Legan Construction & Remodeling
“We have trusted Legan Construction with several projects - from repairing some flooring that had been damaged, to installing sliding vinyl windows on our screen porch, to purchase & installation of garage cabinets.”
Best Insulation Contractors in Janesville, WI
10 contractors listed · 6 in Janesville · 1 open 24/7 · 5 open weekends · 8 rated 4.5+
Data verified October 20, 2026
Beneficial Insulation and Exteriors
“The integrity to our conversation was rare in today's world and hands down recommend them for your needs.”
Weather Seal Insulation and Roofing
“Crawl Space Spray Foam Insulation: The team was responsive and got the job done right.”
Janesville Insulation
“They were prompt and finished in a day, and at a reasonable price.”
Beneficial Insulation Solutions
“Cliff and his men have the expertise and equipment to troubleshoot and air seal and insulate hard to reach attic areas.”
Aurum Contracting
“His attention to detail from beginning to the end result was a great experience.”
The 10 contractors listed for Janesville, WI insulate attics, walls, crawl spaces and rim joists. Details under each one about materials, hours and the services advertised are copied from the company's own site; star ratings and comments come from public reviews.
Area overview: Janesville, WI
6 of the 10 contractors we list are based in Janesville; the other 4 serve Janesville from Beloit (10 mi) and Fort Atkinson (14 mi). The contractors on this page are rated from 4.2 to 5.0 across 353 reviews; 3 have 50 or more reviews and 8 are rated 4.5 or higher. When customers rate these contractors on specific qualities, they most often praise professionalism (97%), punctuality (85%) and quality (85%). The topics that come up most in reviews of the contractors on this page are "communication" and "price". 1 is open around the clock; 5 are open on Saturdays and 3 on Sundays. 1 shows a license on its website; 1 lists staff certifications (GAF) and 2 have a BBB rating of A or A+. Domain records put 3 websites of the contractors on this page at ten or more years old; the oldest dates from 2007. 2 offer emergency call-outs; 2 offer financing or payment plans; 4 give free estimates and 1 lists coupons or special offers. We count these figures across the contractors on this page; distances are straight-line, and hours and prices change, so confirm the details with the contractor before you book.
How many listings here have a website?
A website is on file for 7 of the 10 contractors here. Use it to see which materials they actually install, since a firm that only sprays foam will recommend foam. A contractor with no site is not automatically worse, but you will have to ask on the phone what the site would have told you.
Riedl and Son Exterior Specialists
“Cole got me all the information I needed and answered all the questions I had.”
Trademark Restoration Inc.
“Different color shingles and gutters totally changed the look of the house!”
A+ (Plus) Insulation Janesville
“The work has been done and they were so accurate but they cleaned up and left the space better than when they arrived.”
Swanson Spray Systems
Why these companies made our list
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