Space-heating improvements in multi-family buildings. Final report, October 1984-October 1989

The final report presents the results of research on cost-effective energy efficiency improvements for existing low to moderate income multifamily buildings heated by gas-fired single pipe steam systems. Analyzed measures include indoor thermostats, main line vents, radiator vents, boiler derating, vent damper. Eleven buildings were instrumented and monitored over a three-year period to document the effect of the test measures on boiler gas usage, tenant gas and electricity usage, and indoor temperatures. The results indicate that proper specification and installation of thermostats, main line and radiator vent treatments and derating can result in 20% savings in annual space heating costs for a capital investment of under $200 per unit and a payback of under three years. They are applicable to almost all single-pipe steam heating buildings. They also can improve tenant comfort and reduce the tenant-borne expense of supplemental heating. Updated procedures are included for specifying and implementing the thermostat and vent treatments and for measuring their performance and boiler seasonal efficiency.