Residential heating & air conditioning contractor in Merrimack, NH
GSMS is proud to serve the residents of Merrimack, NH, with top-quality heating and air conditioning services. As a family-owned business with over three decades of experience, we are dedicated to providing reliable, efficient, and professional HVAC solutions tailored to your home’s specific needs.
GSMS is proud to be your Merrimack Lennox Premier Dealer!
Whether it's an emergency repair, a total replacement, or routine maintenance, we have you covered. Call 603-424-8258 today!
Air conditioner repair & replacement
- AC Repair: We handle cooling problems big and small with speed and attention to detail. Our technicians are trained to troubleshoot and fix refrigerant leaks, thermostat issues, electrical failures, compressor problems, and more.
- AC Replacement and New Installation: Time for a cooling upgrade? We offer high-quality systems from Lennox and other leading manufacturers to improve efficiency, enhance comfort, and reduce homeowners' carbon footprint.
Furnace repair & replacement
- Furnace Repair: Dealing with a broken furnace? GSMS technicians work efficiently to track down even the smallest of problems and repair them in no time. Common furnace issues we repair include pilot light problems, thermostat malfunctions, ignition system failures, and blower motor problems.
- Furnace Replacement and New Installation: Upgrading your furnace takes your home's winter warmth to the next level. Our energy-efficient systems provide consistent heating, reduced maintenance, and enhanced safety.
Boiler repair & replacement
- Boiler Repair: Common boiler problems with pressure, thermostats, pilot lights, and leaks, can be a homeowner's nightmare. GSMS technicians work quickly to repair your boiler and get your home warm again in no time.
- Boiler Replacement and New Installation: Whether you are considering switching to a boiler system or it's time to replace your existing system, GSMS is here to help you increase efficiency and reliability with advanced units.
Mini-split heat pumps
GSMS provides comprehensive services for mini-split heat pumps, including installation, maintenance, and repair. We specialize in Mitsubishi ductless units, known for their reliability and efficiency. Whether you’re looking to install a new system or need service for your existing mini-split heat pump, our technicians are here to ensure optimal performance and comfort in your home.
Ductwork cleaning & installation
- Duct Cleaning: Regular duct cleaning helps improve air quality, increase HVAC efficiency, extend system lifespan, and eliminate odors. We use an advanced Roto Brush system to reach every corner of the ductwork and keep your home clean and comfortable.
- Duct Installation: Proper ductwork installation is crucial for airflow, efficiency, comfort, and durability. Choosing GSMS to install your ductwork gives you peace of mind that your new air ducts are safe and secure.
Merrimack plumbing services
GSMS is proud to provide comprehensive plumbing services to homeowners in Merrimack, NH. Our experienced and professional team is dedicated to delivering reliable and efficient plumbing solutions tailored to your specific needs.
Quick plumbing repairs, complete installations, and preventative maintenance are what we do best. Call 603-424-8258 today!
Water heater plumbers
- Repair: Our skilled technicians can quickly diagnose and repair common water heater issues, including inconsistent temperature, leaks, and strange noises.
- Replacement: When it’s time to replace your old water heater, we offer professional installation of both traditional tank models and modern tankless systems.
- Maintenance: Regular maintenance is essential to keep your water heater running efficiently. Our comprehensive maintenance services include inspections, cleaning, and tune-ups.
- Tankless Water Heaters: Upgrade to a tankless water heater for endless hot water, improved energy efficiency, and space savings. We provide expert installation and maintenance for these advanced systems.
Kitchen plumber services
- Faucets: From repairing leaks to installing new faucets, we ensure your kitchen faucets are functioning perfectly.
- Sinks: We handle all sink-related services, including installation, repair, and replacement, to keep your kitchen fully operational.
- Garbage Disposals: Our team can install and repair garbage disposals, ensuring efficient waste management in your kitchen.
- Dishwashers: We provide installation and repair services for dishwashers, making sure they are properly connected and running smoothly.
- Water Lines: Whether you need new water lines installed or existing ones repaired, GSMS ensures a reliable water supply for your kitchen appliances.
Bathroom plumber services
- Toilets: From fixing leaks and unclogging blockages to installing new toilets, we provide comprehensive toilet services.
- Showers and Tubs: We offer repair, replacement, and installation services for showers and bathtubs to keep your bathroom comfortable and functional.
- Sinks and Vanity Plumbing: Our team can install and repair bathroom sinks and vanity plumbing, ensuring everything operates seamlessly.
- Pipe Repairs and Replacements: Whether it’s a minor leak or a major pipe replacement, GSMS provides expert pipe repair and replacement services to prevent water damage and maintain optimal plumbing performance.
Why choose GSMS in Merrimack?
- Proven Track Record: With a long-standing presence in Merrimack, NH, GSMS has earned the trust of countless homeowners. Our dedication to excellence and reliability has made us a preferred choice for HVAC and plumbing services in the community. We are proud of our reputation and continually strive to uphold the high standards that have set us apart.
- Local Expertise and Dedication: GSMS has been serving the Merrimack, NH community for over three decades, building a reputation for excellence and reliability. As a family-owned business, we are deeply committed to our local community and understand the unique needs of Merrimack homeowners. Our local expertise allows us to provide tailored solutions that keep your home comfortable and efficient year-round.
- Comprehensive Range of Services: From HVAC to plumbing, GSMS offers a full spectrum of services to meet all your home comfort needs. Our skilled technicians are trained in the latest technologies and techniques, ensuring top-quality service for every job. Whether you need a quick repair, a new installation, or regular maintenance, we have the expertise to get the job done right.
Become a GSMS Home Club member today
Join the GSMS Home Club and enjoy exclusive benefits designed to keep your home’s HVAC and plumbing systems in top condition. Membership perks include:
- Priority Service
- No Diagnostic Fees
- 10% Off Repairs
- Home ID and Smart Monitoring
- Monthly Credits Towards Major Purchases
- Regular Maintenance
- Labor Warranty Upgrades
Call today for great service in Merrimack.
Trust the experts at GSMS to provide reliable, efficient, and top-quality services tailored to your needs. Whether you need a quick repair, a new installation, or regular maintenance, our dedicated team is here to ensure your Merrimack home remains comfortable and functional year-round.
Call 603-424-8258 today or fill out our online contact form to book an appointment!
Recent Jobs and Reviews in Merrimack, NH
Customers say: The recent reviews exhibit a predominantly positive sentiment, with recurring themes of satisfaction, professionalism, and expertise. Customers express gratitude, recommend the company, and acknowledge the quality of the work performed. Positive reviews frequently mention friendly and knowledgeable technicians, timely responses, and efficient service. Negative reviews are minimal and do not represent a clear, recurring trend. Overall, the reviews suggest a positive experience with the company, with many customers expressing satisfaction with their HVAC and plumbing needs.
Our Local Reviews by City
- Amherst, NH (9)
- Atkinson, NH (2)
- Auburn, NH (1)
- Barrington, NH (21)
- Bedford, NH (27)
- Candia, NH (2)
- Chester, NH (2)
- Concord, NH (6)
- Deerfield, NH (1)
- Derry, NH (2)
- Dover, NH (1)
- Durham, NH (2)
- Epping, NH (1)
- Gilford, NH (1)
- Gilmanton, NH (1)
- Goffstown, NH (7)
- Greenland, NH (2)
- Hampstead, NH (2)
- Henniker, NH (3)
- Hillsborough, NH (1)
- Hollis, NH (13)
- Hooksett, NH (12)
- Hudson, NH (6)
- Lee, NH (1)
- Litchfield, NH (3)
- Londonderry, NH (12)
- Manchester, NH (49)
- Merrimack, NH (40)
- Milford, NH (7)
- Moultonborough, NH (1)
- Nashua, NH (41)
- New Boston, NH (3)
- Newbury, NH (1)
- Newmarket, NH (2)
- Northfield, NH (1)
- Northwood, NH (1)
- Pembroke, NH (1)
- Raymond, NH (1)
- Rochester, NH (2)
- Salem, NH (3)
- Sandown, NH (2)
- Stratham, NH (5)
- Tilton, NH (1)
- Weare, NH (5)
- Windham, NH (7)
- York, ME (1)
Job Locations and Reviews
Quick service call to replace thermostat. Done in about 15 minutes, explained the workings. Very satisfied Great service as usual
Install Honeywell T6 estate. Program automated. Remeber to pnly use auto in late spring and early fall.
Check water pressure 65 psi after pressure reducing valve.I would recommend replacing pressure reducing valve it's over 20 years old. Average life is 8 to 12 years.Will check in hammer arrestor valve also
I completed the gas furnace maintenance today. I checked all electrical connections and everything looked good. I pulled and cleaned the flame sensor. The client replaced her air filter recently. Checked incoming and outgoing gas pressures and everything was according to manufacturer specifications. Lastly, I ran the unit in high and low fire and performed a combustion analyzer test to check for CO, CO2 and oxygen levels and everything was running great. I talked to the client about adding a UV light and a leak breaker on her water heater. I will email her over the estimates for those.
Jack was polite and very neat.
Replace bathroom faucet.
I added one bag of gravel by generator where rodent dug a hole. The GSMS HomeClub heating visit was completed today. Your 2 stage Lennox furnace is in great condition. Please see the maintenance form for details.
We have been working with GSMS for 8 years. They provide the best service for installs and maintenance. The people are very professional, friendly and do great work. Today Qwentin was the tech doing the service maintenance. This young man came at the time scheduled, knew what he was doing and did excellent work. If you are in need for heating, air conditioning and plumbing work, this is the company for you!
Completed the gas furnace maintenance. I start off checking all the wiring connections and everything looked good. The air filter looks brand new so I didn’t replace it. I replaced the humidifier pad and turned on the humidifier for winter mode. I pulled and cleaned the flame sensor. I checked incoming and outgoing gas pressures and everything was according to manufacturer specifications. Lastly I ran the unit in low and high fire and performed a combustion analyzer test to check for CO, CO2 and oxygen levels and everything was running great.
I replaced the modulating gas valve today. I checked operation and everything was running perfect. I also completed the furnace maintenance today as well. The air filter that was in it looked brand new so I didn’t replace it. I replaced the humidifier pad. Cleaned the flame sensor. I checked all the wiring connections and everything looked good. I tested incoming and outgoing gas pressures and everything was according to manufacturer specifications. Lastly, I ran the unit in high and low fire and performed a combustion analyzer test. This test checks for CO, CO2 and oxygen levels and everything was running great. I noticed that there is corrosion on the plug going into the gas valve that wasn’t able to be cleaned off. I let the clients know and told them that I would send them over an estimate to replace the wiring harness.
Installation of a high-efficiency heating and cooling system to provide the home with reliable and comfortable air. The equipment and ductwork will be installed in the attic space. The gas-fired furnace and central air unit will be installed horizontally and will feature our "Ceiling Saver Kit." This kit includes a secondary drain pan and an overflow sensor designed to protect your ceilings from any potential water damage caused by condensation overflow. New ductwork will be installed with a central return in the hallway and dedicated supply ducts throughout the space to provide even airflow coverage. A dedicated supply duct will be installed to drop from the attic, through the first-floor coat closet, and into the basement office space, where it will connect to a new wall register to provide conditioned air. The new gas line will be routed from the proposed propane tank location up to the furnace in the attic. Furnace venting will penetrate through the roof. The A/C condensing unit
Jack did a great job. Provided a lot of good information. Thank you
No heat on oil boiler caused by bad main control board. Thst was replaced and normal operation was restored. Thank you for signing us for GSMS HomeClub. I completed the included annual maintenance on your boiler. Everything went great.
Client was noticing that their single zone mini split unit was overheating and also under heating. I checked both of the thermistors and both were in spec. I called into tech-support and left my name and number but got no response for over an hour and a half, so I let the client know that we will come back and figure out the issue that it’s having. I turned the remote to act like the thermostat as well. I wanted to see if anything changes.
Excellent service
I completed the gas furnace maintenance today. I started off with checking all the wiring connections and the capacitor, everything looked good. I pulled and cleaned the flame sensor. I replaced the air filter with a 20 x 25 x 5 air bear filter. I checked incoming and outgoing gas pressures and everything was according to manufacture specifications. Lastly, I ran the unit and performed a combustion analyzer test to check for CO, CO2 and oxygen levels and everything was running great!
Excellent Service
Install garbage disposal and humidifier shut off
Pm on oil boiler,snaked master bath drain,replaced cartilage on hallway bath faucet (cold water side) Repaired drain on kitchen sink
Excellent
Lennox gas furnace maintenance. Replace toilet fill valve. Fix humidifer. Install hole home sediment water filter. Gina from the office will call to schedule the garbage disposal and supply valve replacement. Thank you!
GSMS Homeclub heating visit. All heating systems were gone through. There were no repairs found today. The damper for garage zone seemed to have a loose wire at the zone panel. I cycled it a few times and it was opening and closing. I replaced the 16x25x3 filter for basement air handler. You're all set & thank you!
Bad condensation pump. Replaced
Completed the furnace maintenance today. Started off checking all electrical connections and the capacitor and everything looked good. I replaced the air filter that the client supplied. I pulled and cleaned the flame sensor. Flushed the condensate pump with cleaner. I checked incoming and outgoing gas pressures and everything was according to manufacture specifications. I performed a combustion analyzer test to check for CO, CO2 and oxygen levels and everything looked great. I replaced the humidifier pad and when I went to test the humidifier for operation, it was not working. I found that the solenoid valve had failed. We will get Mark on the schedule to come out here to figure out the water banging sound.
Gsms HomeClub furnace maintenance. Everything went great. I also replaced the upstairs thermostat.
Expansion tank small leak. I un-threaded it completely and reapplied Teflon tape and pipe dope. I tested for leaks and all is set. Covered under labor warranty. Thank you!
Replace Zone Damper.
Tighten expansion tank
Performed the furnace maintenance today. I started off with checking all the wiring connections and everything looked good. I replaced the 20 x 25 x 5 air bear filter and the humidifier pad. I pulled and cleaned the flame sensor. I checked the capacitors and those were both good. I checked the gas pressures and everything was within manufacturer specifications. Lastly, I ran the unit and performed a combustion analyzing test for CO, CO2 and oxygen levels and everything was running great.
Quentin was awesome he was very professional, respectful and extremely knowledgeable and competent. Great personality. and exhibited interpersonal and communication skills.
Completed the furnace maintenance. I replaced the humidifier pad and put it into winter mode. I cleaned the flame sensor. I checked all the wiring connections and everything looked good. I checked incoming and outgoing gas pressures and everything looked good. Lastly I ran the unit in low and high fire and I checked the CO, CO2 and oxygen levels and everything was according to manufacture specifications.
We replaced the pressure reducing valve. Completed a furnace maintenance. Replaced the humidifier pad and put it in winter mode. The clients air filter was clean so he wanted me to leave a new one with him that he could replace. Checked all the wiring connection everything looked good. I cleaned the flame sensor. I checked incoming and outgoing gas pressures and everything looked good. Lastly, I ran the unit and performed a combustion analyzing test. I checked for CO, CO2 and oxygen levels and everything looked great.
Today I completed a maintenance on your Goodman propane furnace. I also completed a maintenance on your Rinnai tankles water heater. Everything went well and there were no repairs found at this time. Thank you! Please see maintenance for for details of what was done today.
Never problem with GSMS! They have installed and serviced my furnace and AC for 27 years. Over the years Mark has gone out of his way to fix problems and now crew is continuing his great service! I have recommended them to many people.
Very good experience - good communication from Gina about scheduling. Techs (Jack and Qwentin) showed up on time and completed the job (new hot water heater and related cleanup) efficiently.
Qwentin is a valued team member of GSMS (Granite State Mechanical Services). He is friendly and knowledgeable
Qwentin was on time and provided excellent service as always
Excellent in all areas of service. Punctual, courteous, kept us well informed of service progress. Upon completion of the furnace installation Adam explained all features of the new system , and addressed questions . The above statement can be said of all GSMS employees as we have used them over the years for several different systems installation. Excellent in all areas.
Excellent service
Friendly and knowledgeable
Everything is working great!
GSMS helped us out after I discovered water surrounding the furnace. Qwentin quickly found the issue, explained what happened and what needed to be fixed. Great communication, excellent service, and he left the area cleaner than he found it. GSMS is always a pleasure to work with.
Five Stars
Couldn’t have asked for a better installation of dishwasher/toilets. Mark was very personable and professional. Arrived on time and finished on time. Excellent experience
Very professional in all respects.
I have been working with GSMS for close to 8 or 9 years now. Had them replace my entire HVAC system and on demand hot water heater installed. Today just had my annual service for my HVAC unit done. They really do great work and all their technicians are very skilled and knowledgeable. I highly recommend them for anybody for your HVAC and plumbing needs!
Great overall service, always has done a great job for me!
Mark and his entire team do a wonderful job. Show up on time and treat your home with respect. Recommend them without reservations.
Outstanding service
Granite State Mechanical Services has been serving our home for 30 years. They show up on time, complete the work and treat your home with respect. I recommend them to all our neighbors.
