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Thermostat Installation, Replacement & Repair in Northern Virginia & Maryland
Upgrading to a smart thermostat, replacing an old one, or yours has stopped working? AVS Heating & Air Conditioning installs, replaces and repairs thermostats as part of your whole heating and cooling system. Our HVAC technicians wire the thermostat correctly for your furnace, heat pump or air conditioner and then test that it really runs your system.
Schedule thermostat service: call 703-457-9028 (Virginia) or 301-686-7129 (Maryland). Technicians are available 7 days a week.
Thermostat Services From Your HVAC Technicians
We handle thermostat work from start to finish: helping you choose and install a new thermostat, replacing an old one, and repairing one that has stopped working.
Thermostat Installation and Replacement
Most home thermostats run on 24-volt power from a transformer in the furnace or air handler. A new thermostat only works well if every wire goes to the right terminal, so we handle the whole job:
- Choosing the thermostat. We guide you on the options for your system: non-programmable, programmable, Wi-Fi or smart.
- Wiring. Heat (W), cooling (Y), fan (G) and power (R), plus the O/B reversing-valve terminal and the Aux/E terminals on heat pump systems.
- Power. Most Wi-Fi and smart thermostats need constant power from the C (common) wire. We check how your new thermostat will be powered: through the C wire or on batteries.
- Mounting. The base is fixed level on the wall. We prefer the same or a larger size so old paint marks stay covered.
- Testing. We run heating and cooling cycles and show you how the new thermostat works before we leave.
Types of Thermostats We Install
There are four common types of home thermostat. The right one depends on your system and how you want to control it.
- Non-programmable: simple manual control.
- Programmable: set a heating and cooling schedule for the week.
- Wi-Fi: change the temperature from your phone.
- Smart: learns your schedule and adjusts automatically.
Some older apartment buildings still use line-voltage thermostats, which work differently. Ask us if you’re not sure which type you have.
Thermostat Not Working? Quick Checks First
Before you call, try these safe checks. They solve a surprising number of “broken thermostat” calls.
- Blank screen: replace the batteries if it uses them, and check the breaker and the on/off switch near the furnace or indoor unit.
- Settings: make sure it’s set to Heat or Cool and the set point is above (heat) or below (cool) the room temperature.
- Schedule or hold: a program may be overriding your setting.
- Air filter: a clogged filter can trip safety switches, which looks like a thermostat problem.
Still not working? The cause is usually a loose or corroded wire, missing power, or a fault in the heating or cooling system itself. That’s a job for a technician.
Thermostat Repair
On a repair visit, the technician finds out whether the problem is the thermostat or the system behind it.
- The thermostat base and terminals are inspected for loose, damaged or corroded connections.
- Each color-coded wire is checked against the correct terminal.
- Power to the thermostat is checked, including the C wire or batteries.
- Heating and cooling cycles are tested after the repair.
If the thermostat is the problem, we repair or replace it. If the thermostat is fine and the system isn’t, we’ll tell you and diagnose the air conditioner, furnace or heat pump.
Why Homeowners Choose AVS for Thermostat Work
A thermostat controls your whole heating and cooling system, so it makes sense to have it installed by the people who service that system.
- HVAC technicians, not just installers. We know how the thermostat works with your furnace, heat pump and AC.
- Family owned since 1991 in Northern Virginia and Maryland
- 4.8★ on Google
- Licensed: VA HVAC #2705039269A · MD HVAC #520714137895 · MHIC #4192876
- All major brands, residential and commercial
- 24/7 emergency service: VA 703-457-9028 · MD 301-686-7129
Thermostat FAQ
Answers to the questions we hear most about thermostats.
How much does it cost to install a thermostat?
It depends on the thermostat you choose, how it will be powered and your system type. Call 703-457-9028 (VA) or 301-686-7129 (MD) for a price.
Do I need an electrician to install a new thermostat?
Most home thermostats run on low-voltage (24V) HVAC wiring, so an HVAC technician is the right person. We also check that your heating and cooling respond correctly afterwards.
My thermostat has no C wire. Can I still get a smart thermostat?
Often, yes. Some thermostats run on batteries, and the technician will check the right power option for the model you choose.
Will a smart thermostat work with my heat pump?
Most will, if the O/B and Aux/E terminals are wired and set up correctly. That setup is where many DIY installs go wrong.
Why is my thermostat on but the heat or AC isn’t running?
It can be the wiring, power, a safety switch or the HVAC system itself. A technician can test which one.
Which areas do you serve?
We serve 75+ cities across Northern Virginia and Maryland, including Fairfax, McLean, Arlington, Bethesda and Rockville.
Book Thermostat Installation or Repair
Call 703-457-9028 (Virginia) or 301-686-7129 (Maryland) to schedule thermostat installation, replacement or repair.
Areas We Serve — Since 1991
HVAC Services in Northern Virginia
We proudly serve customers throughout Northern Virginia, including Alexandria, Annandale, Arlington, Ashburn, Burke, Centreville, Chantilly, Clifton, Dunn Loring, Falls Church, Franconia, Gainesville, Great Falls, Herndon, Manassas, McLean, Oakton, Reston, Springfield, Sterling, Vienna, Woodbridge, and Fairfax.
HVAC Services in Maryland
We proudly serve customers throughout Maryland, including Rockville, Aspen Hill, Bethesda, Bowie, Burtonsville, Clarksburg, College Park, Damascus, Darnestown, Derwood, Fort Washington, Gaithersburg, Germantown, Montgomery County, Olney, Potomac, Silver Spring, and Wheaton.
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Testimonials Our Customer Stories
I first time used AVS Heating for a maintenance service and I was pleased with the service and signed up for their Service Contract for only $199. Yearly. Overall, great experience and highly recommended.
Clean, efficient, professional, that's how I describe AVS Heating. Our AC went out and Raul and Jose was able to install a new unit the next day. He and his crew worked in a freezing cold attic. The installation was perfect and the price beat the competition by a long shot. Courteous crew and owner. Highly recommended.
Jose was wonderful to work with! He was incredibly fast, professional, and helpful when my Oil Furnace stopped working. I was able to get a quote from him within a few minutes and he had my problem diagnosed and repaired very quickly. I would highly recommend him and plan to use him for any future AC or heating issues I may have.
This is the second time my fiancé and I have had AVS come to repair our appliances. The first time they took great care of our 8 year old LG fridge. This time our Mile dishwasher quit working. Jose came out and was extremely friendly and knowledgeable about the dishwasher. He diagnosed the problem very quickly and gave us an honest advice and replaced the water inlet valve. We will absolutely use them again when our appliances slowly start to go out on us one by one. Thanks guys!
A Neal, Came in as a second opinion from AVS company that was sent by my Home Warranty company. He listened to the issue and got to work. Tech was in and out within 30 minutes diagnosing the issue and taking care of the loud noise due to a idle pulley. Great Customer Service and Avs will be my recommendation to all of my friends!
For the past few weeks our 9 year old water heater had not been working properly. I called AVS and Anil came to troubleshoot the problem. He diagnosed the problem to be with the Temperature Sensor and ordered the part. When the part arrived Anil from AVS came promptly and changed the part. My family and I are thrilled to have lasting hot water again. A few weeks ago, our sump pump had stopped working. AVS sent a couple of men who replaced it with a new and more quiet one. The men were were polite, knowledgeable and professional, and did the work right the first time. I'm glad we chose this company.
Called and spoke to Wendy, she was very nice said she would order the part needed and would contact me when it came in. In less then a week the part came in and we scheduled an appointment. Irfan came out, he was very personable and replaced the part. He made sure our heater was up and running before leaving. We will definitely use Compare for any future needs.
Mr. A Neal and his team are great! We needed HVAC work done professionally and by code. They helped us fix a mess of mistakes that someone else previously made with the HVAC system. A huge relief to know the HVAC system in our home is in safe working order! Owner has a great knowledge of Hvac. Thank you very much!
This is the best company you can use for a new water heater installation. Danny is one of the few people that knows if you give a fair price and don't Price gouge people you'll make up for in word-of-mouth business. There's a reason he has 5 stars on Yelp and Google. This is the happiest I've ever been with any home service company, you must use AVS in Bethesda, Md. My in-laws have been using this company for over 13 years. I would strongly recommend to call this Company for repair or a new water heater installation.
Quick, fast, and curries. And I didn’t feel like I got gouged.
can't say anything bad! our washer took a poop on a sunday night.. we found AVS on yelp and called monday afternoon. The soonest they could come out was tuesday. He diagnosed the problem within minutes... a pump on my washer had failed. he didnt have the part in stock but he was able to get it and install it on Wednesday, He was professional and polite and did exactly what he said he was going to and when. I will def use them again! Thank you
Had AVS out after another company told us we needed to replace an entire air-conditioning heat pump system for $12,680. AVS fixed what was broken for 1063. Very knowledgeable and great service.
I called to have my dishwasher fixed and Aneal came over and was very nice and knowledgeable. He ended up fixing my dishwasher for half of the quoted price and I have a 90 day warranty. I couldn't be happier with the work and would recommend to anyone in need of appliance repair
Friends. That's what AVS means to my family. A company full of excellent characters, from the administration through to the technicians who go out of their way for us *every visit*. We have no hesitation calling these folks for our HVAC stuff - chances are high this will extend to the their Heating techs based on the fantastic service received to date.
I am very pleased with the service I received in the repair of my refrigerator. I called three other repair services and the wait was over a week! Jose, the technician was on time, answered all my questions, and completed repair needed at a reasonable rate. I will use them again if needed.
This was my first experience with AVS Appliance and Hvac. The tech was very courteous and friendly. He explained the work to be completed and what changes were made. Excellent work. I intend to use them in the future and would recommend this business to a friend. Thanks!!
Impossible to get a better service on my gas furnace on Sunday night. Within two hour my furnace was On again. Thanks to AVS.
Best company of Northern Virginia. AVS team is the best ever. We recommend this company.
Avs has come to my place and taking care of refrigeration and ac heating units. I am very satisfied with the quality of work and price.
We have been using AVS for several years and have been pleased with their friendly expert service.
The technician came out same day fix my no heat problem !! Excellent customer service, very professional!
They have installed unit at my home in 2004. I have a problem with my unit and they fix it on time
They were very nice and neat and knowledgeable.
Super
Very nice to work with reasonable rates great work
Coldest day of the year, they took care of business.
Good techs
Very good service
Excellent service. Anil has come out several times with short notice-professional and quick to resolve all issues. Has my trust for further services. And very pleasant
