This document summarizes energy efficiency upgrades made to Pleasant Street Apartments in Enosburg Falls, Vermont. The 24 unit apartment complex had individual heating and hot water systems using over 15,000 gallons of propane per year. Upgrades included air sealing and insulating the building envelope, installing mini-district heating with wood pellet boilers and solar thermal collectors, and switching to efficient ventilation and circulator pumps. These measures are predicted to reduce annual fuel usage by 30% and costs by almost 70%, lowering the cost per unit month from $156 to $46 with support from various project partners.

1. Pleasant Street Apartments
Enosburg Falls, Vermont

2. Pleasant Street
Existing Conditions
• (24) - Units of Family Housing
• (6) Detached buildings, slab on grade, late
1980’s construction
• Individual heating and hot water systems,
propane as primary fuel
• 15,000 gallons of propane per year
– 625 gallons per unit
– $156 Per Unit Month (PUM)

3. Building Envelope
• Air seal and insulate attic plane to R-60
• Two part spray foam of “leaky”
construction components, overhangs,
penetrations, etc.
• Continious taped 1” of XPS on walls, R-5
• New R-3 double hung windows.
• Care and detail to airsealing

4. Envelope Retrofit

5. Mechanical Systems
• Individual heating systems were converted
to (3) semi-central mini-district heat.
• Primary heat and hot water by Froling
wood pellet boilers, supplemented by solar
thermal hot water collectors.
• A common 200 gallon storage tank buffers
the biomass boilers, and augments the
solar storage.

6. Mechanical Retrofit

7. Froling Pellet Boiler
• Auto Start
• Self Cleaning
• Built in Controls
• Onboard pellet
forwarding
• And yes… It can
make espresso!

8. Additional Mechanical Measures
• ECM circulator pumps, uses 65 – 80%
less electricity than traditional systems.
• Constant mechanical ventilation in each
unit, using Panasonic Whisper Greens.
• Use of microprocessor controls to regulate
loop temperature, warm weather shut
down and domestic hot water priority.

9. Project Performance
• Air tightness, as tested by blower door,
below new construction targets.
• Predicted fuel usage to be around 55 tons
of wood pellets per year.
• At current pellet costs, a Per Unit Month of
$46, over a hundred dollar reduction.
• A 30% reduction in MMBTU and almost a
70% reduction in Dollars.

10. Project Partners
• USDA – Rural Development
• VHCB – Vermont Housing and
Conservation Board
• CVOEO – Weatherization Agency (WAP)
• EVT – Efficiency Vermont, EEU
• CEDF – Clean Energy Development Fund
• In addition to traditional housing sources

11. Questions?
Trevor Parsons
Housing Vermont