A-All Plumbing, Heating and Air Conditioning
- Based in
- Lynbrook, Nassau County
- 4.8 from 431 reviews (Oct 2026)
- Hours
- Open 24 hours
- License
- Not checked yet. Look it up
HVAC Companies in Nassau County
Heating and cooling shops with a Nassau address, from Lawrence up to Jericho, sorted by township. Each card links to Nassau's license lookup.
Each company here showed up on Google Maps with a Nassau address in our October 2026 snapshot, and the stars and review totals are from that day. We do not rank or vouch for anyone. If a company pays for placement, its card says Featured.
Two levels of government license the work in Nassau. The county’s Department of Consumer Affairs licenses the company that sells and installs your boiler, furnace or central air, because the county counts that equipment as home improvement. The plumber who runs the gas or water line answers to the municipality, since Nassau leaves plumbing and electrical licensing to the towns, cities and villages. To look up either, start with our guide to checking a license.
If money is the barrier this winter, HEAP and the HERR repair benefit for homeowners 60 and older are applied for through Nassau’s HEAP office, which OTDA lists on its contacts page.
Nassau heating and cooling contractors, by town
Town of Hempstead3 contractors
24/7 HVAC of Long Island Inc
- Based in
- Lawrence, Nassau County
- 5.0 from 147 reviews (Oct 2026)
- Hours
- Open 24 hours
- License
- Not checked yet. Look it up
Long Island HVAC Repair LLC
- Based in
- Levittown, Nassau County
- 5.0 from 18 reviews (Oct 2026)
- Hours
- Open 24 hours
- License
- Not checked yet. Look it up
Town of North Hempstead1 contractor
T.F. O'Brien Cooling & Heating
- Based in
- New Hyde Park, Nassau County
- 4.9 from 2,533 reviews (Oct 2026)
- Hours
- Mon-Fri 8am-5pm
- License
- Not checked yet. Look it up
Town of Oyster Bay1 contractor
Home+ Air and Heat
- Based in
- Jericho, Nassau County
- 5.0 from 119 reviews (Oct 2026)
- Hours
- Open 24 hours
- License
- Not checked yet. Look it up
Hiring in Nassau County
What license does a Nassau HVAC company need?
The county's home improvement license, which by Nassau's own definition takes in the installation or replacement of central heating and air conditioning. Nassau also fingerprints every licensed home improvement contractor.
Does Nassau County license plumbers?
No. Plumbing and electrical licenses in Nassau are local, issued by your town, city or village. If a heating job includes gas or water lines, ask the company who does that part and under which municipality's license.
Where do I report a gas smell in Nassau?
National Grid handles natural gas emergencies on Long Island. Go outside and call 1-800-490-0045 or 911.
Sources, checked October 2026