Angie's LIST Guide to
HVAC Maintenance

You can help your home's heating and cooling systems work more efficiently and last longer by tending to regular maintenance. Some tasks, such as changing the furnace filter, can easily be done by the homeowner.


HVAC technician at work
Regular service calls by a qualified HVAC contractor are crucial to your system's long-term health. (Photo by Brandon Smith)

DIY Maintenance

What is your home's best defense against the cold of winter? It's an efficient and effective home heating system. But to get the highest level of performance from your gas, electric or fossil-fuel powered system, you'll need to give it some regular TLC by way of seasonal or regular maintenance. 

Most HVAC work should be done by a professional, but you can take some steps yourself to ensure the longest life for your system:

Change the filters regularly: This is one of the most important steps in system maintenance. Dirty filters mean your system has to work harder to move the air, causing poor performance and creating more wear and tear on the system. A clean filter also lowers your energy costs, since the system uses less power to do the same amount of work, and improves indoor air quality.

To maintain a unit's peak efficiency, Energy Star recommends changing the air filters every three months at a minimum. A fresh filter traps contaminants such as dander, pet hair and dust and helps the system run more efficiently, prolonging its life.

During high usage months in the winter or summer, check your air filters at least once a month and change them as needed.

Perform a visual inspection: Check your HVAC system regularly for warning signs that you need a professional to take a look. Catching problems early can save expensive repairs later on. Frozen coils, water leaks, and dirty evaporator or condenser coils could require an HVAC contractor's help. 

Watch the thermostat: Turning your thermostat even one or two degrees higher in the summer or a few degrees lower in the winter can save wear and tear on your system and make a big difference in energy usage. 

Beyond changing the air filter on a regular basis, one of the best ways to ensure your home's HVAC system is operating at peak efficiency is to have a qualified professional HVAC contractor tune up the system on a biannual basis. Energy Star recommends scheduling your system tune-up around the beginning of daylight savings time in the fall and its end in the spring. It's an easy way to remember to have your system serviced before the peak heating and cooling seasons. A standard tune-up is likely to cost you between $70 and $100, but it's money well spent. 

Video: Air Conditioning Maintenance Tips

Seasonal Checklist

Check out this Energy Star list of maintenance items a HVAC professional should inspect or service with each tune-up:

1. Check the thermostat settings
Installing a programmable thermostat is a great way to ensure your home's HVAC system cools and heats the home at the most efficient and opportune time. During a seasonal tune-up, an HVAC company should check the settings to make sure the system is heating or cooling as programmed.

2. Inspect electrical connections and test voltage on system components
Broken, loose or disconnected connections can mean your system isn't operating properly, efficiently or safely, which will also increase the likelihood of component failure.

3. Lubricate moving parts
Moving parts without the right amount of lubrication increase friction and decrease your system's overall efficiency. Without regular lubrication as needed, moving parts will also wear out more quickly.

4. Inspect the condensate drain
If the drain for condensation in your home's air conditioner, furnace or heat pump becomes obstructed, water damage, high humidity levels and possible mold or bacteria growth may result.

5. Check system start-up and shutdown controls for proper operation
The startup and shutdown cycles, usually based on the thermostat settings, should be checked to make sure the system is operating properly and safely.

6. Check, clean or replace the air filter
This should be a part of the regular service, but if you don't check or change your filters yourself, the HVAC contractor should be able to show you how to perform this essential task yourself.

Furnace Maintenance

1. Inspect the exhaust outlets
If your heating system isn't expelling its exhaust properly, a dangerous buildup of carbon monoxide or other gases may result. During a seasonal maintenance tune-up, the chimney flue or vent stack should be checked to ensure there's no corrosion, leaks or back drafting.

2. Check fuel lines and connections, burners and heat exchangers
Leaky or disconnected fuel lines or connections present both a safety risk as well as make a system less efficient overall. Burners with accumulations of soot and cracked heat exchangers also compromise a system's energy efficiency.

A/C Maintenance

1. Clean air conditioner coils, inside and out, before cooling season begins
Dirty coils make the A/C system run longer, decreasing efficiency and increasing cooling costs.

2. Check and refill the refrigerant charge if necessary
Not having the right amount of cooling refrigerant can lead to a damaged air compressor.

3. Clean and calibrate blower system components for optimal airflow
The A/C system produces cool air for the entire home by blowing warm air over the cooled coil. Ensuring that air is moving over the coil as efficiently as possible can mean increased durability and efficiency of the system.

HVAC Service Contracts

An HVAC service contract can be a very cost-effective way to make sure your system is properly maintained and to have someone on call when things go wrong. Depending on the amount of services offered, they cost between $150 and $500 per year, but they often include yearly inspections of both your furnace and A/C, discounts on major repairs, and preferred scheduling status when you have problems during the busy season. 


The coolant R22 has recently gone up from $45/lb to $65/lb. Our service rep told me that R22 is being phased out since R22 still depletes the ozone layer. New AC units will require R410 which is operated at significantly higher pressure that involves totally replacing the AC unit. He told me that a blue liquid, called UV dye, can be injected into the coolant system to check for leaks. The blue liquid can (at least in principle) aid in sealing the leaks. Does anyone know how effective this procedure is in stopping leaks?

There are few steps to find the leak
1- 1st with soapy solution purchased at an HVAC supplier I would spray the connection and look for bubbles.If i cant find any bubbles I would go to step 2
2-Put UV dye in the machine and return to the unit after 7 to 10 days or when the leak is noticeable.
3-Then after a couple of days to 10 days i would look for the leak with a UV light.

If the leak is very big, lasting only a few days, i would first recover the r22 then put 200 to 300 psi of nitrogen is the system and spray the soapy solution and look and listen for the leak. I have pictures on my web site, search mazgan brooklyn ny, and you see pictures of UV dye finding leaks.

I find that the that leak sealer lasts for a few months, not the whole summer season in new york.

I recently bought a 15 year old home, and so is the heat pump. Thanks for the article about the change in refrigerant. Now, I know why the bill was higher than the past. He recharged it with R-22, and had to make a special trip to get it. The service man was very competent, but he didn't explain much. Very quiet.

I'm, now very concerned about the life of this machine. I will have him come out, and inspect twice a year. In the meantime, would it be helpful to install suction, and discharge gauges around the compressor to watch the performance?

Thank you in advance for your advice.

We would like to get a quote on have our furnace serviced and cleaned. Need to get an early morning appointment.

What can I do to troubleshoot before having someone come to fix or give estimate.

When turning on a/c can hear the usual low humming of a motor (fan?) but it never kicks in. Air doesn't go on.

Hi, We live in Germantown, MD and would like to get a Maintenance Service for our HVAC/HeatPump system. Please email with details of different options. Thanks. Mohib.

Prices. Of replacing missing compressor or New system

How to detect if the solinoid valve is defective? and what is the syptoms of the A/C Compartments?

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