JMG Heating and Cooling

JMG Heating and Cooling is an HVAC business with a 5-star Google rating from 42 ratings and an A grade from the Better Business Bureau. A Maine hvac license, number MS30020120, is active on the state registry, with JONATHAN B. KARKOS as the holder of record. One recent customer said Jon replaced an old boiler and installed a couple of new heat pumps, and was very open about what he was doing. A customer who needed urgent help with a heating system said JMG arrived within sixty minutes, and that Jon fixed the issue quickly and did not recommend unnecessary upgrades. A heat pump customer said Jon explained why the units needed a deep clean and showed them the dirt coming out of the inside. A customer who had a new efficiency boiler system installed said Jon, his brother Paul and crew member Josh left everything working properly and cleaned up. A 2026 customer who called for no heat on a Sunday night said he was there in under an hour and fixed what Fabian couldn't in 20 minutes. In a 2026 review, a customer whose boiler failed around 9:00 PM on a Wednesday said JMG called back right away, inspected the unit the next morning and installed a new boiler. A 2026 customer described a bigger job in which Jon and Gavin replaced a non-functioning oil furnace with a new propane furnace and water heater and added a new heat pump; that customer said the price matched the estimate.