Business ProfileHVAC Companies in Peoria, Illinois

Thermal Services, Inc. (TSI)

Listed in Peoria 4.90 (50 reviews)(309) 699-3333

Thermal Services, Inc. (TSI)

Thermal Services, Inc. (TSI) provides residential and commercial HVAC service in Peoria and Central Illinois. It has served the region since 2004.

Last Updated October 2, 2026.

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Business Highlights

Thermal Services is locally owned and operated.
Its technicians are union-trained, certified and licensed.
Thermal Services is a registered Program Ally with the Ameren Illinois Energy Efficiency Program.

Service Area

Residential: Bartonville, Brimfield, Canton, Carlock, Chillicothe, Danvers, Delevan, Dunlap, East Peoria, Edelstein, Edwards, El Paso, Eureka, Germantown Hills, Hopedale, Mackinaw, Mapleton, Metamora, Morton, Mossville, Pekin, Peoria, Peoria Heights, Roanoke, Tremont and Washington. Commercial: Addison, Alton, Aurora, Bloomington, Bolingbrook, Chicago, Decatur, Deerfield, Elgin, Eureka, Galesburg, Germantown Hills, Joliet, Kewanee, Lewistown, Lincoln, Lockport, Loves Park, Mendota, Metamora, Montgomery, Morton, Mundelein, Naperville, New Lennox, Normal, Oak Lawn, Ottawa, Pekin, Peoria Area, Plainfield, Pontiac, Princeton, Rock Cut, Rockford, Springfield, Streator, Urbana, Watseka, Waukegan and West Dundee.

Active Business Listing

Thermal Services, Inc. (TSI) is one of 12 HVAC companies ProsGrade lists in Peoria, Illinois.

Active

Public local listing

Listing details

12 services listed, including Commercial HVAC, Furnace repair and installation and Heat pump repairs. Open 24 hours, 7 days a week. Rated 4.9 from 50 reviews.

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Published local profile

How This Business Compares

How Thermal Services, Inc. (TSI) compares with the other 11 HVAC companies on ProsGrade in Peoria, using public Google ratings and review counts.

Rated 4.9 on Google, at or above the 4.8 average of other Peoria HVAC companies on ProsGrade.
One of 11 Peoria HVAC companies on ProsGrade rated 4.7 or higher from at least 10 reviews.

Services Covered

12 services

Commercial HVACRepairs, installation and maintenance for all system makes and models.
Furnace repair and installationElectric, gas and propane repairs; installations for all brands and models.
Heat pump repairsRefrigerant leaks, broken valves and electrical failures.
Air conditioner repair, installation and maintenanceAll kinds of air-conditioner systems and units.
Ductless split servicesRepairs to compressors and evaporators.
Generator servicesInstallation, repair and routine maintenance.
HVAC maintenancePreventative care for all heating and cooling brands and equipment.
Humidifiers and air purifiersWhole-house humidifiers; iWave air purifiers.
Boiler servicesRepair, installation and maintenance.
Chiller servicesRepair, maintenance and installation.
Geothermal unit repairsInspection, diagnosis and repair.
Commercial air compressorsProfessional and industrial grades available.

Reviews

What customers say

Customers praise prompt, courteous service; one customer also valued a clear explanation of the HVAC issue and respect for their time. One customer praised the cleanup after a geothermal-unit repair, while another credits Heath with responding quickly when their parents' furnace failed in winter.

Customer Reviews

Chris Jung

I’ve used TSI for routine repairs/inspection of my furnace. Heath is extremely knowledgeable and pricing is very fair. Because of the service they’ve provided me, they were the first ones I called when my parents furnace went out in the middle of the winter. I’m extremely thankful for how quickly Heath responded in this emergency.

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Drew Bailey

Had issues with my geothermal unit not turning on and freezing up. Called TSI and had someone out immediately. Excellent customer service, very polite and respectful. Diagnosed bad compressor and defective sensor. Ordered parts and installed as soon as they were available. Got everything dialed in and back up and running quickly. Excellent workmanship, left no trash, and cleaned up after themselves. I will definitely continue to use this company in the future! Bills were mailed promptly and were very reasonable. Great company and employees!

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Ian Bailey

I had a great experience with TSI! From start to finish, their team was friendly, professional, and genuinely respectful of my time. They showed up when they said they would, worked efficiently, and took the time to clearly explain what was going on with my HVAC system. What I appreciated most was their honesty. They didn’t try to upsell me on anything I didn’t need and were very conscientious about my budget. It’s clear they care about doing the job right and making sure their customers understand their options. Their knowledge and expertise really stood out, and I felt confident in the work being done. I recommend them to anyone in need!

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LaVonne Sammis Sammis

Our furnace would not start, within a couple hours TSI was here, found the problem and fixed it. He was polite, friendly and VERY professional! Highly recommend calling TSI for your HVAC and AC needs!

Joe Malone

The technicians, Dillon and Darrell, were very prompt, courteous, and professional. Dillon replaced my furnace. Darrell replaced my ac-unit. Both units required some extra work as they were very antiquated. It was clear that both men took no shortcuts and did honest and straightforward work. And they were here at separate times. Each took the initiative to keep me in the loop on any changes that needed to be made and gave me options and perspective when I asked them to talk me through decisions. Their answers focused on what would be in my best interests. The office workers, Trisha and Cheyenne, were courteous and helpful. They communicated well and promptly when I had questions about equipment and pricing prior to install.--High quality employees make the value of a company, and are becoming more and more rare. This company has found 4 high-quality employees.

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Frequently Asked Questions

Does TSI provide emergency HVAC service?

It provides 24/7 emergency service for residential and commercial customers.

What is included in TSI's residential maintenance agreements?

They include two HVAC inspections annually, plus emergency, after-hours and weekend service without additional rates.

How often does TSI recommend air-conditioner inspections?

It recommends at least one inspection each year, preferably in spring.

Can TSI help with Ameren incentives?

It handles paperwork to check eligibility for incentives on energy-efficient HVAC upgrades; qualified customers receive most incentives at purchase.