Merrimack, NH & Southern New Hampshire
Expert HVAC Service You Can Count On
Ondus Heating & Air Conditioning delivers professional heating and cooling solutions for homes and businesses across 18 Southern New Hampshire communities.
What We Do
HVAC Services For Your Home or Business
From routine maintenance to full system installations, Ondus Heating & Air Conditioning has the expertise to keep your home or business comfortable year-round.
AC Installation & Replacement
Professional central air conditioning installation and full system upgrades sized right for your home or business.
AC Repair
Fast, reliable air conditioner diagnostics and repair to restore your comfort when you need it most.
Heating Installation
Expert furnace and boiler installation with quality, energy-efficient equipment built to last New Hampshire winters.
Heating Repair
Prompt heating system repairs so your family stays warm all season long — no matter how cold it gets.
Preventive Maintenance
Scheduled tune-ups that maximize system efficiency, extend equipment life, and catch small problems before they become expensive ones.
Ductwork & Air Distribution
Design, installation, and repair of duct systems engineered for balanced airflow and maximum energy efficiency throughout your space.
Ductless Mini-Splits
Energy-efficient ductless systems — perfect for additions, sunrooms, older homes, or whole-home zoned comfort.
Commercial HVAC
Full-service commercial heating and cooling solutions for offices, retail spaces, restaurants, and light industrial facilities.
Why Ondus?
Southern NH’s Trusted HVAC Professionals
When your heating or cooling system needs attention, you deserve a company that shows up on time, communicates honestly, and gets the job done right the first time.
Locally Owned & Operated
We live and work right here in Southern New Hampshire. When you call us, you get a neighbor — not a call center.
Fully Licensed & Insured
Our technicians are licensed NH HVAC professionals, so every installation and repair is done safely and to code.
Honest, Upfront Pricing
No surprise fees. We provide clear estimates before any work begins so you always know what to expect.
Quality Equipment & Workmanship
We install trusted, energy-efficient brands and stand behind every job with our quality guarantee.
Residential & Commercial Experience
From single-family homes to commercial facilities, our team has the expertise to handle projects of any size.
Where We Work
Serving Southern New Hampshire
Based in Merrimack, we proudly serve homeowners and businesses across the following New Hampshire communities.
- Merrimack, NH
- Nashua, NH
- Manchester, NH
- Concord, NH
- Hudson, NH
- Pelham, NH
- Salem, NH
- Windham, NH
- Hollis, NH
- Litchfield, NH
- Londonderry, NH
- Derry, NH
- Bedford, NH
- Amherst, NH
- Auburn, NH
- Bow, NH
- Goffstown, NH
- Hooksett, NH
Not sure if we serve your area? Give us a call — we’re happy to help.
Ready to Schedule Service?
Contact Ondus Heating & Air Conditioning today for a free estimate or to book your next service appointment.
Get in Touch