Northport: Deep energy retrofit

This profile is part of a showcase of Maine retrofits. Learn more and see the rest of the profiles here

Photos courtesy of Ecocor

Photos courtesy of Ecocor

RENOVATED TO Passive House EnerPHit standards, this 2,890 sq ft Northport home, owned by Chris Corson of Ecocor and his wife, Alexa, is a great example of what is possible in a deep energy retrofit. Ecocor is a design, construction and manufacturing firm specializing in high-performing homes that use certified Passive House components (manufactured at their facility in Searsmont, Maine). The goal of the retrofit was to get as close to Passive House standards as possible. Corson’s project now meets and exceeds those standards and is in the process of obtaining the EnerPHit certification, a quality standard given to refurbished buildings that meet similar, though not as stringent, measures as Passive House.

The Corsons retrofitted their home in two phases, beginning in 2010. In the first phase, they upgraded the home to Passive House standards and added a small mudroom. The second phase involved finishing the basement, which expanded the home to 2,890 sq ft.

When Chris and Alexia purchased the house in 2005, heat and hot water were provided through an oil boiler that used 1,680 gallons of oil per year at a cost of $4,700 (at $2.80/ gallon).

Over the course of the renovations, the oil burner was replaced with an air source heat pump hot water heater that is now piped to the existing hydronics system. Heat and hot water costs today? Less than $400/year, thanks in part to electricity that is provided by a 5.3 kw PV solar system. These results are achieved through triple-glazed windows, remarkable insulation and air sealing. A Zhender Comfo Air 350 heat recovery ventilation system ensures a steady supply of fresh conditioned air.



Why we like it: Chris has been a leader in high performance building for years, so it’s no surprise that his own house pushes the boundaries of what can be achieved in a renovation. This project combines cutting-edge technology with best practice building techniques, carefully applied. Chris monitors his projects closely, so we look forward to hearing what he learns about his home as time goes on.


EFFICIENCY: Built to Passive House EnerPHit standards. Plans for net-zero. Heat/how water costs average $33/month (less than $400/year).
BUILDING ENVELOPE: Slab—R-25, Foundation—R-31, Walls—R-47 to R-53, Roof—R-70 to R-100, Windows—R-10, Airtightness—.45 ACH50.
SYSTEMS: Heating and cooling—heat pumps, Sanden ASHP Combi System hot water heater (first in cold climate), air conditioning-Mitsubishi MUZFE 12NA ASHP. Ventilation—Zendher Comfo Air 350 ERV.
RENEWABLES: 5.3 kW solar PV
SIZE: 2,980 sq ft
COST: undisclosed


DESIGNER & BUILDER: ecocor/Chris Corson
ENERGY SYSTEMS: Solar Logix/Josh Oaxley
AIR SEALING & INSULATION: ecocor/Chris Corson


This article was reprinted from the spring issue of Green & Healthy Maine Homes magazine. Subscribe today!