depends on the temperature of the outside air. Air conditioning provides better cooling but it is more complex and weighs more than a ram air system.
Piston powered helicopters use a heat exchanger shroud around the exhaust manifold to provide cabin heat. Outside air is piped to the shroud and the hot exhaust manifold heats the air, which is then blown into the cockpit. This warm air is heated by the exhaust manifold but is not exhaust gas. Turbine helicopters use a bleed air system for heat. Bleed air is hot, compressed, discharge air from the engine compressor. Hot air is ducted from the compressor to the helicopter cabin through a pilot-controlled, bleed air valve. 
 

ANTI-ICING SYSTEMS
Most anti-icing equipment installed on small helicopters is limited to engine intake anti-ice and pitot heat systems.
The anti-icing system found on most turbine-powered helicopters uses engine bleed air. The bleed air flows through the inlet guide vanes to prevent ice formation on the hollow vanes. A pilot-controlled, electrically operated valve on the compressor controls the air flow. The pitot heat system uses an electrical element to heat the pitot tube, thus melting or preventing ice formation.
Airframe and rotor anti-icing may be found on some larger helicopters, but it is not common due to the complexity, expense, and weight of such systems. The leading edges of rotors may be heated with bleed air or electrical elements to prevent ice formation. Balance and control problems might arise if ice is allowed to form unevenly on the blades. Research is being done on lightweight ice-phobic (anti-icing) materials or coatings. These materials placed in strategic areas could significantly reduce ice formation and improve performance.
 

5-12

Title 14 of the Code of Federal Regulations (14 CFR) part 91 requires that pilots comply with the operating limitations specified in approved rotorcraft flight manuals, markings, and placards. Originally, flight manuals were often characterized by a lack of essential information and followed whatever format and content the manufacturer felt was appropriate. This changed with the acceptance of the General Aviation Manufacturers Association’s (GAMA) Specification for Pilot’s Operating Handbook, which established a standardized format for all general aviation airplane and rotorcraft flight manuals. The term “Pilot’s Operating Handbook (POH)” is often used in place of “Rotorcraft Flight Manual (RFM).” However, if “Pilot’s Operating Handbook” is used as the main title instead of “Rotorcraft Flight Manual,” a statement must be included on the title page indicating that the document is the FAA-Approved Rotorcraft Flight Manual. [Figure 6-1]