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FeaturedTaking CallsVerifiedSolar Companies in Markham, Ontario

Terawatt Solar

Featured in Markham Today 4.60 (44 reviews)(877) 648-3323

Based in Markham, Terawatt Solar has operated since 2016 and serves residential and commercial customers throughout Ontario. It specializes in rooftop solar with net-metered grid connections, using Longi Solar panels and SolarEdge Home Hub inverters.

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Business Highlights
  • It lists an active ECRA/ESA Electrical Contractor licence.
  • Installations are performed by an in-house Master Electrician and ESA-certified crew, with no subcontractors.
  • It offers an eight-year warranty on installation labour.
Service Area

Greater Toronto Area and all of Ontario.

Featured on ProsGrade. Terawatt Solar is one of 2 solar companies ProsGrade lists in Markham, Ontario.

Listing details

4 services listed, including Rooftop solar, Solar battery storage and Ground-mounted solar. Open weekdays, closed on weekends. Rated 4.6 from 44 reviews.

  • Verified listing details
  • Service information
  • Customer review signals
  • Photo gallery
  • Public contact information
  • Published local profile

How This Business Compares

How Terawatt Solar compares with the one other listing in its trade on ProsGrade in Markham, using public Google ratings and review counts.

  • Ranks in the top half of the 2 Markham solar companies on ProsGrade by Google rating and review volume.
  • Rated 4.6 on Google, well above the 2.5 average of other Markham solar companies on ProsGrade.
  • Has the most Google reviews (44) of the 2 Markham solar companies on ProsGrade.

Services Covered

4 services
  • Rooftop solarnet-metered grid connection
  • Solar battery storagebackup batteries paired with solar
  • Ground-mounted solarcustom-built racking
  • Commercial solar

Reviews

What customers say

Customers praise the installation workmanship. One customer says Terawatt handled permits, design and engineering, with the installation finished in a day. Another says Cosmin helped troubleshoot issues after installation and came on Boxing Day to try to fix one.

Customer Reviews

Brent Streeter

From my first contact with Terawatt to the completion of the installation, my experience was very positive. We had our panels installed during the beginning of the rebate program. Terawatt kept us informed of the status of our rebate request and did everything to ensure we met the criteria with both the Greener Homes initiative as well as Hydro One. The installation of excellent and the panels and converter have been flawless since being installed.
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Jerry Leung

Excellent Customer Service & Outstanding Solar Expertise I had an amazing experience with this company for both the installation and ongoing service of my solar panels. Their customer service is exceptional—very responsive, attentive, and truly dedicated to taking care of their customers. Every time I reached out, they replied quickly and made sure my concerns were fully addressed. The owner himself even followed up with a thoughtful message, which really shows how much they value their customers. It’s rare to find a company that combines professionalism, technical expertise, and genuine care, but they truly deliver on all fronts. Highly recommended to anyone considering solar panels. A dependable team you can trust!
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Wayne Hatherell

They installed my system in a very professional manor. I have been a building contractor for over fourty years and must say I appreciate the quality of workmanship. Cosmin was a pleasure to deal with!

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Frequently Asked Questions

What goes into a Terawatt Solar proposal?

It starts with a satellite roof analysis and a 12-month utility-bill audit. The proposal includes projected payback, a 25-year savings estimate and IRR based on actual energy consumption.

Does Terawatt help with the Home Renovation Savings Program?

It fills out pre-installation forms and assists with grid-capacity and permitting approvals. It also provides documentation for the post-installation audit.

Does Terawatt manage utility interconnection?

It manages local utility interconnection from application to meter swap.

Can customers monitor system production?

Customers receive a free monitoring app to track system energy production in real time.

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