“Working with Horizon has been a flawless experience. David and team were totally professional throughout the process. David is friendly, smart and well trained in the field of residential energy. He offered a variety of options to improve the efficiency of our home and helped narrow the focus to remain within our budget. Their craftsmanship was top notch and the job was completed on time. David worked with us to get our Efficiency Maine rebate to help ease cost. Horizon took care of us every step of the way. Horizon gets my highest recommendation.”
— Yona Belfort, 2015 Customer in Cape Elizabeth

Happy Clients

"Always an extremely positive experience when working with Dave and his crew. From the get go Nate was informative about the the process and timeline of installing all new windows. He outlined options with advice that would best fit our home. When it came to completing the task the Horizon crew were always on time- polite and friendly something that is key to me when trusting them in your home. They were diligent in set up to minimize mess and always left the area as it was found. The final product looks great and has made our home even more efficient. This is the fourth time I have used Horizon and always had a great experience."

— Aaron Hagan, Portland, 2015-18


Luke dense-packing a kneel wall with cellulose insulation.

"Horizon just recently wrapped up our major Kitchen and Dining Room renovation that they had worked on from start to finish. David Milliken has assembled quite the impressive team and we are extremely pleased with the outcome. From the initial meeting, to the first day of demo, to the last day’s handshakes, the Horizon team was skilled, knowledgable, personable, polite, and very respectful. Nate Howe's crew always left the site swept, vacuumed with tools put away after every workday. We have never experienced this type of renovation of this magnitude before and they were always very approachable which was vital for making us feel comfortable during the job. Regardless the task, be it home efficiency resolutions or new construction, we would not hesitate a moment to recommend Horizon."

— Jeff swanson,Gray,2017

"In our efforts to make our house more comfortable and energy efficient, we have had the pleasure of working with Horizon. The success has been impressive. Horizon has been pleasant and easy to work with. Success has come from not just doing things, but from doing things right. No detail is too small to deserve attention and to have a positive impact. Thoughtful, no pressure, quality work. These are the people if you want a great job done well."

— Bill Newton, Portland, 2016


"These guys were unbelievable! Truly great to work with such a professional team. We had quite project and they over delivered on all aspects ( price, quality of work, time on-site, etc.). I would highly recommend to all. From the energy audit all the way thru to the end project; Horizon would be my choice again & again."

— Stewart Linsmith, Portland, 2016

"We initially had an energy audit completed by Horizon and were so pleased with the service. It was an extremely thorough audit of our old house and David provided us with an informative and easy to read summary of the results. The recommendations were clearly laid out with the price, the savings and indicating the priorities. We chose to have a new furnace/boiler installed by Horizon. It's incredibly efficient and makes us actually look forward to heating season in Maine as we'll be saving so much money! 

David and the rest of the crew at Horizon are professional, personable and reliable. We've been thrilled with them every step of the way and it's without any hesitation that we give a glowing review of this local, family owned company!"

— Liz Kalil, Portland, 2015

"Horizon recently installed air sealing and insulation into our 1955 Cape Cod style home. The results were immediately noticeable and were everything they had promised they would be.

Dave was very patient with all our questions and he was honest and open about what he thought would be the best approach to solving our issues (mostly ice dams and generally inefficiency). Rather than being pushy with up-sales, he gave us his thoughts on the best places to spend our money for maximum ROI and affect without breaking the bank. He was also a fountain of information – giving us many tips and ideas of things we could do to improve our home’s efficiency.

Nate and the crew performed the work in a professional and friendly manner. They were very clean and the workmanship was top-notch.

From an administrative perspective, their billing process was simple and easy and they even took care of all the tax-rebate paperwork for us!

If you’re looking to have home performance work done in Maine, call Dave!"

— Lance Davis, Cape Elizabeth, 2016