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Windham, NH

Your Trusted Heating, AC & Plumbing Experts in Windham, NH

Since 1987, GSMS has been proud to offer top-notch HVAC services to residents of Windham, NH. With over three decades of experience, our family-owned business has built a reputation for excellence, reliability, and outstanding customer service. We provide a comprehensive range of HVAC services, including air conditioning repair, replacement, and maintenance, as well as heating services for furnaces and boilers. Our expert technicians are also skilled in installing and maintaining ductless mini-split systems, ensuring that your home stays comfortable year-round. At GSMS, we use only the highest quality products from leading manufacturers, guaranteeing efficient and long-lasting solutions for your HVAC needs. Whether you need a quick repair, a complete system installation, or regular maintenance, our team is dedicated to providing personalized service tailored to your specific requirements. Don’t let HVAC issues disrupt your comfort—call GSMS today at 603-424-8258 to schedule your HVAC service in Windham, NH, and experience the difference of working with trusted local professionals.

In addition to our heating and air conditioning services, we offer top-quality plumbing services to the residents of Windham, NH. With over three decades of experience, our family-owned business has established a reputation for trust, reliability, and exceptional customer care. Our comprehensive plumbing services include water heater repair, replacement, and maintenance for both tank and tankless models, ensuring your home has a consistent supply of hot water. We also specialize in kitchen plumbing, from faucet and sink installations to dishwasher and water line services. In the bathroom, our expert plumbers handle everything from toilet and shower repairs to vanity plumbing and pipe replacement. At GSMS, we use only the highest quality materials and the latest techniques to provide efficient and long-lasting solutions for your plumbing needs. Whether you require a quick repair, a complete installation, or regular maintenance, our team is committed to delivering personalized service tailored to your home’s unique requirements. Don’t let plumbing issues disrupt your daily routine—call GSMS today at 603-424-8258 to schedule your plumbing service in Windham, NH, and experience the peace of mind that comes with working with trusted local professionals.

Recent Jobs and Reviews in Windham, NH

Rated 5.0 out of 5 stars based on 10 customer reviews

Customers say: The overall sentiment across these reviews is overwhelmingly positive, reflecting high levels of customer satisfaction and appreciation. Customers consistently express enthusiasm about the quality of service they received, with recurring praise for professionalism, expertise, and efficiency. A dominant theme throughout is the technical skill and knowledge demonstrated by the service team, with many reviewers highlighting how thoroughly problems were diagnosed and resolved. The interpersonal qualities of the technicians emerge as another strong positive trend, with customers frequently describing them as friendly, personable, pleasant, and respectful. Communication stands out as a particularly valued aspect, with reviewers appreciating clear explanations, patience in answering questions, and being kept informed throughout the service process. Timeliness and punctuality are consistently mentioned as strengths, alongside respect for customers' property and maintaining clean, orderly work practices. Many customers express strong loyalty and trust in the company, with several indicating they are repeat customers or plan to continue using the service. The tone is enthusiastic and grateful, with multiple reviewers offering strong recommendations and expressing genuine happiness with the results. Overall, these reviews paint a picture of a service provider that excels in both technical competence and customer care, creating consistently positive experiences that foster long-term customer relationships.

Job Locations and Reviews

Qwentin G.
Qwentin G. Checked in
Found that the unit was low on refrigerant. I talked to the client and she wanted me to add refrigerant and UV dye. I added 1 lb of refrigerant. It brought the units temperature split to 22° which is very good. We will be back within 2 to 4 weeks to perform a leak search to see if we can locate where the unit is leaking from. The unit is from 2010 and the parts warranty ran out in 2016. Regarding the black stuff falling on the dresser I found that the blower wheel was getting dirty again.
Windham, NH 03087
Qwentin G.
Qwentin G. Checked in
Completed both AC maintenances. Everything went great! Please see the attached form.
Windham, NH 03087
Review
Quentin is a great ambassador for the Granite State brand! Great guy and trustworthy.
Michael Parker - Windham, NH 03087
Qwentin G.
Qwentin G. Checked in
Completed both mini split maintenances today. Everything went great! Please see the attached form.
Windham, NH 03087
Qwentin G.
Qwentin G. Checked in
Completed both of the AC maintenances. Everything looks great! Please see the attached form.
Windham, NH 03087
Repair cast iron railing along dock. Connect underground outside garage hose feed at hose down by basement doors. That frost free spigot needs to be replaced because it leaks.
Repair cast iron railing along dock. Connect underground outside garage hose feed at hose down by basement doors. That frost free spigot needs to be replaced because it leaks.
Jack D.
Jack D. Checked in
Repair cast iron railing along dock. Connect underground outside garage hose feed at hose down by basement doors. That frost free spigot needs to be replaced because it leaks.
Windham, NH 03087
Review
Glad to see the ole man still working!! LOL
Phil - Windham, NH 03087
Mark D.
Mark D. Checked in
Done not starting do to bad float switch.Replaced switch and cleaned pump housing
Windham, NH 03087
Review
Seems like a thorough inspection and update....great job Qwentin.
Phil - Windham, NH 03087
Completed the AC maintenance today. Started off with washing the outdoor condensers coil with coil cleaner and water. I checked all the electrical connections and the capacitor and everything was good. Inside I replaced the air filter with a client supplied filter. I cleaned the indoor coil with coil cleaner. I brushed and flushed the condensate trap with cleaner. I connected my gauges and ran the unit in cooling. The system was running great! I took some pictures of the dock railing and we will be in touch soon.
Completed the AC maintenance today. Started off with washing the outdoor condensers coil with coil cleaner and water. I checked all the electrical connections and the capacitor and everything was good. Inside I replaced the air filter with a client supplied filter. I cleaned the indoor coil with coil cleaner. I brushed and flushed the condensate trap with cleaner. I connected my gauges and ran the unit in cooling. The system was running great! I took some pictures of the dock railing and we will be in touch soon.
Qwentin G.
Qwentin G. Checked in
Completed the AC maintenance today. Started off with washing the outdoor condensers coil with coil cleaner and water. I checked all the electrical connections and the capacitor and everything was good. Inside I replaced the air filter with a client supplied filter. I cleaned the indoor coil with coil cleaner. I brushed and flushed the condensate trap with cleaner. I connected my gauges and ran the unit in cooling. The system was running great! I took some pictures of the dock railing and we will be in touch soon.
Windham, NH 03087
Windham, NH - Project Overview

During our recent service visit, Jack, noted significant scale buildup and active corrosion on several internal valves and fittings within your 11-year-old Rinnai tankless water heater. Given the age of the unit (originally installed during the home's construction) and the cost of rebuilding these internal components, we strongly recommend proactively replacing the unit. Upgrading now prevents a sudden failure and provides you with a brand-new system, full factory warranties, and renewed efficiency.

Scope of Work

1. Equipment Removal & Installation

Removal: Safely drain, disconnect, and remove the existing 11-year-old Rinnai tankless water heater.

Installation: Supply and mount a new, high-efficiency Rinnai Tankless Water Heater in the existing location.

Connections: Install new hot and cold water isolation valves (required for future maintenance and flushing) and reconnect to the existing gas and water lines.

2. Recirculation System

Integration: Your home is a
Adam P.
Adam P. Checked in
Project Overview During our recent service visit, Jack, noted significant scale buildup and active corrosion on several internal valves and fittings within your 11-year-old Rinnai tankless water heater. Given the age of the unit (originally installed during the home's construction) and the cost of rebuilding these internal components, we strongly recommend proactively replacing the unit. Upgrading now prevents a sudden failure and provides you with a brand-new system, full factory warranties, and renewed efficiency. Scope of Work 1. Equipment Removal & Installation Removal: Safely drain, disconnect, and remove the existing 11-year-old Rinnai tankless water heater. Installation: Supply and mount a new, high-efficiency Rinnai Tankless Water Heater in the existing location. Connections: Install new hot and cold water isolation valves (required for future maintenance and flushing) and reconnect to the existing gas and water lines. 2. Recirculation System Integration: Your home is a
Windham, NH 03087
Windham, NH - GSMS HomeClub Plumbing Visit.
Jack D.
Jack D. Checked in
GSMS HomeClub Plumbing Visit.
Windham, NH 03087
Jack D.
Jack D. Checked in
Could not find cause of error code. System running properly. I replaced dripping relief valve. Thank you!
Windham, NH 03087
Jack D.
Jack D. Checked in
Replaced hot water outlet valvebody & thermistor. Also replaced the inlet screen. Brought 3 air filters as well.
Windham, NH 03087
Windham, NH - Completed the plumbing inspection today. I checked all the fixtures and drains and everything looked great. I labeled a few emergency shut offs. I completed the rinnai water heater maintenance today as well. I started off with running cleaner through it for about 40 minutes. After I flushed 10 gallons of water out. I cleaned the water inlet screen. I cleaned the air filter screen as well. I checked incoming gas pressure and that was according to manufacturer specifications. I cleaned the electrode and flame sensors. Lastly I ran the hot water and it was working great.
Qwentin G.
Qwentin G. Checked in
Completed the plumbing inspection today. I checked all the fixtures and drains and everything looked great. I labeled a few emergency shut offs. I completed the rinnai water heater maintenance today as well. I started off with running cleaner through it for about 40 minutes. After I flushed 10 gallons of water out. I cleaned the water inlet screen. I cleaned the air filter screen as well. I checked incoming gas pressure and that was according to manufacturer specifications. I cleaned the electrode and flame sensors. Lastly I ran the hot water and it was working great.
Windham, NH 03087
Jack D.
Jack D. Checked in
Kitchen sink drain not draining. With the sample bit on my snake I pulled back grease and small food solids. I got the drain freed and treated it with lye. I reccomend putting lye down the drain once a month since that sink gets clogged often. It has a very long horizontal run in the basement. Thank you!
Windham, NH 03087
Windham, NH - Completed the plumbing walkthrough of the house. I checked all the fixtures and drains and the only thing that I noticed was the kitchen sink trap nut was a little bit loose so it's been dripping water. After tightening it, it wasn't dripping anymore. I completed the maintenance on the rinnai. I ran cleaner through it for about 40 minutes. I flushed it after with 10 gallons of water. I cleaned the supply water inlet screen. I vacuumed out the inside of the unit. I checked incoming gas pressure and that was according to manufacturer specifications. Everything went good today.
Qwentin G.
Qwentin G. Checked in
Completed the plumbing walkthrough of the house. I checked all the fixtures and drains and the only thing that I noticed was the kitchen sink trap nut was a little bit loose so it's been dripping water. After tightening it, it wasn't dripping anymore. I completed the maintenance on the rinnai. I ran cleaner through it for about 40 minutes. I flushed it after with 10 gallons of water. I cleaned the supply water inlet screen. I vacuumed out the inside of the unit. I checked incoming gas pressure and that was according to manufacturer specifications. Everything went good today.
Windham, NH 03087
I started off with completing the whole house plumbing inspection. All the fixtures and drains looked good and there we're no leaks. I cleaned out the filter for the air derator in the master bedroom. Next I completed the rinnai maintenance. I ran cleaner for about 40 minutes. After I flushed around 10 gallons of water through it. I cleaned the cold water inlet screen. I noticed on the hot water outlet there was a lot of rust and is starting to rot out the bottom of the hot water heater. I also noticed that the pressure relief valve has been dripping. I will send over an estimate to fix the leaking connection inside of the water heater and to replace the pressure relief valve. One thing I wanted to mention that I noticed with my plumbing inspection was that the bypass valve for the water treatment is opened when it is normally shut. I'm not sure if that was done on purpose by your water treatment company but I wanted to make aware.
I started off with completing the whole house plumbing inspection. All the fixtures and drains looked good and there we're no leaks. I cleaned out the filter for the air derator in the master bedroom. Next I completed the rinnai maintenance. I ran cleaner for about 40 minutes. After I flushed around 10 gallons of water through it. I cleaned the cold water inlet screen. I noticed on the hot water outlet there was a lot of rust and is starting to rot out the bottom of the hot water heater. I also noticed that the pressure relief valve has been dripping. I will send over an estimate to fix the leaking connection inside of the water heater and to replace the pressure relief valve. One thing I wanted to mention that I noticed with my plumbing inspection was that the bypass valve for the water treatment is opened when it is normally shut. I'm not sure if that was done on purpose by your water treatment company but I wanted to make aware.
Qwentin G.
Qwentin G. Checked in
I started off with completing the whole house plumbing inspection. All the fixtures and drains looked good and there we're no leaks. I cleaned out the filter for the air derator in the master bedroom. Next I completed the rinnai maintenance. I ran cleaner for about 40 minutes. After I flushed around 10 gallons of water through it. I cleaned the cold water inlet screen. I noticed on the hot water outlet there was a lot of rust and is starting to rot out the bottom of the hot water heater. I also noticed that the pressure relief valve has been dripping. I will send over an estimate to fix the leaking connection inside of the water heater and to replace the pressure relief valve. One thing I wanted to mention that I noticed with my plumbing inspection was that the bypass valve for the water treatment is opened when it is normally shut. I'm not sure if that was done on purpose by your water treatment company but I wanted to make aware.
Windham, NH 03087
Mark D.
Mark D. Checked in
Mike install data logger
Windham, NH 03087
Replaced rinnai control tower,3 way actuator and 3 way cartridge
Replaced rinnai control tower,3 way actuator and 3 way cartridge
Mark D.
Mark D. Checked in
Replaced rinnai control tower,3 way actuator and 3 way cartridge
Windham, NH 03087
Windham, NH - Had to order parts being sent over nite
Mark D.
Mark D. Checked in
Had to order parts being sent over nite
Windham, NH 03087
Completed the furnace maintenance for upstairs and basement furnaces. Downstairs I replaced the air filter and the humidifier pad that the client provides. I vacuumed out the inside of the unit as well. I checked all the wiring and everything looked good. I cleaned the flame sensor. I flushed the trap and condensate pump with cleaner. I checked incoming gas pressure and outgoing gas pressure and everything was inspect. Lastly, I checked CO, CO2 and oxygen levels and everything was within manufacture specifications. I didn’t replace the filter because it was very clean. I flushed the trap and condensate pump with cleaner. I cleaned the flame sensor. I checked gas pressures as well and everything looked good. Lastly, I ran the unit and did a combustion test as well and everything was within manufacturer specifications!
Completed the furnace maintenance for upstairs and basement furnaces. Downstairs I replaced the air filter and the humidifier pad that the client provides. I vacuumed out the inside of the unit as well. I checked all the wiring and everything looked good. I cleaned the flame sensor. I flushed the trap and condensate pump with cleaner. I checked incoming gas pressure and outgoing gas pressure and everything was inspect. Lastly, I checked CO, CO2 and oxygen levels and everything was within manufacture specifications. I didn’t replace the filter because it was very clean. I flushed the trap and condensate pump with cleaner. I cleaned the flame sensor. I checked gas pressures as well and everything looked good. Lastly, I ran the unit and did a combustion test as well and everything was within manufacturer specifications!
Qwentin G.
Qwentin G. Checked in
Completed the furnace maintenance for upstairs and basement furnaces. Downstairs I replaced the air filter and the humidifier pad that the client provides. I vacuumed out the inside of the unit as well. I checked all the wiring and everything looked good. I cleaned the flame sensor. I flushed the trap and condensate pump with cleaner. I checked incoming gas pressure and outgoing gas pressure and everything was inspect. Lastly, I checked CO, CO2 and oxygen levels and everything was within manufacture specifications. I didn’t replace the filter because it was very clean. I flushed the trap and condensate pump with cleaner. I cleaned the flame sensor. I checked gas pressures as well and everything looked good. Lastly, I ran the unit and did a combustion test as well and everything was within manufacturer specifications!
Windham, NH 03087
Jack D.
Jack D. Checked in
Replace UV bulb in water filtration system. Thank you!
Windham, NH 03087
Completed the furnace maintenance today. I replaced the 20 x 25 x 5 air bear filter. I also replaced the humidifier pad and turned the humidifier on. I checked all the wiring connections and everything looked good. I flushed the trap and condensate pump with cleaner. I checked incoming gas pressure and outgoing gas pressure and those were in spec. I ran the unit in high and low fire and performed a combustion analyzer test. I checked for CO, CO2 and oxygen levels and everything was with innmanufacture specifications.
Completed the furnace maintenance today. I replaced the 20 x 25 x 5 air bear filter. I also replaced the humidifier pad and turned the humidifier on. I checked all the wiring connections and everything looked good. I flushed the trap and condensate pump with cleaner. I checked incoming gas pressure and outgoing gas pressure and those were in spec. I ran the unit in high and low fire and performed a combustion analyzer test. I checked for CO, CO2 and oxygen levels and everything was with innmanufacture specifications.
Qwentin G.
Qwentin G. Checked in
Completed the furnace maintenance today. I replaced the 20 x 25 x 5 air bear filter. I also replaced the humidifier pad and turned the humidifier on. I checked all the wiring connections and everything looked good. I flushed the trap and condensate pump with cleaner. I checked incoming gas pressure and outgoing gas pressure and those were in spec. I ran the unit in high and low fire and performed a combustion analyzer test. I checked for CO, CO2 and oxygen levels and everything was with innmanufacture specifications.
Windham, NH 03087
Performed a maintenance on this propane furnace in the basement. Client supplies his own air filters. Checked the wiring and everything looks good. Ran unit on low and high fire. Checked the gas pressures and everything was in spec. Performed a combustion analyzing test to measure CO, CO2 and O2 and everything was in manufacture specs.
Performed a maintenance on this propane furnace in the basement. Client supplies his own air filters. Checked the wiring and everything looks good. Ran unit on low and high fire. Checked the gas pressures and everything was in spec. Performed a combustion analyzing test to measure CO, CO2 and O2 and everything was in manufacture specs.
Jack D.
Jack D. Checked in
Performed a maintenance on this propane furnace in the basement. Client supplies his own air filters. Checked the wiring and everything looks good. Ran unit on low and high fire. Checked the gas pressures and everything was in spec. Performed a combustion analyzing test to measure CO, CO2 and O2 and everything was in manufacture specs.
Windham, NH 03087
Review
Thank you for the prompt service!
Lori - Windham, NH 03087
Mark D.
Mark D. Checked in
Check uv lite looks like it's the bulb,went through rinnai with Mike Galivan,he is sending info to engineer,Couldn't find anything with lennox.It has high pressure code on August 12.Need appointment to go back when uv lite comes in
Windham, NH 03087
Jack D.
Jack D. Checked in
Perform deepclean on master bedroom mini split indoor unit.
Windham, NH 03087
Jack D.
Jack D. Checked in
Mini split maintenance today on both systems. Everything went great. The master bedroom indoor unit needs a deep clean performed. The blower wheel is clogged and that is the cause of poor cooling performance. We have sent an estimate to complete that service. Thank you!
Windham, NH 03087
Review
Fast and Efficient
Phil - Windham, NH 03087
Review
Mark is careful, knowledgable, efficient, and friendly Thanks!
Andy - Windham, NH 03087
Review
Thank you for the great service!!
Steven - Windham, NH 03087
Review
Fantastic. I couldn’t be more satisfied. I don’t have heat yet but I didn’t expect to. As long as he returns with the required parts in a reasonable length of time, I’ll be happy.
Edmund - Windham, NH 03087
Response from GSMS Air•Heating•Plumbing:

Thank you for the wonderful review and for taking the time to share your feedback.

Review
Excellent Service!
Lori - Windham, NH 03087
Review
Regarding the Faucet at my house ... would there be any kind of warranty on that unit - doesn't appear to be too long ago we put it in and now it became defective? Thanks - Phil
Montcalm - Windham, NH 03087
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