What is MERV? How do you choose the right MERV rating for your home or facility, and is it important?
You buy air filters whether you own a home or manage a business. You do this because indoor air quality is essential, and every HVAC system requires you to change the filters regularly. Your air quality and circulation efficiency depend on clear, clean, unclogged air filters as part of the system.
If you go to the store or search for air filters online, you’ll need to know your unit’s filter size and your desired MERV rating. The filter size you get is based on your unit specs. But what is MERV? How do you choose the right MERV rating for your home or facility, and is it important?
Zachary was very friendly, efficient and knowledgable. He was able to service both units in 1 hour. I would recommend Thomas Hoffmann A/C for any future needs for me.
Response from the owner:Thank you, Michael! We're glad to hear that Zachary provided you with friendly and efficient service. We appreciate your recommendation and look forward to assisting you with any future needs.
Great service and went the extra mile for us . We would most definitely use them again
Response from the owner:Thank you, Andre, for your kind words and for recognizing our efforts; we can't wait to serve you again!
Thomas Hoffman air-conditioning and heating is so wonderful and professional! Nick Hoffman was the technician that diagnosed my malfunctioning air conditioning system and determined how to fix it. He was so incredibly professional and even invited me to watch while he worked, and kindly explaining to me all the details about the problem and how he is fixing it. I am now a client for life with this company because of how professional, knowledgeable, and a delight to work with they are! I want to add that they prioritized helping me on the same day that I called and even was a holiday (and 90 degree heat out!), so that is another outstanding Effort from this amazing company! Thank you so much.
Response from the owner:Thank you, Carrie, for your wonderful feedback! We're delighted to hear about your positive experience with Nick and our team. Your satisfaction is our priority, and we're glad we could assist you on the same day. Welcome to our family of clients!
They were able to come out quickly to help when our AC went down in the heat! They were prompt, kind, knowleadgable, explained everything easily in ways I could understand, fixed the issue, and made the experience so easy! I felt comfortable with the technican in and around our home working. Nick took the time to answer some questions about an unrlated issue while there. They will always be who we call for our heating and cooling needs!
Response from the owner:Thank you, Erin, for your wonderful feedback! We're glad to hear that our team, especially Nick, was able to assist you promptly and make the experience comfortable and easy. Your trust in us for your heating and cooling needs means a lot!
I highly recommend Thomas Hoffmann for anything involving HVAC. The person replacing my furnace, Britton Buehrig, was Professional and took pride in his work. The job was very cleanly done.
Response from the owner:Thank you, Ray, for your kind words and recommendation! We're glad to hear that you were provided with professional service and a clean installation. Your satisfaction means a lot to us.
Excellent service. AC went out on a hot summer day, hooked up with them through Angi, and within 2 hours they had arrived and fixed the problem. Can't ask for more than that
Response from the owner:Thank you for your kind words! We're glad we could help you quickly on that hot summer day. Your satisfaction means a lot to us!
Nick Hoffman was great. He came short notice to fix a leaky air handler did it quickly and efficiently and also took a look at the AC plan on using them again for our service of our HVAC
Response from the owner:Thank you, Jenny, for your kind words about Nick and for trusting us with your HVAC needs; we're glad to hear he was able to assist you efficiently!
Super company to deal with. Always professional, knowledgeable and friendly. Zachery was my technician and explained everything he did throughly and in a manner I could understand. Very nice guy.
Response from the owner:Thank you, Maggie, for your kind words! We're glad to hear that Zachary provided you with excellent service and clear explanations. We appreciate your support and look forward to helping you again!
My a/c was not working correctly and I knew it needed to be serviced. The person came and cleaned what needed to be cleaned and he did what he could for the output. He was very professional and nice. We will definitely call them for our future needs.
Response from the owner:Thank you for the positive feedback! We're glad to hear that you were pleased with our prompt and friendly service. We look forward to assisting you again in the future!
Great service
Response from the owner:Thank you so much for your kind words! We're grateful for your support and delighted to hear you had a great experience.
Nick arrived to repair our ac earlier than expected. He quickly diagnosed and made the necessary repairs. The cost was reasonable. We will definitely contact Thomas Hoffmann for hvac services in the future..
Response from the owner:Thank you, Michael! We're glad to hear Nick provided prompt and efficient service, and we appreciate your trust in Thomas Hoffmann for your future HVAC needs.
We have used Thomas Hoffman Air Conditioning and Heating for AC issues for the last two years. We have been so happy with the service we have received both times. This year, we just needed a little maintenance as our unit wasn’t working to its full potential. I called first thing in the morning and was able to get a same day appointment! Nick was so personable and knowledgeable, and he got us back up and running and no time. Thank you again for saving us from the summer heat!! We are so grateful for the amazing customer service you guys provide!!!
Response from the owner:Thank you so much, Teri, for your kind words and for trusting us with your AC needs over the past two years; we're glad Nick could help get your unit back to its best, and we truly appreciate your gratitude for our service!
I txt Thomas Hoffman air-conditioning and heating Sunday early evening about 6:30 and just left A detailed message of what was going on with my AC I received an automated reply, saying they would contact me soon. I heard from them the next Morning at 11 AM to confirm what was going on with my unit and said they would have a Tech out today still but would be the last call between 6 and 8pm. I expected to get an appointment 2 to 3 days later. We’re in the middle of about an 8 to 10 day Heat wave of Mid to upper 90s. So imagine my surprise when I received a call from Zachary at 3:20 telling me he was in Saint Charles and was on his way to my house to look at the unit. When I explained what was wrong on the phone, he was pretty confident. He knew what it was once he got here, pulled off the cover and sure enough it was the capacitor. Pull the old one off and install the new one turned it back on and boom I have cold air blowing. I would highly recommend Thomas Hoffman, AC and heating and if you can request a certain Tech Zachary is your guy he is great super Frndly got the job done quickly and even interacted with my dogs Who are super friendly
Response from the owner:Thank you, Vicki, for sharing your experience with us! We're glad to hear that Zachary was able to resolve your AC issue quickly and that he made a positive impression on both you and your dogs. We truly appreciate your recommendation and look forward to assisting you again!
We can’t say how happy we are with the quick and efficient service! We came home Friday evening after work on a 95 degree day (with a week of 90 degree weather ahead) and our A/C was totally out. We called this small business owner around 6pm and he was here by 7:25. He replaced our wires, had cool air running, gave us some helpful tips for the future, and was already out the door by 7:50. He was very polite, friendly, straightforward, and saved our evening/weekend!
Response from the owner:Thank you, Morgan, for your wonderful feedback! We're glad our team could provide quick and efficient service to keep you comfortable during the heat. Your satisfaction means a lot to us!
Giovanni was so great. Explained things so I understood. He is kind. I appreciated him cleaning up and being so nice. Thank you.
Response from the owner:Thank you, Peggy! We're so glad to hear Giovanni made your experience enjoyable and that his kindness stood out to you. Your appreciation means a lot to us!
Tom & Nick have taken care of all our HVAC needs for multiple properties for over a decade. Great team.
Response from the owner:Thank you, Kurt, for your kind words; we're grateful for your continued trust in our business for your HVAC needs over the years!
We recently moved into an older home and had an issue with the AC not working. We called and were offered a same-day appointment. Nick was fantastic—very knowledgeable and professional. He quickly diagnosed the issue with the air handler and got it fixed, and also installed a new thermostat for us. He was honest and straightforward with his recommendations and never pushed unnecessary products. Highly recommend!
Response from the owner:Thank you, Adriana, for your wonderful feedback! We're glad to hear Nick was able to help you with your AC issue and provide excellent service. Your recommendation means a lot to us!
Zach worked fast and answered all my questions with ease.
Response from the owner:Thank you, Stephanie! We're glad to hear that Zach provided you with quick and helpful answers.
Thomas Hoffman replaced my water heater. They were effective, efficient and pleasant people with whom to work.
Response from the owner:Thank you, David, for your kind words about Thomas and the team; we appreciate your feedback and are glad you had a positive experience with your water heater replacement.
Nick was a true expert in explaining our options for a new thermostat.
Response from the owner:Thank you, Robert, for your kind words about Nick's expertise; we're glad he could help you with your thermostat options!
Responsive! Came over, even after hours to help resolve a critical issue that was caused by a lightning strike causing a gas leak. Would highly recommend!!
Response from the owner:Thank you for your kind words! We're glad our team was able to assist you promptly, especially during such a critical situation. Your recommendation means a lot to us!
Having Tom come to our aid was a great experience and he offered followup assistance with the fancy technology part of the appliance if we need it. We will call him again if the need arises. Merry Christmas.
Response from the owner:Thank you, Marilyn! We're glad to hear that Nick was able to assist you and provide follow-up support. We appreciate your trust in us and wish you a Merry Christmas!
They got the job done, we're very quick and very kind!
Response from the owner:Thank you for your kind words! We appreciate your feedback and are glad we could assist you efficiently.
Great service. Responsive. Well trained technicians. Honest friendly and thorough. I highly recommend Tom Hoffmann and his team.
Response from the owner:Thank you for your kind words! We appreciate your recommendation and are delighted to hear about your positive experience with our team.
As always, the Hoffmann technician was polite, professional, and efficient. Pricing is reasonable and even more importantly, they are dependable. I will continue to use Thomas Hoffman A/C and Heating.
Response from the owner:Thank you, Mark, for your kind words about our technician and for your continued trust in Thomas Hoffman A/C and Heating; we truly appreciate your support!
These guys are pros.
Techs are friendly, listen and explain what they are doing.
Office staff is responsive.
Fast service....
Response from the owner:Thank you, Clark, for your kind words! We're glad to hear our techs and office staff made your experience a great one. Your feedback means a lot to us!
Excellent service. A/C went out on a weekend. Called them on Saturday morning, they were out within about 2 hours. The fix was easy enough, and he even had the part in the truck! I recommend this company for all of your HVAC needs
Response from the owner:Thank you, Elaine! We're glad to hear you received prompt service and that the fix was smooth. Your recommendation means a lot to us!
The service technicians are very courteous and communicate well with the customer. They let you know what, if any, problems are found, the options, and the cost of the repair(s). Quick and efficient.
Response from the owner:Thank you for recognizing our service technicians' courteous and effective communication, we appreciate your feedback!
These guys were great. Quick to return my call. Up front pricing. Great work on the installation. And the installers were nice and friendly. Highly recommend Thomas Hoffmann.
Response from the owner:Thank you, Steve! We truly appreciate your kind words and are glad to hear you had such a positive experience with our team and Thomas Hoffmann. Your recommendation means a lot to us!
Hoffmann came out the same day I called them because our AC was out. The technician, Ryan, was able to get the system running again, was polite and responded to my questions. We’re off to a good start!
Response from the owner:Thank you, John! We're glad to hear Ryan was able to help and that you’re off to a good start with your AC. We appreciate your feedback!
Thomas came over promptly I spoke with him about my concerns with my unit. Immediately got to work trouble shooting and resolved my issues. A+
Response from the owner:Thank you, James, for your kind words and for recognizing Thomas's promptness and dedication in resolving your concerns; we appreciate your feedback!
We have called Thomas Hoffmann many times and they are very prompt and very professional.
Response from the owner:Thank you, Vicki, for your kind words about Thomas Hoffmann's promptness and professionalism; we truly appreciate your feedback!
Super friendly, helpful, and quick to make the fix.
Response from the owner:Thank you, Jack! We're glad to hear you found our service friendly and efficient; your feedback means a lot to us!
Not a customer, but witnessed one of their technicians have an episode of road rage in Clayton. I would be concerned about letting them into my house/business.
We really trust Thomas Hoffman AC and Heating. Nick Hoffman has serviced our units several times now and he is professional, knowledgeable and very easy to work with. He comes on time, so we don’t have to schedule a long waiting period. We would highly recommend this company.
Response from the owner:Thank you, Greg, for your kind words and for trusting us with your AC and heating needs; we’re glad to hear that Nick has provided you with such great service.
We’ve been looking for a locally owned small HVAC dealer for a few years. And we found it with Thomas Hoffmann Air Conditioning & Heating. We love their service technicians. They come on time, they know what they are doing, they don’t upsell you on every appointment and they like working for Thomas Hoffmann. A happy employee makes for a happy customer.
Response from the owner:Thank you, Mary, for sharing your wonderful experience with us; we're glad to hear you appreciate our technicians and their commitment to great service!
I called on a Monday morning as air conditioning was blowing warm air. They were able to come to my house very early afternoon and fixed the problem. Would highly recommend and will use them again.
Response from the owner:Becky thank you so much for your great review. We appreciate your business and your kind words.
quick to arrive and fast service
Response from the owner:Thank you, Connie, for your kind words about our quick arrival and fast service; we appreciate your feedback!
Very good, pleased with service.
Response from the owner:Thank you! We're glad to hear you were pleased with our service and appreciate your kind words.
Excellent service from Nick!
Response from the owner:Thank you, Margaret! We appreciate your kind words and will make sure to pass along your praise to Nick for his excellent service.
What Is MERV?
MERV stands for Minimum Efficiency Reporting Values. This rating measures how well a filter stops and contains airborne particles between 0.3 and 10 microns large. This includes dust, pollen, mites, and mold spores.
MERV ratings range from 1-20. A lower MERV rating only stops large particles of dust and pollen. A higher MERV rating contains all particles down to a much smaller size and will improve your indoor air quality without making your energy costs rise significantly.
MERV Rating Chart
MERV Rating
- MERV 1 – 4
- MERV 5
- MERV 6
- MERV 7
Average Particle Size Efficiency in Microns
3.0-10.0 microns at 20% efficiency
3.0-10.0 less than or equal to 20%
3.0-10.0 less than or equal to 35%
3.0-10.0 less than or equal to 50%
1.0-3.0 less than or equal to 20%
3.0-10.0 less than or equal to 70%
1.0-3.0 less than or equal to 35%
3.0-10.0 less than or equal to 75%
1.0-3.0 less than or equal to 50%
3.0-10.0 less than or equal to 80%
0.30-1.0 less than or equal to 20%
1.0-3.0 less than or equal to 65%
3.0-10.0 less than or equal to 85%
0.30-1.0 less than or equal to 35%
1.0-3.0 less than or equal to 80%
3.0-10.0 less than or equal to 90%
0.30-1.0 less than or equal to 50%
1.0-3.0 less than or equal to 85%
3.0-10.0 less than or equal to 90%
0.30-1.0 less than or equal to 75%
1.0-3.0 less than or equal to 90%
3.0-10.0 less than or equal to 95%
0.30-1.0 less than or equal to 85%
1.0-3.0 less than or equal to 90%
3.0-10.0 less than or equal to 95%
0.30-1.0 less than or equal to 95%
1.0-3.0 less than or equal to 95%
3.0-10.0 less than or equal to 95%
The most efficient air filter is called a HEPA filter. HEPA stands for high-efficiency particulate air. This air filter can theoretically remove at least 99.97% dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns.
Contact Thomas Hoffmann Air Conditioning and Heating
Whether you’re a business manager or a homeowner, Thomas Hoffmann Air Conditioning and Heating can help you determine what type of filter is right for your needs. With more than 30 years of experience and a master technician and mechanical engineer as our owner, we can replace, repair, and provide maintenance for your business or home’s HVAC system.
24/7 Service Call Now
At Thomas Hoffmann Air Conditioning & Heating, we pride ourselves on being a locally owned and operated HVAC company. With more than 30 years of experience and a master technician and mechanical engineer as our owner, we can replace, repair, and maintain your business or home’s HVAC system.
