Angie's LIST Guide to
Hiring an HVAC service

The awkward-to-pronounce acronym stands for "heating, ventilation and air conditioning" which in many respects are completely different processes.


An HVAC expert needs training in both electronics and plumbing. (Photo submitted by Angie's List member Dave M.)
An HVAC expert needs training in both electronics and plumbing. (Photo submitted by Angie's List member Dave M.)

HVAC experts

A few decades ago, before home air conditioning, the job was simply "furnace repair" and even ductwork was an afterthought since heat rose naturally and air flow was only marginally understood. Today, ventilation has become a technology of its own.

The heating and cooling system is one of the most complex systems that can be found in a home. It's essential that the HVAC service provider you hire is well-trained to deal with the inherent safety issues in heating systems -- electricity, natural gas, oil -- or cooling units that use toxic refrigerants such as Freon.

Many states that license HVAC contractors require that the applicant have a minimum amount of on-the-job or training experience, typically 2 to 5 years, working with HVAC systems.

That experience is critical since an HVAC contractor will likely need to have a competent understanding of how things like electrical wiring, refrigerant and combustion systems, and airflow through heating ducts all work together to add heating or cooling comfort to a home. Not only is comfort important, but safety is critical – knowing the proper operation of home ventilation and exhaust systems when working with a furnace can be the key to prevent death or injury from events like carbon monoxide poisoning, which can occur if an HVAC system is malfunctioning or improperly installed.

Checking licenses

Many states require HVAC contractors to be licensed and many state governments offer license look-up websites where you can check the status of a HVAC contractor's license.  It's also often the case that individual cities and municipalities have their own specific requirements for HVAC contractors.

The Angie's List staff maintains an online database of contractor licensing links to these state and local government websites.

Since heating and cooling work may also require repairing or installing plumbing to supply oil or natural gas to heating equipment, an HVAC contractor may also be required to hold a separate plumber's license or have a licensed plumber on call. However, some jurisdictions license HVAC contractors specifically for this line of work. When getting an estimate, be sure to ask not only if a company is licensed, but also what type of license it holds.

Questions to ask

If your furnace has just died in sub-zero temperatures or your air conditioner has gone kaput on a sweltering day, you'll probably be glad to hire the first repairman who can come to your house that day. But, if you're planning a major or costly upgrade to your home's heating, air conditioning or air ducts, it's worth the time to research and interview several companies before hiring one.

When interviewing candidates, don't forget to ask about:

Licensed, bonded and insured: Many states and municipalities mandate that heating and cooling contractors meet minimum education and on-the-job experience requirements, as well as pass written exams in order to be licensed to work in the heating and cooling industry.

In order to qualify for and continue to hold that license, HVAC companies frequently need to hold a minimum level of insurance and bonding. Any professional that works in your home should carry liability insurance to protect the homeowner in the case of accidental damage or injury.

References: A professional heating and air conditioning company should have a list of recent customers that you can refer to in order to verify that the company in question performed the work in a timely manner and to the customer's satisfaction. It's important to actually call those references to get relevant details about how their projects fared.

Estimates: Due to the high cost of repairing, replacing or installing new HVAC equipment, it's essential to get at least three written estimates from three different companies.

The project's cost is likely your most important consideration – and costs may vary widely from one company to the next - but it's also very important to ensure that the project's overall scope, details and completion dates are thoroughly documented.

Brands carried: When seeking estimates for new or replacement heating or cooling equipment be sure to ask prospective companies what specific manufacturers or equipment brands they carry. Unlike other home improvement contractors, HVAC companies often only carry a small selection of brands. If you're doing your own price comparison research on new equipment, you may need to limit your hiring choices to companies that specialize in your equipment brand of choice.

Experience with your system: If your heating or cooling systems features cutting-edge energy-efficiency design, such as a geothermal system, or relies on an old-school operating system, such as steam-driven radiators, make sure the company you choose has relevant experience with your particular system.

Tax credits or rebates: Depending on the type of home heating or cooling equipment you're installing or upgrading, your project may qualify for federal or state tax credits or rebates. Be sure to ask about what incentives are available for your project and make sure the project is properly documented to meet federal, state or local incentive requirements.

Payment schedule: On a big job, especially when installing new equipment, you may need to make a deposit and make progress payments or planned payments to satisfy the bill. If you use a payment plan or apply for financing through the HVAC company's line of credit, make sure you read all the fine print and know what you'll be financially responsible for.

Service contracts: If you're hiring a company for maintenance or having new equipment installed, enrolling in a service company's service contract program may give you added peace of mind. Service contracts are just that, a contract that ensures your HVAC system is serviced regularly by the company.

While having your equipment professionally maintained on a regular basis may extend the useful lifespan and improve its efficiency, as with any contract, make sure you know what you're paying for.

Find a provider

When you're ready to hire an HVAC expert for maintenance, repairs or a new installation, you can use the Angie's List database of service providers to look up your city and see the ratings other Angie's List members have given specific service providers in your area. Join Angie's List for access to customer reviews and ratings.


Unit was bought & had a contractor install it. 2 months later it stopped working. Had a few estimates & they said the compressor wasn't working. Now I need to have compressor deinstalled & sent to MFG. The mfg claims they don't cover labor. Had high priced techs.
Don't know now I heard a company over star 99.1 but they are away now. Trying to get them but never thought to ask for references.

In NJ there is NO actual HVACR license for contractors. We are titled under Home improvement contractors in Dept ofConsumer affairs governed by Attorney General office.
The only license a HVACR contractor needs to work on HVACR equipment is a Universal Refrigerant license by EPA. Without that license he cannot work on or purchase any HVACR equipment that contains refrigerant.

Customer purchase of HVACR equipment is also prohibited. Since the Condensor (which contains the compressor) was bought by customer it breaks laws since the condensor contains Refrigerant of R 410 A . Person needs EPA license to purchase that equipment. It is a major violation to sell equipment with refrigerant to non licensed person, with fines up to $38,000. R 22 Condensors come dry (without refrigerant) charged with nitrogen. Customers should be very aware of what they are buying , from who, and what types license they are displaying.

You have to be certified like myself 608 Universal and Certified in R410A like myself in order for the manufactor to cover the warranty.

While checking contractor licesnse status is a given (assuming your state has a licensing requirement), it is also a good idea to ask your contractor about certifications held by individual certfications. Certified HVAC technicians (whether it be UA STAR, HVAC Excellence, NATE, etc.) have demonstrated a level of competence within their trade and gives you more assurance that your job will be done correctly.

Additionally you should also ask contractors about which trade associations they belong. Typically contractors who join such associations are more dedicated to their profession than "non-joiners."

Finally, make sure that your contractor is familiar with industry standards that codify "Quality Installation" and "Quality Maintenance. The Air Conditioning Contractors of America ( have established the following standards: HVAC Quality Installation Specification ("Standard 5") and Maintenance for Residential HVAC Systems ("Standard 4") which have been vetted through the ANSI review process. Professional contractors will follow such standards.

The picture shown for a HVAC professional is ironic. He is working around equipment without safety glasses which is non compliant with OSHA standards and if he was trained would be required to know this.

I want to calculate size for AC unit; If 1 hp is equal 2544.43 BTU/hr, how come it said (in HVAC "world") that 1 HP is able to remove about 9000 BTU/hr? Isn't 9000 BTU/hr equals to 3.5 hp? (9000 / 2544.43 = 3.54)

Will appreciate detail answer.


To calculate heating/cooling load for the house you need to calculate by tons of refrigeration, not by hp. 1ton of refrigeration is 12000 btuhs. Therefore if say your existing unit is 3 ton(usually has 36 number on the cover plate), then it is capable of removing 36000Btuhs per hour. To properly size unit for your house many factors must be taken into consideration - wall insulation R value, ceiling insulation R value, quality and size of windows, even color of roof shingles - all these factors have huge impact on proper HVAC load calculation(and many many more). Easy trick - to determine if your AC is oversized for the house watch how it works at the design temperature day(93 degrees F for Wash DC area) - on a design temperature day AC unit should run non-stop in the afternoon-3pm. If it cycles - starts and stops, starts and stops - then it is oversized. BTW, absolute majority of houses in US have oversized AC systems and undersized ducts.
Mikhail Kurylenak, Master licensed HVAC tech in state of VA.

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