Is your home/business right for solar?

You’ve tried lots of websites. Solar PV sounds great but you can’t figure out if your home is suitable for solar, whether it would be affordable or not, or even how to “go solar”.

We can help.

Those of us in the industry tend to throw around technical jargon, and then act surprised when clients look confused. (For anyone we’ve inadvertently done this to: Sorry!) So here are a couple of quick ways to determine whether investing in solar will be right for you.

1. Find your home’s electrical consumption.

This will be on your electric bill. What you’re looking for is a number in kWh (kilowatt-hours). If you have online access to your NS Power account, it’ll look like this:

NSP-account-detail-online

NS Power account detail online

If you have paper bills, see #10 in this image:

nspower-account-paper-bill

NS Power account detail – paper

Useful: your electrical consumption probably changes throughout the year, depending on your heating or cooling needs. So if you have electric heat and choose a bill from summertime, your estimated consumption might be low compared to your actual needs.

For our example here, using 2010 Enerdata figures as per shrinkthatfootprint.com, our example home uses 11,879 kWh per year.

2. Use our Simple Solar Sizer (grid-tied only).

This tool is intended for educational purposes only. That is, it will provide you with a basic idea of what might be required to offset your home’s power use, but it is not intended to be 100% accurate–there are far too many variables to allow for an accurate calculation online. Play around with it a bit and you’ll see the effect your choices have on the overall system size.

Enter “11,879” in the annual kWh field, and see what number is calculated. You should see “10.80”. This means that our sample home requires a grid-tied solar system of at least 10.8kW in order to produce all its energy needs with solar.

[CP_CALCULATED_FIELDS id=”7″]

3. Calculate the space you’d need.

A typical residential solar panel (say around 250W) is about 39″ wide x 65″ tall, which is about 17.6 sq ft.

Let’s say our example home is a bungalow with a gable roof. A typical three-bedroom bungalow might have a roof of about 40′ x17′ or 680 sq ft on one slope. That gives us one slope of the roof facing south (ideally).

Gable-Roof-Type

There may be features such as stinkpipes, dormers and chimneys that reduce that surface area even further. There could be nearby structures like trees, neighbours, etc that shade portions of your roof, which further reduces your available surface area. 

Using our example above, we need a 10.8kW solar array. We’ll assume, for this example, that Nova Scotia Power and the Canadian Electrical Code will allow us to install this size of system.

Using 250W panels (industry standard, although 260W are also typical), that’s 10,800 watts / 250 watts = 43.2 panels. So we’d need to cram 44 solar panels onto the roof to get the full 10.8kW array.

44 solar panels x 17.6sq ft each = 774.4 square feet of physical space needed. Our wee bungalow with its 680 sq ft, even if it has a south-facing roof with absolutely no obstacles, just can’t do it.

You may not have the physical roof OR ground space available to dedicate to such a large installation. 

Some important notes:

  1. This calculation takes ONLY the solar panels themselves into account. A typical solar array also requires racking (to mount the panels), charge controllers, inverters, cables, lightning arrestors, and a number of other pieces to make it all work properly. Installation and permit costs are also additional.
  2. A ground-mounted array can be more expensive than a roof-mounted array, depending on the racking and ballast required.
  3. “Going off-grid” and being “net-zero” are not the same thing. Many people want to take their home and just unplug it from your electric utility. This would be going off-grid, except that it is usually not practical or cost-effective. (More on that in another post.)
  4. Net-zero is when you produce as much energy as your home requires throughout the year, effectively cancelling out your electric bill while maintaining your connection to the electric utility (in our case, NSPI).
  5. There are code rules and regulations that will affect the size of the renewable energy system you can tie into your utility, so even if you have the physical space to install 40+ solar modules (as well as relevant equipment) you might not have the electrical capacity to do so. An assessment by a qualified individual should provide you with that information.

For New Homes or Buildings

If you don’t already know your electrical usage–perhaps you’re building a new place and aren’t sure where to start–there are a number of “load calculators” online that will help. One of the best tools we’ve found so far is on Nova Scotia Power’s website, an online Energy Calculator. Please note that the results may not be your exact electrical loads, but they provide us and you with a good starting point.

Still with us? Here’s our conclusion.

Solar PV is a fantastic system, and can be a great investment for a grid-tied home or business–if it’s done properly. If you’ve gone through the tools we’ve posted here and think you might be a good candidate for solar, please contact us for a site assessment and we can help you determine your best options.

Off-grid solar is a different beast entirely. Please check out our Off-Grid Living page for more information.