# A9 Green / Total Green Energy Solution, LLC

**Trade:** Insulation & Weatherization · **Address:** 329 Massachusetts Ave, Lexington, MA 02420 · **Phone:** (781) 357-2454 · **Website:** https://www.a9green.com/ · **Languages:** English

**Rating: 3.7/5** (medium confidence) — from 24 reviews across 6 sources.
96% of sentiment-scored reviews read net-positive. Last 6 months: 0 reviews, 0 negative.

## The honest read

A9 Green is the firm builders call when a house has to prove it is efficient. Bijan Khosraviani's Lexington practice does HERS ratings, blower door and duct leakage testing, AeroBarrier air sealing and Passive House and LEED verification, and a good share of its written accounts are signed by construction companies rather than homeowners — Realnova, Sterling Solutions, Kenwood Builders.

What customers keep describing is money recovered. A homeowner writing in June 2023 said A9 was the HERS rater on their Mass Save renovation in 2020 and 2021 and that they got the maximum rebate and the maximum HEAT loan. A February 2023 customer said the team held their hand through the process and they received the maximum possible rebate; another that month, recalling a 2020 build, said the house came out more efficient and they claimed energy credits they would have struggled to find alone. In May 2023 a customer credited Bijan and his team with keeping them current on building technology so their rebates could be maximised.

The other half is the inspector. A December 2023 customer said communication was good throughout and the project went smoothly with the Needham building department. Sterling Solutions Corp, writing in December 2022 after seven years of projects together, said the team explains the best routes to a rebate while still meeting the required values — which is the whole difficulty of energy-code work. The one 4-star account, from February 2023, puts it plainly: several projects carried to a conclusion that satisfied both the building department and the client.

On the homeowner side, a March 2023 customer followed A9's recommendations and had insulation upgrades done, and in March 2025 a customer had blower door testing and praised the crew's knowledge. The Better Business Bureau puts the business at 17 years, grades it A+ and does not accredit it; the services listed there are home energy audits, insulation, weatherization, infrared diagnostics and air sealing. Its Houzz page and its own site list a stack of affiliations — RESNET, ENERGY STAR, Mass Save Partner, NESEA, the US Green Building Council, and PHIUS+ Passive House rating on the company's own account.

Two things to settle first. The Houzz profile lists general contracting, home additions and custom homes beside the energy work, while the company's own site describes a consulting and testing firm serving builders, architects and developers — so ask which of those A9 would actually be doing on your job. And the written accounts run from 2021 to March 2025 and lean heavily toward trade clients, so a homeowner should ask for a recent homeowner reference.

The right fit is a new build, a deep retrofit or a Mass Save project where the rating and the rebate are the point, and you want the paperwork and the inspector handled by someone who does it weekly.

**Strengths:**
- Maximum rebates — 2023 customers credit A9 with the full Mass Save rebate
- HEAT loan secured — 2020/21 renovation got the maximum rebate and loan
- Smooth with inspectors — 2023 project cleared the Needham building department
- Seven-year trade client — Sterling Solutions describes repeated rebate-and-code work
- Blower door testing — 2025 customer praised the knowledge and professionalism

**Concerns:**
- Mostly trade clients — several accounts are signed by construction companies
- Accounts end in 2025 — the newest customer review dates to March 2025

**Where sources disagree:**
- Houzz lists home remodeling, general contracting, home additions and custom homes for the company, while its own site describes an energy efficiency consulting and testing firm working for builders, architects and developers.

## Claims & citations

Every claim below is backed by real evidence rows — uncited claims are dropped in code before publication.

- A June 2023 customer said A9 Green was the HERS rater on their 2020/2021 Mass Save renovation and that they received the maximum rebate and the maximum HEAT loan _(confidence: high)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSUR4N3NUbE5nEAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgIDx7sTlNg%7C%7C?hl=en) — “5★ A9 Green was the HERS rater for our Mass Save Renovation project in 2020/2021. They were transparent and very responsive. We got the maxi…”
- Two February 2023 customers describe receiving the maximum possible rebate and, on a 2020 build, claiming energy credits they would have struggled to secure alone _(confidence: high)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSUNoMnRQTEN3EAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgICh2tPLCw%7C%7C?hl=en) — “5★ I used A9 for a recent home project. They held my hand through the process, were good to work with and we received the maximum possible r…”
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChdDSUhNMG9nS0VJQ0FnSUNoMnF6T3BBRRAB!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgICh2qzOpAE%7C%7C?hl=en) — “5★ I had a great experience with A9 when they helped me during my home construction in 2020.  I felt like my house was built more efficientl…”
- A December 2023 customer said communication was good throughout and the project went smoothly with the Needham building department _(confidence: medium)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChdDSUhNMG9nS0VJQ0FnSURWeWNfR29RRRAB!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgIDVyc_GoQE%7C%7C?hl=en) — “5★ Communicated throughout project well and went smooth with Needham building department.”
- Sterling Solutions Corp, writing in December 2022 after seven years of projects, said the team explains the best routes to a rebate while still meeting the required values _(confidence: high)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSUQtMVltVmRREAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgID-1YmVdQ%7C%7C?hl=en) — “5★ We have used A9 Green on numerous projects over the past 7 years. They are informative, courteous, punctual & explain the best ways to ge…”
- A March 2025 customer had blower door testing done and praised the work, knowledge and professionalism _(confidence: high)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChdDSUhNMG9nS0VJQ0FnTUNRaXBuN3pRRRAB!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgMCQipn7zQE%7C%7C?hl=en) — “5★ A9 Green did a great job with blower door testing. We were very pleased with their work, knowledge and professionalism.”
- A March 2023 homeowner followed A9 Green's recommendations and had insulation upgrades carried out _(confidence: medium)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSURoMzRuY0RREAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgIDh34ncDQ%7C%7C?hl=en) — “5★ Bijan and team were so wonderful to work with when we needed help figuring out how to make our home more energy efficient.  They were alw…”
- The Better Business Bureau lists the Lexington business at 17 years in business, grades it A+ and does not accredit it, with services covering home energy audits, insulation, weatherization, infrared diagnostics and air sealing _(confidence: high)_
  - [Better Business Bureau](https://www.bbb.org/us/ma/lexington/profile/energy-conservation-products/a9-greentotal-green-energy-solution-llc-0021-119886) — “Better Business Bureau grade: A+”
  - [Better Business Bureau](https://www.bbb.org/us/ma/lexington/profile/energy-conservation-products/a9-greentotal-green-energy-solution-llc-0021-119886) — “Services offered (Better Business Bureau): Home energy audits, Insulation installed, Weatherization, Infrared diagnostic, Air sealing”
  - [Better Business Bureau](https://www.bbb.org/us/ma/lexington/profile/energy-conservation-products/a9-greentotal-green-energy-solution-llc-0021-119886) — “BBB profile for A9 Green/Total Green Energy Solution, LLC at 329 Massachusetts Avenue, Lexington, MA: BBB rating A+ but not accredited, 17 y…”
- Houzz lists the company as a RESNET Rater member, ENERGY STAR certified, a Mass Save Partner and a member of NESEA, the US Green Building Council, ICC and BRAGB; the company's own site adds PHIUS+ Passive House rater and verifier and BPI Building Analyst _(confidence: medium)_
  - [Official Website](https://www.a9green.com) — “Stated certification/affiliation: PHIUS+ (Passive House) Rater and Verifier”
  - [Official Website](https://www.a9green.com) — “Stated certification/affiliation: BPI Building Analyst”
  - [Houzz](https://www.houzz.com/professionals/general-contractors/a9-green-total-green-energy-solution-llc-pfvwus-pf~1387541074) — “Listed certification: ENERGY STAR Certified”
  - [Houzz](https://www.houzz.com/professionals/general-contractors/a9-green-total-green-energy-solution-llc-pfvwus-pf~1387541074) — “Listed certification: RESNET Rater Member”
  - [Houzz](https://www.houzz.com/professionals/general-contractors/a9-green-total-green-energy-solution-llc-pfvwus-pf~1387541074) — “Listed certification: Mass Save Partner”
  - [Houzz](https://www.houzz.com/professionals/general-contractors/a9-green-total-green-energy-solution-llc-pfvwus-pf~1387541074) — “Listed certification: NESEA Member”
- The company's own site describes an energy efficiency consulting firm providing HERS ratings, AeroBarrier air sealing and Passive House and LEED certification support for homebuilders, architects and developers, founded by Bijan Khosraviani, PhD _(confidence: medium)_
  - [Official Website](https://www.a9green.com) — “A9 Green is an energy efficiency consulting firm based in Lexington, MA, providing HERS ratings, AeroBarrier air sealing, Passive House and …”
  - [Official Website](https://www.a9green.com) — “Ownership (self-reported): Principal and Founder: Bijan Khosraviani, PhD”
- Several of the written accounts are posted by construction companies rather than homeowners, including Realnova LLC, Sterling Solutions Corp and Kenwood Builders _(confidence: medium)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSUQtMVlmNmJBEAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgID-1Yf6bA%7C%7C?hl=en) — “5★ A9 Green is very knowledgeable and helpful team.  We very much value their expertise and highly recommend them!
Realnova LLC, Boston Deve…”
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSUQtMVltVmRREAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgID-1YmVdQ%7C%7C?hl=en) — “5★ We have used A9 Green on numerous projects over the past 7 years. They are informative, courteous, punctual & explain the best ways to ge…”
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSUNHaUotNkpnEAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgICGiJ-6Jg%7C%7C?hl=en) — “5★ Kenwood Builders has worked with A9 Green on multiple new construction projects over the last few years and have nothing but good experie…”
- The written customer accounts run from October 2021 to March 2025 _(confidence: medium)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChdDSUhNMG9nS0VJQ0FnTUNRaXBuN3pRRRAB!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgMCQipn7zQE%7C%7C?hl=en) — “5★ A9 Green did a great job with blower door testing. We were very pleased with their work, knowledge and professionalism.”
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSUNHaUotNkpnEAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgICGiJ-6Jg%7C%7C?hl=en) — “5★ Kenwood Builders has worked with A9 Green on multiple new construction projects over the last few years and have nothing but good experie…”
- 80 Google ratings averaging 5 stars over 24 written accounts from 2021 to 2025, one of them a 4-star _(confidence: high)_
  - [Google](https://www.google.com/maps/search/?api=1&query=A9%20Green%20%2F%20Total%20Green%20Energy%20Solution%2C%20LLC&query_place_id=ChIJr1NdKH6e44kRHkbDDbPPGaA) — “Google: 5★ from 80 ratings”
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSUNoN3NQX1NBEAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgICh7sP_SA%7C%7C?hl=en) — “4★ A9 Green has worked through several projects with me to a satisfactory conclusion for both the building department involved and the clien…”
- Specializes in Insulation & Weatherization _(confidence: high)_
  - [Google Reviews](https://www.google.com/maps/reviews/data=!4m8!14m7!1m6!2m5!1sChZDSUhNMG9nS0VJQ0FnSURoMzRuY0RREAE!2m1!1s0x0:0xa019cfb30dc3461e!3m1!1s2@1:CIHM0ogKEICAgIDh34ncDQ%7C%7C?hl=en) — “5★ Bijan and team were so wonderful to work with when we needed help figuring out how to make our home more energy efficient.  They were alw…”
  - [Official Website](https://www.a9green.com) — “A9 Green is an energy efficiency consulting firm based in Lexington, MA, providing HERS ratings, AeroBarrier air sealing, Passive House and …”
  - [Better Business Bureau](https://www.bbb.org/us/ma/lexington/profile/energy-conservation-products/a9-greentotal-green-energy-solution-llc-0021-119886) — “Services offered (Better Business Bureau): Home energy audits, Insulation installed, Weatherization, Infrared diagnostic, Air sealing”

## License

Status: **not_found** — verified against the official MA state registry, never self-reported.
Re-check at the official registry: https://contractorhub.mass.gov/s/hic-contractor-search

## Sources

- [Exa](https://linkedin.com/company/a9-green): 0 web mentions across the open web (each linked to its source)
- [Google](https://www.google.com/maps/search/?api=1&query=A9%20Green%20%2F%20Total%20Green%20Energy%20Solution%2C%20LLC&query_place_id=ChIJr1NdKH6e44kRHkbDDbPPGaA): 5.0★ from 80 ratings
- [Google Reviews](https://www.google.com/maps/search/?api=1&query=A9%20Green%20%2F%20Total%20Green%20Energy%20Solution%2C%20LLC&query_place_id=ChIJr1NdKH6e44kRHkbDDbPPGaA): Listed on this source
- [Official Website](https://www.a9green.com): Self-reported profile and service details
- [Houzz](https://www.houzz.com/professionals/general-contractors/a9-green-total-green-energy-solution-llc-pfvwus-pf~1387541074): Listed on this source
- [Better Business Bureau](https://www.bbb.org/us/ma/lexington/profile/energy-conservation-products/a9-greentotal-green-energy-solution-llc-0021-119886): Listed on this source

## Recent reviews

- **5/5 · Google Reviews · Nick Pieri · 2025-03-03**: A9 Green did a great job with blower door testing. We were very pleased with their work, knowledge and professionalism.
- **5/5 · Google Reviews · marc riel · 2024-08-26**: Please see updated
- **5/5 · Google Reviews · Micha Avramovich · 2024-08-09**: I have used A9 green on a multiple projects in Newton and Brookline Massachusetts. I am very happy with their service, their knowledge. The server is outstanding. They were there for me from the beginning of the project to the end and answer any question and guide me through the project from the beg…
- **5/5 · Google Reviews · Eileen Brito Rosa · 2024-08-08**: Great company to work with. Excellent communication and customer service.
- **5/5 · Google Reviews · Todd Sullivan · 2024-08-02**: These guys get the job done
- **5/5 · Google Reviews · T C · 2024-08-02**: The people at A9 Green are great professional service providers .
- **5/5 · Google Reviews · Alefe DeOliveira · 2023-12-13**: Communicated throughout project well and went smooth with Needham building department.
- **5/5 · Google Reviews · Jacquelyn Kozowyk · 2023-07-20**: The team was amazing. Great at communication, prompt, excellent service. They stayed on top of my project throughout and I’d recommend them to all!
- **5/5 · Google Reviews · Stephen Edwards · 2023-06-08**: A9 Green was the HERS rater for our Mass Save Renovation project in 2020/2021. They were transparent and very responsive. We got the maximum rebate AND the maximum HEAT Loan.
- **5/5 · Google Reviews · Adam Siegel · 2023-05-04**: Bijon and his team go above and beyond in making sure we are up to date on the latest building technology and are able to maximize our rebates!

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Data freshness: last scanned 2026-09-09T20:45:18.760Z.
Cite as: A9 Green / Total Green Energy Solution, LLC — Tavlee (https://tavlee.com/contractor/a9-green-total-green-energy-solution-llc-lexington)
Source: https://tavlee.com/contractor/a9-green-total-green-energy-solution-llc-lexington