What does the One Hour mean in your company name?

The 'One Hour' in our company name indicates our guarantee to be at your home in the predetermined window quoted when you set your appointment. If we do not show up within that window, your service call fee is waived. 1. Express Appointment: This is an appointment that is scheduled during a specified one-hour time slot. You are promised that a technician will arrive at your home within this one-hour time window. You will also receive a call when the technician is en route to your home. 2. Reserved Appointment: This is an appointment that is scheduled during a specified, two-hour time slot. You are promised that a technician will arrive at your home within this two-hour time window. You will also receive a call when the technician is en route to your home. 3. Standard Appointment: This is an appointment that is scheduled during a specified four-hour time slot. You are promised that a technician will arrive at your home within this four-hour time window. You will also receive a call when the technician is en route to your home. 4. Stand-By Appointment: This appointment is for overflow situations. This appointment will not have a specified time. You will receive a call when the technician is en route to your home. 5. Emergency Appointment: This appointment is for an unspecified time after normal business hours Monday – Saturday and all day on Sundays/Holidays. Calls are dispatched in the same order they are received. You will also receive a call when the technician is en route to your home.

Do you service emergencies after-hours?

Yes, we offer emergency services 24-hours a day, year-round.

How much will my service cost?

The size and complexity of your HVAC issue will determine the cost. Because our trained, licensed HVAC technicians must diagnose the issue before we are able to quote you an accurate cost, we require an appointment to be set to complete a diagnostic on your system. Once the diagnostic is complete, your One Hour(R) technician will walk you through all costs using our Straightforward Pricing(R) Guide so there are never any surprise fees.

How often should I service my HVAC system?

It's ideal to service your cooling system each spring and your heating system each fall to ensure you find small issues before they become big problems.

How often do I need to change my HVAC filter?

Your filter should be changed every one to three months, depending on conditions in your home and your region's climate.

Do you offer purchase financing?

We work built relationships with several lenders to ensure our customers are able to restore comfort in their homes. Ask your technician about your financing options.

What are the advantages of a smart thermostat?

Smart thermostats learn a household's patterns and adjust heating and cooling according to when a home is occupied, give homeowners the ability to control the thermostat remotely, and enable homeowners to reduce their energy use, saving you money.

HVAC means Heating, Ventilation, and Air Conditioning. HVAC systems refer to air conditioners, furnaces, and any unit that cools indoor spaces during the summer and warm them in the winter. In general, an HVAC system takes in air, heats or cools that air, and blows it into a room or any indoor space. While many homes have separate air conditioning and heating units, others have a heat pump that cools and heats the house. Not only do HVAC systems maintain desired temperatures, but they also improve indoor air quality and regulate humidity levels. But most importantly, these units provide comfort all year round.

What is a SEER2 Rating?

The SEER2 (seasonal energy efficiency ratio) is a measure of the efficiency of your heating and cooling system.The higher the SEER2 rating, the more efficiently a unit operates. The SEER2 rating of any given unit can range anywhere from 13 to 21.

Bringing Comfort Home

With Expert AC Services

One Hour Heating & Air Conditioning® of Northern Virginia

4.6

(538 reviews)

Heating & Air Conditioning

Services By One Hour

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HVAC Repair, Installation & Maintenance

Heating, AC & Furnace Repairs in Northern Virginia, VA

When homeowners want a reliable heating or air conditioning system that they don’t have to think about, they call One Hour Heating & Air Conditioning. We are the premier HVAC service provider in the United States for a simple reason: we actually care about your comfort.

At One Hour, we respect you, we respect your time, and, most importantly, we respect the trust that you put in us to keep your home comfortable. It’s why we back all of our work with a 100% customer satisfaction guarantee for two years, and it’s why we’re always on time—guaranteed.

We Have a Reputation

For Being Punctual, Friendly and Knowledgeable

4.6

(538 reviews)

Josette Hodges

07-13-2025

“Today I received service from Craig Moss of Modern Mechanical and he was AMAZING!!! Craig was professional, punctual, AND trustworthy. I say he’s trustworthy because as a first time homebuyer, I got three different quotes and Craig was the only person to teach me about my AC system, the home maintenance plan, and how to smartly save and invest in a newer system a year from now. AND he SAVED me a ton of money!💰…Thank you Craig!🙂🤗 One Hour is the only HVAC service that I will be using from now on!😎”

Michael Magrath

06-22-2025

“Just prior to listing our home for sale, our heat pump died. We contacted One Hour Heating and Air Conditioning, and they sent a technician that day. He was professional and knowledgeable. We could repair it or replace it. Given its age, we replaced it, and the installation was done in a few days. Tremendous service! Fast forward to our new home. We opted to replace both 21-year-old HVAC systems (upstairs and downstairs) and there was no doubt which company to call, One Hour Heating and Air Conditioning. The contracting process was simple and easy, and the price was very reasonable. The team of technicians, led by Ludwig, were on-time, professional, and did a great job and they thoroughly cleaned up when they finished, which was nice. After two transactions in 6 months, with both installations having gone smoothly, I can’t say enough and highly recommend them.”

David Long

01-30-2025

“Great chatting with Michael!”

Mimi B

01-21-2025

“Our service was completed by Michael. Our thermostat failed on 1/16, days before our scheduled service date of 1/20 so, we decided to wait rather than request additional service. Michael arrived on time, professional, courteous and his knowledge, observable. We asked that he address the non functioning thermostat prior to beginning the regular maintenance, given the expected drop in temperature. Michael quickly diagnosed and addressed the issue. We have received services from this company for over 10 years BUT, this experience with Michael was definitely the best. Thank you.”

John Andrews

01-18-2025

“Routine maintenance was performed by Michael Terry. He came in the advertised time frame, He was respectful to put covers on his shoes to prevent tracking dirt into the house; he was extremely friendly and informative. He executed his job quickly but efficiently, and gave valuable advice for future care. I commend him for his performance and for his abilities.”

Beverly Ballinger

11-18-2024

“Scott did an excellent job on my HVAC today he solved lots of air issues I was extremely pleased with his professional expertise. Highly recommend Modern Mechanics”

Joel Itskowitz

10-29-2024

“Love having one provider for HVAC, Electrical & Plumbing”

Gayle Blair

10-29-2024

“Carlos did and excellent job of checking and maintaining our ac system. He is an excellent technician”

10-13-2024

“Great company. We have been using them for several years. They are honest, respectful, punctual, & clean. All their techs are knowledgeable & respectful. Our guy is Carlos great guy. Efficient to the point and easy to talk too. If you have any HVAC you should definitely call One Hour!”

Charles Senor

10-11-2024

“Always easy to schedule, Jaime keeps it straight and to the point, won't use anyone else.”

HVAC Services You Can Count On

Our customers love what we do because we treat them like the neighbors they are to us. While we carry the One Hour name, were an independently owned and operated business with a personal investment in the local community. We back our work with a 100% satisfaction guarantee, provide StraightForward® pricing guides for your benefit, and will pay you back for being even one minute late to an appointment.

Here For You

When You Need Us Most!

Yellow One Hour Heating & Air Conditioning service van with company branding and slogan.

'Round the Clock Availability

No matter the hour, you can trust One Hour to be there to help you when you get hit with the unexpected.
100% Satisfaction Guarantee

We guarantee our materials, labor, and craftsmanship for up to two years from the date of your service.
StraightForward Pricing® Guide

Before we start any work, we discuss your available options so you know exactly what you are getting and how much it will cost. No hidden fees!
Always On Time…Or You Don’t Pay A Dime!®

We understand your time is valuable, so we promise to arrive at your home within the predetermined time window that you select, or your service call is free.