Showing posts with label Carbon Foot Print. Show all posts
Showing posts with label Carbon Foot Print. Show all posts

Friday

Retrofit reduces energy use by 60 percent

Pilot Project Super Insulation for Older Homes at Massachusetts home
You could call it an "Extreme Makeover: Energy-Efficient Edition."


In Arlington, Mass., Alex Cheimets and Cynthia Page live in a duplex that used to consume about 1,400 gallons of heating oil a year. Now their building will soon be one of the most energy-efficient in its New England neighborhood, thanks to a pilot project that retrofitted the structure with almost $100,000 worth of insulation and other products to increase energy efficiency and decrease utility costs.

The so-called Massachusetts Super Insulation Project seeks to determine the benefits and cost effectiveness of retrofitting old energy-wasting houses with insulation upgrades in key areas. Though the cost for the upgrades in the home were substantial, some of the techniques used—such as proper air-sealing and adequate moisture barriers—could easily be applied to new construction and for not much more money.

Massachusetts officials are keenly interested in the results of the project, which dovetails with the state’s efforts to become more energy-efficient. “Our governor, the state House and Senate, and the executive branch are aware that the nation’s energy strategy is not acceptable, and a big part of it is the existing housing stock,” says Philip Giudice, commissioner of the state's Department of Energy Resources.

“Nationally, buildings account for 40 percent of all energy consumption and one-third of all greenhouse gas emissions,” says Energy and Environmental Affairs Secretary Ian Bowles, who chairs Massachusetts Gov. Deval Patrick’s Zero Net Energy Buildings Task Force. “This super-insulation project in Arlington promises to be a model for the type of innovation in the building industry that the Patrick administration hopes will soon be widespread across Massachusetts.”

The public/private effort includes the state Department of Energy Resources, the local utility NStar Electric & Gas, and a number of building product sponsors.

Bowles is right, of course. As green building practices spread through the new construction market, America’s existing housing stock remains an energy-use problem. Millions of these old structures lose large amounts of energy through leaky windows, inefficient heating and cooling units, and poorly insulated walls, all of which contribute to higher-than-necessary utility bills. The 3,200-square-foot Cheimets/Page building—divided into one condo for Cheimets and his family and one for Page—was one of these structures.

At one point when home heating oil in the Massachusetts area hit $4.69 a gallon, Cheimets says, the homeowners were paying a combined total of almost $6,500 a year for heating and hot water. “We needed to replace our siding and our roof soon anyway,” Cheimets says. “As a duplex, we could simply do the minimum or we could invest now to save later. Super-insulation was the better financial investment.”


The parties in the pilot wanted to demonstrate that it’s possible to bring an existing building up to the highest standards of energy performance. In addition to reducing energy use by between 65 percent and 70 percent, the group was also interested in exploring super-insulation as part of an overall program of energy efficiency and carbon reduction. Finally, it hoped to use the Arlington, Mass., pilot project to determine cost-effective retrofit recommendations for homeowner renovations; develop experience with and collect performance results for existing structures; and establish criteria for future state programs supporting residential super-insulation projects.


Before the work commenced, the project team consulted with Somerville, Mass.-based Building Science Corp., which performed energy parametric simulations, analysis, and economic payback comparisons of various energy retrofits options.

As a result, the extensive retrofit focused on tightening the building envelope, which included new doors and the replacement of the single pane windows. The team installed double-pane Pella fiberglass windows with low-E glazing, Tyvek stucco wrap, two layers of 2-inch Dow closed-cell foam board, furring strips, and NuCedar cellular PVC siding. They ripped off the old roof and installed two layers of 3-inch foam board on the roof deck, followed by plywood sheathing, and light-colored asphalt shingles. They also sprayed Icynene open-cell foam in the attic roof and in the basement rim joists and ceiling. Finally, the team installed a heat recovery ventilator and an on-demand water heater.

Cheimets says the upgrade have made a big difference in the comfort level of the units and in the performance of the building. “I felt the difference immediately,” he says. “There are fewer drafts and no cold spots; that’s all gone away, and we have seen about a 60 percent reduction in energy use.”

As part of the pilot project, DER and NStar have installed sensors to monitor real-time oil usage as well as temperature and humidity levels inside and outside the house. “We were using about nine gallons a day before, but now we’re using three on average,” Cheimets says.

The reduction in the building’s ongoing energy use has come at a steep one-time price tag. Overall, the retrofit cost more than $90,000, and like most renovation projects, ended up being more expensive than expected in different areas.

For example, the cost for the roof replacement was first estimated at $10,000, but the price tag nearly doubled by an additional $9,000 with the addition of super-insulation. Replacing the siding was projected to run $30,000, but it increased by $41,000 with super-insulation and re-flashing the windows. An additional $6,000 went toward the installation of expanding foam in the basement ceiling; $4,000 paid for heat recovery ventilators.

“If you look at the additional cost of super insulating (compared with just doing the required work in ‘standard’ fashion) doing this work is an additional cost of $50,000, or $25,000 per family” in the two-unit duplex, according to program documents.

While the costs are high, Cheimets says they should be taken in context of retrofitting an 80-year-old house that featured 50 windows and suffered from bad insulation from the start. Doing such upgrades in new construction would be cheaper. “If you’re building a new house, you would be taking certain things into consideration like facing the roof south, using fewer windows, and decreasing the amount of angles in the roof,” he says.

John Dennis Murphey agrees that using such strategies would absolutely make such a remodel cheaper. “That’s what we’re doing now on one house,” says the principal of Chevy Chase, Md.-based Meditch Murphey Architects.

There are also other ways to save money on such a project. Murphey, for example, has eliminated conventional sheathing from his houses all together. Instead, he uses 2 x 6 studs, spray foam insulation, and metal bracing to make the studs rigid. “The studs are energy highways,” he says. He then wraps his houses in 1.5 inches of foam board, which creates a thermal break.

Instead of simply balking at the added costs, though, Murphey says builders and consumers should look at the overall project and the long-term benefits. “Energy prices have come down, but who knows where the price of oil will go,” he continues. “My bet is that they will go up. I’ll take that bet every time.”

Members of the Super Insulation Project would probably agree. It is estimated that the annual savings to the homeowners will be $2,350 to $4,000 per year. “At the current heating oil cost of approximately $2.35 a gallon, it's a 20-year payback,” program documents say. “But a few short weeks ago the price was closer to $4 a gallon, and the price of oil is likely to rise again in the coming years, dramatically shortening the payback period.”


By:Nigel F. Maynard, Senior Editor, products, at BUILDER magazine.
Contact scotty@stlouisrenewableenergy.com or scottscontracting@gmail.com for your Green Building Needs.  Addition Green Building information can be found at http://www.stlouisrenewableenergy.com/

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