How to Design Solar Ready Homes

Learn what goes into making a home solar-ready, what a solar rough-in is and the ideal home design for solar panels.

How to Design Solar Ready Homes

If you are builder or homeowner and want to add solar panels to your new home or building, making it solar-ready will save a lot of money when you are ready to install the system, whether that is 5 weeks or 5 years in the future.

Minor investments now often pay great dividends in the future.

What is a Solar-Ready Home?

A solar-ready home is one that has been designed and prepared for a solar power installation to occur in the future.

Building a solar powered home requires a few quick changes from standard construction practices such as completing a solar rough-in, optimizing the roof areas for solar energy generation and of course making the array look good.

Solar-Ready Benefits

Save Money

The steps required to make your home solar ready are very inexpensive when done during the planning and design stage of the home building process.

If you've had much experience with contracting services before, you'll know that after-thoughts can be expensive.

Improve the Look

Designing a house with solar panels gives the option of integrating the array into the building shape in a complementary way.

Uniform shapes and large arrays can be more pleasing to look at than a patchwork of solar panels.

Roughing in a home for solar will hide any exterior cabling by installing the lines behind walls with your other electrical wires.

This creates a much cleaner finished product.

If you can't make a large uniform face, we will still minimize exterior cabling and match the solar panels to the face shape as best as possible.

Home With Solar Panels Alberta
Home Solar Power Installation on Home Not Designed for Solar

Better Performance

Building a home for solar panels can greatly improve the output of your system. Minor adjustments to the tilt and azimuth of your home can yield tremendous solar energy gains.

Alterations to roof faces can also make a world of a difference.

Gables, dormers, and ridge lines will all impact the available area for solar

Solar Home Design
Solar Home Design - Uniform Face, Obstructions Facing North, Metal Shingles Integrated

Prepare for the Future

Maybe you don't want solar now, but you might in the future as technology improves and prices drop. Preparing in advance is a wise decision that can save you contracting related stress in the future.

Having a solar-ready home gives you the option of a simple installation whenever you want.

If done with adequate planning, the solar rough-in will also negate any outer wall penetrations that may need to occur otherwise, which is important not only for aesthetic but to minimize risks associated with holes in the envelope.

Even if you don't wan't to complete the project, selling a solar-ready home is an added feature that the next buyer may value.

How to Make a Home Solar-Ready

Below are a few solar ready guidelines and technical specifications to consider when designing a home for a solar.

  • Design roof areas for solar placement
  • Place mechanical obstructions (vents, plumbing stacks etc) away from solar area
  • Install conduit
  • Electrical panel size and space
  • Consider roofing and attic type

If you want to set up a solar system for a home, follow these guidelines.

Design the Roof for Solar

Large rectangular unobstructed areas are ideal for installing solar electric systems. Designing a home and roof for solar is key to maximizing the aesthetic.

Solar modules are rectangular which make better use of available space on similar shaped roof areas. It is possible to install panels on triangular faces, but there will be more unusable areas on the face.

Steeper tilts and southern exposures will produce the most energy throughout the year. More on this below.

Solar Panels Designed for Home
Home Design for Solar Panels - Vents Moved to North Side, Large Uniform Face.

Remove Obstructions

Vents, plumbing stacks, chimneys, satellites, skylights etc can negate the placement of solar panels in those areas or require additional costs to move the devices.

Neither is ideal.

Placing the obstructions away from the solar face will allow more room to place panels. Ideally, the devices can be placed on faces that won't have solar panels, but this is not always possible.

If obstructions have to be placed on the face, grouping them together and near the crest, eave or edge will maximize the available space for installing solar panels on a new home.

Solar Ready Home Guidelines
Guidelines for Designing a Home for Solar Panels

Install Conduit for Solar Panels

Conduits for solar power systems are simple to install and will provide the benefits detailed earlier. This is the primary work required for a solar rough-in. It doesn't seem like much, but this simple step will save hundreds or even thousands of dollars when it comes time to install solar panels for your home or business.

At least 1 x 1.5" conduit should be installed from the electrical room to the attic. The conduit should be metal, rigid PVC, liquid tight flex or metallic tubing and be in a straight line if possible.

Larger homes may need larger or more conduits. When in doubt, increase the size of the solar conduit. The material cost of this is minor.

If a conduit is stubbed in the attic, ensure that the top is above the insulation and has a pull string.

Installing an attic access hatch is required (hopefully that is obvious).

The solar rough-in process is very similar whether it is being done for a home or a business, each requiring conduit or cable from the electrical room to the solar panels' location.  The key difference between commercial and residential solar rough-ins is sizing the conduit/cable properly.  Since commercial solar installations tend to be larger than residential solar installations, a larger cable/conduit will be required.

Space Near Electrical Panel

Providing a small area near the electrical panel will provide more flexibility should the homeowner want to install a string inverter in the future.

An area roughly 2' x 3' is sufficient for routing cabling and installing devices effectively.

Additionally, it is best to increase the electrical panel busbar size relative to the main breaker rating.

Huh?

Your electrician will know what to do. The main service is protected by a main breaker, most often 100A. The panel itself has a rating (determined by the size and thickness of the metal plate at the bottom) and has a separate rating. It is best to make sure the busbar/panel rating is higher than the main breaker rating. This will allow one to install more solar panels on the home if needed.

For future planning, it may be safest to increase the service size as well from 100A to 150A or from 150A to 200A. This will come in handy if an electric vehicle is desired in the future.

Remeber, if you increase the service size to 150A or 200A, increase the panel size to 200A or 225A respectively.

Roof and Attic Considerations

What roof type is installed may impact how to make the home solar ready.

It is common practice to install a solar-specific junction box which sits on the roof, but is flashed/weatherproofed. Cables are routed through this junction box into the attic/home so no cables are visible from anywhere on the ground.

Asphalt shingles can easily be worked with at anytime in the future, but other roofs can be a touch trickier.

Standing seam, corrugated, and metal shingle roofs can often benefit from having a junction box installed prior to/during the roofing stage. It is possible to retrofit this in, but it will be easier and more cost effective during the initial construction.

Metal shingle roofs may require additional support from your solar company and roofing company to install the racking supports. Once again, this is best done during the initial construciton/roofing stage to ensure the roof is sealed and all warranties upheld.

If the home is to have a vaulted ceiling (no attic), then additional measures should be taken to make sure cables can be routed internally. Simply putting in a conduit will not suffice here. To rough in a home for solar with a vaulted ceiling, the roof-level junction box should be installed and the cables or conduit connected on the interior side.

Home Design with Solar Power System

Solar Ready Guidelines

Natural Resources Canada has produced a set of solar-ready technical guidelines. Use these specifications in conjunction with the tips we have laid out here and always contact us if you have any questions or concerns.

Ideal Solar Home

Planning for solar during the design stage of a build is the best time to do so.  In the end, you will have a far more optimized solar power system if you plan ahead.  

The ideal solar home will have a large (as large as possible) face with a southern exposure with little to no interference from vents, chimneys and other obstructions.  

Solar panels on West and East faces are also applicable, but will suffer an efficiency loss relative to their south-facing counterparts.  Solar panels facing due East or West, will produce at approximately 80% of the energy that the same solar panels would if they were facings south.  Other factors, such as tilt, play into the exact efficiency loss from the azimuth, but 80% is an accurate ballpark estimate.  

The ideal tilt for solar panels in Edmonton is 45 degrees to 53 degrees (latitude).  Designing your home as close to this tilt is ideal, but it is certainly not detrimental if it can't be done.  Most homes are built with a 4:12 pitch, or 18 degree tilt, which is still fine for solar energy generation. Steep tilts are great for energy production but may come with added installation costs due to working at difficult angles.

Snow will shed better on steeper tilts which is ideal for off-grid homes or net-zero homes.

Questions, comments or concerns? We would love to hear your thoughts on this.

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