I have been using Mark for a few years now, maintaining our HVAC systems both at our old house and now at our new house. He is very responsive, honest, and a great trouble-shooter. He thinks like an engineer which I appreciate. Mark recently installed a new Heil HVAC system (2-stage gas furnace and 2-stage A/C) in our new home. The installation went very well and the new system works great! I would highly recommend Mark Olis for any HVAC needs.
RunBikeSwim
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June 16, 2026
Mark's reputation precedes him, and his work stood up to all the positive reviews he's received. Mark installed a two-stage variable speed system (A/C and furnace) for a much more reasonable price than the larger companies offered. He also repaired an auxillary heat pump vs trying to sell me a new one. The difference with Mark is he tells you what you need without the upselling headache. Larger providers tried to sell humidifiers, ionization add-ins, extended warranties, etc, whereas Mark asked questions to determine if I really needed them (I didn't). Mark shows up and does what he says he will do. It's a no-brainer to use Mark in the future as well as refer others, which I will do at every opportunity. He is hard-working, honest, and pleasant to speak with. Why can't all businesses run this way?
Mark Nelson
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June 03, 2026
Mark does a great job identifying the issue and explaining the problem before the repair. He definitely has the mindset of fixing it first. I definitely recommend him and have been using him for years.
Richard Niewiadomski
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April 06, 2026
Mark showed up within few hours of calling. Replaced a blower motor on furnace and total cost came in well below the quoted price I received from a larger HVAC company. If you want fast, quality service and great prices-Call Mark
Grant Lipps
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June 29, 2026
Mark was great! He was able to come fix my gas line leak very quickly. I definitely recommend for repairs.
Our Address
484 E Carmel Dr, Carmel, IN 46032, USA
Claim Listing: Mark Olis HVAC Repair & Service
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I have been using Mark for a few years now, maintaining our HVAC systems both at our old house and now at our new house. He is very responsive, honest, and a great trouble-shooter. He thinks like an engineer which I appreciate. Mark recently installed a new Heil HVAC system (2-stage gas furnace and 2-stage A/C) in our new home. The installation went very well and the new system works great! I would highly recommend Mark Olis for any HVAC needs.
Mark's reputation precedes him, and his work stood up to all the positive reviews he's received. Mark installed a two-stage variable speed system (A/C and furnace) for a much more reasonable price than the larger companies offered. He also repaired an auxillary heat pump vs trying to sell me a new one. The difference with Mark is he tells you what you need without the upselling headache. Larger providers tried to sell humidifiers, ionization add-ins, extended warranties, etc, whereas Mark asked questions to determine if I really needed them (I didn't). Mark shows up and does what he says he will do. It's a no-brainer to use Mark in the future as well as refer others, which I will do at every opportunity. He is hard-working, honest, and pleasant to speak with. Why can't all businesses run this way?
Mark does a great job identifying the issue and explaining the problem before the repair. He definitely has the mindset of fixing it first. I definitely recommend him and have been using him for years.
Mark showed up within few hours of calling. Replaced a blower motor on furnace and total cost came in well below the quoted price I received from a larger HVAC company. If you want fast, quality service and great prices-Call Mark
Mark was great! He was able to come fix my gas line leak very quickly. I definitely recommend for repairs.