Are you looking for just forced air combined heat and cool? My parents are running an oil-fired boiler for more than 50 years. It heats the house and makes hot water for the faucets. It originally had one zone, but now has three. The burner has been replaced a time or two.

Last week we installed a unit to replace a 4 ton ac system, no brand name on unit, but there was a tag inside giving name of installing company and date 6/17/69 that,s 41 years. The condensing unit was made in Jackson Michigan, has a big old Tecumseh compressor, looks to be the original, the A coil looks orignal, built like a tank was installed in a Montgomery Wards 100,000Btu furnace.6/17/69 Incidentally unit still worked. Homeowner simply wanted to install a more effecient furnace & ac. Home owner had lived in house since 77 and the company on tag is no longer listed in phone directory. Owner said the only ac repair was replacing the conderser fan motor about 10 years ago. Said also replaced furnace blower motor 4 years ago and main gas valve a few years back.

Stuff then was built to last, not built as cheap as possible as that's what homeowners want.

Oldest we've removed besides an ancient steam boiler was Carrier units from the 50s. Condenser had a blower, semi-hermetic compressor, used Carene 7 refrigerant (aka R500). One even was still working.

iggie's outdoor unit was a Heat Controller, the Wards furnace was made by Rheem. Wards even sold a 2 stage furnace in the 70s. Staged by 2 stage stat or a switch on the stat that said high/low.

Thanks Lonnie some very interesting info, one of the other tech told me about a job he preformed before coming to work at our firm. Said he Removed a Chrysler Air temp unit that had been installed in 57 was still working.

we have wards ac unit. janatrol furnace. 1974. gas bill is ok. elec bill is 200+ which seems high for MN a/c use. a/c does cycle on/off though. but house never gets much below 78F. removes moisture quite well.

The original Carrier Model 1 Air Conditioning installed in the Williamsburg (VA) Theater operated 67 years until the building was gutted in 2000.