Powdermill Village

Background

Built in 1972, Powdermill Village is a large property of 12 buildings and 250 units where oil was the primary heating fuel and electricity was used for heating domestic hot water. Annually between $320,000 and $400,000 was spent on heating. Efficiency and conversion options at this aging complex were first explored when gas became available on the street and service to the site was offered at no cost. Simple fuel switching comparisons between oil/electricity and gas identified sufficient savings to move the work forward.

Working with architects and mechanical engineers much needed HVAC, domestic hot water (DHW) and building envelope improvements were scoped out for this 40 year old property with the goal of bringing the performance of the property above prevailing code standards. A case in point was the antiquated electric hot water heaters that had estimated average efficiency rating of ~75%. The upgraded system would have an average efficiency rating of ~94% and with it considerable energy savings. These estimated savings along with several additional proposed improvements were sufficient enough to bring the project to a financial lender.

Solutions

Peabody Properties' approach was to complete one building in its entirety using high efficiency boilers, DHW storage systems and envelope upgrades that were known to the design team which would make the evaluations and modifications of the project an easier task. Based on the lessons learned during the renovation of the first building, tweaks to the design could be made and replicated in the remaining 11 buildings.

Envelope improvements, designed to reduce the existing energy loads, included 2-inch rigid insulation on exterior facing walls, triple glazed windows, fiberglass patio doors, insulated basement walls using 1 ½-inch insulation board. Accompanying this was a comprehensive air sealing strategy with blower door infiltration testing being conducted prior to construction and theatrical fog testing during construction to spot check air sealing effectiveness at doors and windows.

Other Benefits

Working with Mass Housing, Peabody Properties was able to modify the utility allowance for domestic hot water. The utility allowance revenue to the property is expected to be $76,000 annually. They have also eliminated capital and repair costs the property would have endured if the current equipment was to stay in place. These costs include new DHW in units valued at $162,000 and boiler repairs that currently cost the property $80,000 annually.

A combination of data loggers and sub-system meters will track the consumption patterns of the occupants and the performance results of the newly installed equipment for a period of two years in the first building that is renovated. The data will be used to optimize operations and maintenance practices so as to realize the full potential of the efficiency upgrades.

ANNUAL ENERGY USE

(Source EUI)

ANNUAL ENERGY COST

ANNUAL WATER USE

ANNUAL WATER COST

ANNUAL PLANT ELECTRICITY USE

ANNUAL PLANT ELECTRICITY COST

IN BUILDING ENERGY USE

IN BUILDING ENERGY COST

ACROSS NETWORK USE

ACROSS NETWORK COST

ANNUAL EMISSIONS

USE

COST

Site envelope work

Indirect domestic hot water storage tanks

Lochinvar wall-hung high efficiency boilers

Powdermill Village

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Site envelope work

Indirect domestic hot water storage tanks

Lochinvar wall-hung high efficiency boilers