Net-zero homes (for Calgary)

Why should we build net-zero homes?

To make better choices for energy efficiency and reduce pollution.

Even if this system doesn’t work in Calgary, many other countries could use this idea. In Alberta, we have our own oil, gas and, coal and we use our natural resources to generate all the required energy for our homes including heating our homes. Our province's income comes from these natural resources which are what shapes our economy. If Edmonton had done this, why should Calgary not do it? They are being tested and have been found working well. So far the results are good. If we also follow the same practice, it would be not a waste of money. But then again we have to keep in mind how many people in the oil industry would lose their jobs.

But must remember that if we in Alberta do not use these forms of energy they can be exported to those who need them very badly. We can help in keeping the environment in Alberta clean.

Here are some steps to follow so you can consider building a NetZero home:

Step 1: Design Your Home

You can start by selecting a place and determine the climate, determine if the area you have chosen is efficient or not, and map out your visual home in your mind so you can get an idea of what to consider when you are designing and building the home.

When you are designing your home, don’t forget to consider these other important things:

Site Selection: Make sure to have good shade-free solar access, little exposure to weather, close to the local transits and, shopping centers so that way you don’t wasn't the energy of your normal car/electric car.

Climate: you don’t want your home system to be damaged so make sure to look after and find solutions when you build a net-zero home in an area that has more exposure to bad weather.

Shape: Think about the shapes you are using for your house and also think about the shape of the land and how you can place the generators to get air or solar panels to get sunlight.

Size: Did you know that if you plan storage, functionality and traffic flow of the house then you can make a 1500 sq ft. house for a family of 4? All you have to do is carefully plan out how you are going to use your storage wisely.

Thermal Boundary: Decide and plan out what is inside and outside the conditioned space.

Ceilings: You can either use flat or cathedral ceilings in your house.Whenever the height of the ceiling changes, there will be a wall separating the room from an unheated space (most likely the attic). This wall can most likely be hard to air seal and insulate. The insulation level of that wall needs to be equal to other exterior walls and also would need to be buried b a rigid material to close off that area.

Building Orientation: Place the building in a way that you a take the greatest advantage of the seasonal sun so that way you get to power your solar panel and get light for your plants to grow. This also helps you get passive heating and cooling for massive solar energy production. The climate can also involve in escalating passive solar heat gain during cold climates or natural shading in warm climates.

Roof overhangs: Built Overhangs on all sides except the south side. Because in Most of Canada the sun will be on the south of the sky during winter months, fewer overhangs on the south sides and more overhangs on the north side.

R-Values: Confirm the R-values on the house plans for the walls, ceilings, floors and U-values for windows and doors. Make sure to find the right R-values and U-values according to your climate zone.

Thermal Bridging: Clearly state measures for avoiding thermal bridging plans. You will have to include advanced framing techniques for the wall, floor, and ceiling systems as well as exterior foam sheathing, staggered-stud and double-stud framing.

Enclosing Insulation: Make sure to specify that wall insulation is fully covered with rigid sheets of OSB, Thermo Ply, or materials that are alike. Never design walls that are difficult to properly cover the insulation. If you are going to draw double-stud walls, be sure to include details for covering the framing cavity with a plywood cap across the parallel top plates and plywood bucks inside the window and door openings.

Air Seal Goal: Make sure to specify the airtightness that you want to have achieved in your house plans. This expresses the air changes per hour at 50 pascals (ACH50). The threshold is needed to reach net-zero energy which should be at 2.0 or less.

Air Barrier Systems: Analyze the type of air barrier system that is to be used. Will it be airtight drywall approach or ZIP System SIGA membrane and tape or another air barrier system? List all the air sealing materials that you want to use in your house plan.

Blower Door Directed Air Sealing: The Blower door directed air sealing has to be conducted after your ceiling drywall and insulation has been installed, locate unexpected air leaks so you can effectively seal them.

Heating and Cooling Equipment: Locate all heating and cooling equipment along with their pipes, ducts, and refrigerant lines. Find the hot water system and its efficiency rating. Draw these on the house plans.

Ventilation: Draw mechanical ventilation equipment and ductwork on the house plans as well as locate equipment and ducts inside the conditioned envelope of the building where possible.

Water Heater: Find a water heater to use and the best location to place it. Electric resistance water heaters are supposed to be located inside conditioned spaces in heating-dominated climates and on the outside of the conditioned space in cooling-dominated climates. Heat pump water heaters should be out of conditioned spaces in areas that are about 1000 cubic feet of volume and supply water heat.

Solar Energy System: Determine the size of the photovoltaic system. Look for the adequate roof area and proper tilt and orientation to give sufficient energy to reach the zero-energy threshold. Make sure that chimneys, plumbing vents, and other roof protrusions are located outside of the roof area for the solar panels.

Appliances: Look for energy-efficient appliances and their ratings with the Energy Star Products website to help you determine if the products are good for Net Zero homes.

Engage the Team: Create a team including insulators, framers, plumbers, electricians, and solar contractors. The team should identify the most cost-effective energy efficiency requirements in the design and the most cost-effective way to implement these requirements. You should show them the design and ask them for feedback so you can improve your design.

Step 2: Use Energy Modeling

Energy modelling helps you choose which energy-saving features are most cost-effective and good for your net-zero home. The energy model software is really important to design tool that helps home builders find the most cost-effective materials needed to either build or furnish the home. When you are modelling, you should analyze the energy impact of each and every design choice that you have and compare the R-values in each design so you know what is better for your home. You can model as soon as the designer creates preparatory plans with doors, windows, dimensions, elevation, and the basic floor plan. After you include everything above, you can adjust all measures that you take in this project to be the most cost-effective and energy-efficient for your home. The decisions you will make during the energy modelling will be shown on the final plan and construction documents.

Any energy-saving upgrade that costs less per kWh would be considered as cost-effective and must be integrated into your final plan. Using energy modelling can help you determine the cost-effectiveness of energy-saving procedures.

Energy Saving Comparison Chart

Improvement                                                    Energy Savings in BTU

Wall from R30 to R40                                                        200 000

Floor from R38 to R44                                                      500 000

Windows from U-0.28 to U-0.22                                       700 000

Heat Pump HSPF from 9.5 to 10.5                                   300 000

ACH from 2.5 to 1.5                                                           700 000

Adding 1 kWh of PV panels                                                  4800

Adding one 180 Watt PV panel                                               796

Ceilings from R50 – R60                                                   300 000

 

Step 3: Super-Seal the Building Envelope

Did you know that air sealing a home is the most cost-effective ventilation cost reduction measure? It is a way to reduce heating and cooling energy requirements.

When a net-zero house is designed it is a must like in the 3 glass pane window where inert dry gas kept between the glasses to reduce any heat gain or heat loss.

Similarly, in the Building Envelope construction, the outer shell is kept insulated from the inner shell and each envelope must be properly sealed from any air leak. This prevents any energy loss from the house. All corners of the construction end and terminations must be properly sealed with insulating material available in the market which expands as form after injection. Properly sealing the air inside the two inner and outer envelope helps heat loss and produce much reduction in the heating requirement in the winter.

Step 4:  Super-Insulate the Building Envelope

Always use the best of insulation on the walls roof and the base of the house so that the heat transfer can be minimized. Many modern materials with very low conductivity are available to fill the space between the building envelope walls roof etc. The conductivity of different insulating materials has been discussed earlier.

Step 5: Heat Water Wisely

The first step is to try and minimize the need for hot water. By doing this the amount of heat required to heat the water can be reduced. When possible Solar water heating could be used. This will a free.  Placing a large water tank that can hold the houses hot water requirement is essential. It must be placed in the proper place in the house so it will not lose its heat and heat loss is used to heat the whole house.

Electrical resistance heating is the best way to heat the water from the Rooftop solar PV generated electricity which is stored in a rechargeable battery. Battery power to be used only in an emergency only. The otherwise large size of costly battery needs to be installed. Use of all power after sunshine hours must be minimized and only very essential lights with dimmable LED lamps must be used. A DC powered fan can also be used.

Use of a DC power wiring will be used as a conversion of rooftop solar PV DC power to be converted to 110V AC and converted to DC power in many electronic types of equipment in the house. This could be TVs laptop Computers iPhones Cell phones etc.

Step 6: Use Highly Insulated Windows and Doors

The use of 3 glass pane windows and doors to help terminations that are well-sealed with proper rubber gaskets to prevent any air leaks must be installed. The door leading to the outside can have a double door to prevent the inside heat loss. One opens one door that comes into a common area closes the outer door before he opens the door to enter the house.

The 3 pane glass windows with some inert gas or dry Nitrogen filled between are used.

Use of thick curtains is recommended which are movable so as open when required and to get sunlight and heat to enter the house and in the cold night, the thick cloth curtain will prevent any heat loss. The windows must be placed in such a way the best use of daylight is used in the house including any glass windows on the roof to bring natural light.

There must be provisions to close these windows with a thick movable curtain when dark or in winter to reduce heat losses.

Step 7: Choose Solar Tempering

There have been recent advances in building materials and techniques. This has pushed designers of cost-effective dero energy homes to reduce passive solar design in favour of “solar tempering.”The higher the cost of low U-value/high SHGC windows the more benefits of having fewer windows. By doing Solar tempering it allows you to use this cost-effective alternative which you can take advantage of gaining solar heat without increasing window area or cost. It works best with common living areas and most windows that face south. Optimal shading lets in warmth in winter and excludes heat in the summer. Solar tempering provides added light and warmth to the living areas and may reduce heating costs from 10% to 20% without added expense and risk of overheating in the summer.

Step 8: Use The Sun for Solar Tempering

A home that is energy-efficiency can never be “to tight”. It must provide automatic ventilation to all homes that have been air sealed below 4 Air Changes per Hour (ACH). This ventilation helps to control the water flow of vapour and maintains excellent air quality for the health of the homeowners. To reduce energy loss in zero energy homes, heat ventilated air can be captured without wasting energy by installing heat recovery ventilators (HRVs) or energy recovery ventilators (ERVs). These ventilators bring fresh air into homes and release stale air while retaining about 70% to 90% of the heat from the released air and returning it to the incoming fresh air. Also, HRVs and ERVs each help manage moisture in the air in many different ways.

Step 9: Select a Heating and Cooling System That is Energy-Efficient

Heating and cooling systems are highly-efficient and cost-effective are also essential to meeting the net-zero energy goal. One excellent choice is an air source from a ductless heat pump (also called a mini-split heat pump). These systems are highly efficient and don’t have defects of central, forced-air systems or the high costs of thermal heat pumps.

10. Install Energy Efficient Lighting

Minimizing energy use for lighting, while making the most of light for residents, is an important feature of zero energy homes. LED lights are perfect for these tasks. They are more energy-efficient than CFLs, last many years longer and, do not contain mercury. LED lights can also meet a variety of different lighting needs such as very bright white, light to soft, warm light. Selecting the perfect LED lights for the task, locating lights strategically in your home, and utilizing natural light is as effective as possible can drastically reduce a home’s energy use.

11. Selecting Energy Efficient Appliances and Electronics

In a common zero energy home, about 40% of the home’s energy is used for heating, cooling and, hot water. When we plug our appliances in, it may take up 60% of our home’s energy. By selecting energy-efficient appliances and managing our electronic plugs is very important. Many net-zero homes that were built to model zero energy standards have ended up at not meeting zero energy standards and requirements because of the undoubtful energy wasted by plugging in our electronics.

12. Use the Sun for Renewable Energy

Solar photovoltaic (PV) panels provide the most cost-effective for renewable energy for a zero energy home at the moment. They can power all energy needs of a home including lighting, appliances, heating systems, cooling systems and, hot water. Although, they are the most expensive part of a zero energy home and strategies for reducing those costs are important to consider.