Dometic EnviroComfort ECD6KZ-HV AC Retrofit Kit - 6,000 BTU - 230VEnviroComfort ECD6KZ HV AC Retrofit Kit 6,000 BTU 230V The Dometic Marine Air 6,000 BTU EnviroComfort Air Conditioning Retrofit Kit provides reverse cycle cooling and heating capability so you stay comfortable onboard year round. This 6,000 BTU unit replaces an older self contained air conditioner of comparable capacity in the 5,000 to 7,000 BTU range. All units have high velocity blowers with internal motors for a more compact installation footprint.