composting puts this waste to good use.
- Recycling: While this doesn’t contribute to your home’s energy efficiency, it does help promote a cleaner environment and limit greenhouse gas emissions.
- Rainwater Harvesting: Water consumption can use up a significant amount of energy in the home. With a rainwater harvesting system, you can reuse rainwater for garden irrigation, watering livestock, flushing toilets, doing laundry, and other essential tasks and save energy that usually goes towards transporting water and running it through your household system.
Architectural Ways a Home Can Be Energy Efficient
Your home’s construction can play a huge role in its overall energy-efficiency. Many of the principles of passive homes can make your home more energy efficient, but in general, the following tips can help make your home energy efficient:
- Upgrade attic, wall, and basement insulation
- Seal the envelope before any major system changes
- Consider continuous exterior insulation during remodels
- Replace or tune up duct systems; consider ductless options to avoid duct losses
Energy Saving Tips for Winter
In the winter, it’s essential to lock in as much heat as possible to prevent overusing heating systems. Here’s some tips that can help:
- Open window coverings during sunny hours; close at night
- Check and replace weatherstripping
- Add attic or basement insulation if a room feels drafty
- Keep supply and return vents clear for proper airflow
Energy Saving Tips for Summer
In the summer, the opposite is true, it’s important to find ways to naturally cool the house to not overuse cooling systems. Here’s how you can save energy in summer:
- Close blinds and shades during peak heat
- Use ceiling fans to improve comfort and reduce AC run time
- Avoid running ovens and large appliances during the hottest times of the day
- Maintain HVAC and replace filters regularly
Make Your Home Energy-Efficient With Belmont Solar
Achieving an energy-efficient home is possible, whether you adhere to the rigorous standards to achieve an ultra-efficient or passive home, or simply limit your overall energy consumption to achieve a more energy-efficient one. Here at Belmont Solar, we don’t just install solar systems, but help provide people with the tools they need to limit their energy consumption and reduce their electricity bill.
If you’d like to learn more about how to have a more energy-efficient home, check out our solar resources. If you’re interested in having an ultra-efficient home that combines a solar system with energy-efficient practices, schedule a free consultation with us. Our team will walk through your energy savings goal and set up an energy audit and solar system installation that will help you achieve your goals.
If you’d like to see an example of what an ultra-efficient home could look like, check out our founder, Ben Zook’s home. Or stop by our net zero homes page to see what creating a home that results in a $0 energy bill looks like.