A case study: how to make a plan for energy efficiency at your house


Larry Hepler, known to most Islanders as a furniture maker, is also the owner of Energy Conservation Strategies (ECS). ECS performs home energy audits and assists homeowners in developing game plans for systematic and cost-effective energy efficiency improvements. This essay examines the issues that confront most homeowners who would like to make their dwellings more efficient and less expensive to own. Part one of Mr. Hepler’s essay appears in Greening Martha this morning. Part two may be found online at mvtimes.com.

Many of us would like to make our homes more efficient and reduce our energy consumption. For good reason. On the Vineyard, we pay a lot more than other Americans to heat, cool, and power our homes.

Here are some examples:

In December 2009, the cost per kilowatt hour (KwH) of electricity was 6.30 in Wyoming, 22.10 in Hawaii and 22.0 on Martha’s Vineyard. The national average was 10.40.

In December 2009, a gallon of propane cost $1.72 in Iowa, $2.80 in Massachusetts, and $3.99 on Martha’s Vineyard.

That’s the bad news. The good news is that we stand to save considerably more through conservation, energy efficiency, and renewables than most Americans, and the payback period for investments we make is much shorter.

Even if you have conserving energy as a goal, it can be hard to know where to start. The first step is to make the commitment to getting started. Every house and family situation will be different, but there are logical steps to follow. Building science can involve the use of a lot of technical data and modem technology, but in most cases, you can make sound decisions with a basic understanding of how buildings and building systems function and a little common sense. Most often, you can make significant improvements with moderate effort at reasonable cost. Many energy-efficient purchases, weatherization work, and retrofits qualify for state or federal rebates or tax credits that can significantly lower the cost. Taking advantage of these programs is easy. You’ll need to invest a little time, some money, and some planning, but the payoff may come faster than you now believe and go on year after year, becoming greater as the cost of utilities increases.

An energy conservation case study

At the heart of energy conservation is an understanding of how efficiently we use any fuel. Throughout this case study, efficiency refers to the amount of the heat generated by any device (water heater, wood stove, fireplace) that goes into the water or into the room, as opposed to out through the walls of the room or up the chimney. I prefer the charm and ambiance of fireplaces to other methods of heating a room (I have two and use them daily in the cold weather) but they are only about 10 percent efficient. Most of the heat goes right up the chimney. I cut my own wood, so that is a lot of effort and fuel for a small amount of heat.

Several years ago, I decided to see just how energy-efficient I could make my Chilmark home. It was designed by me and built in 1985 by a very good and knowledgeable local builder. It is of modest size, about 1,200 sq. ft., not including the garage, with low ceilings. The heat is propane Monitor, augmented by wood stove and fireplaces. Most of the south wall is floor-to-ceiling glass with a 16-inch overhang for summer shading. Designed to take advantage of winter sun angles, the house has never needed daytime heating on sunny winter days, even if the outside temperature is in the single digits, but it was drafty and difficult to heat on overcast days when the outside temperatures went below 20°F. I knew some areas never had been thoroughly insulated, particularly the space that connects the house to a garage that was added later. We had some old clunker appliances and an assortment of electronics suitable to running two small home-based businesses. Even with energy-conscious habits, we were spending approximately $135/month for power and $1,800/year for propane.

Here is how I got from there to an electric bill of 17 cents last month and almost no use of propane this past winter.

First Step: Cape Light Compact assessment of appliances and lighting

The Cape Light Compact (CLC) (www.capelightcompact.org), covering all 21 towns of Barnstable and Dukes counties, administers local energy efficiency programs and negotiates electric rates on behalf of our region’s 200,000 electric customers. Through our NSTAR electric bills, we pay for services, including free home-energy assessments. The CLC representative who visited my home metered the appliances to check their power consumption. He found that our 10-year-old refrigerator, one of the bigger energy users in most homes, used about $380/yr in electricity. I received a $300 rebate coupon, good toward the purchase of a new refrigerator carrying the ENERGYSTAR label. The one I purchased costs about $115/yr to run at Vineyard electric rates (don’t believe the stickers on these appliances, given our high electric rates as mentioned above). The old refrigerator (cord cut and plug sent in with the coupon) was properly disposed of (coolants and toxic chemicals removed) for a small fee. After the rebate, the new refrigerator paid for itself in about three years worth of electricity savings and should last at least 10 years.

When we needed to replace or purchase other appliances, we chose ENERGYSTAR, and in the case of the clothes washer, selected a front loader that uses much less water than a top loader and is easier on the clothes.

The CLC agent gave us enough highly energy-efficient compact fluorescent light bulbs (CFLs) to replace most of the incandescent light bulbs in the house. Years later, those bulbs are still working. We turn off interior lights whenever possible and have switched to inexpensive solar lights for outdoor lighting.

Second Step: efficient woodstove

In the summer of 2008, talk of $4 dollar to $5 dollar-a gallon propane was in the air. Our propane bill had been about $1,800 the previous winter when the price was less than $3/gallon. We relied on an inefficient 20-year-old Vermont Castings wood stove for supplemental heat in the coldest months. A visit to Vineyard Alternative Heating taught me that new wood stoves were 75 percent to 80 percent efficient and cost about $1,400 after a 30 percent federal tax credit. The new stove heated the house so well that I was able to turn off the propane heater, allowing us to be very comfortable using only wood heat and saving nearly the entire cost of the new stove in the first winter.

Third (Big) Step: comprehensive energy audit

In conjunction with the new stove, Vineyard Alternative Heating advised that I get a comprehensive home energy audit. The audit by Adam Hayes, then one of the few trained energy auditors on the Island, was so impressive that I subsequently received training to become an energy auditor and energy rater and now provide this service.

An energy audit includes a blower door test, the only reliable way to measure air leakage into the house and locate the leaky spots. A fan device is inserted into an exterior door and blows air out (depressurizes the home) so that it is easier to feel where air is leaking in. Then there is an assessment of the location and adequacy of insulation, and an assessment of the efficiency of mechanical equipment such as the water heater, along with the electrical metering of appliances and electronics.

An energy audit generates a list, or map, of the leaks and a prioritized list of improvements, starting with those problem areas that can be most easily corrected at the least expense for the greatest benefit — the “low hanging fruit” — and most homes have more of it than their owners realize. The list also includes more significant improvements, with bigger price tags and/or potential for disruption, that might take longer to pay back in energy savings. You might think your problem is old windows and the high cost of replacement causes you to throw up your hands, but a blower door test might show that you could make cost-effective progress by plugging small leaks and leaving the expensive window project for later.

How did the energy audit turn out for Mr. Hepler, and what did he do with the results? What would an energy audit reveal at your house, and what might you do? Part two of Mr. Hepler’s helpful essay follows:

Greening Martha: A case study: how to make a plan for energy efficiency at your house

By Larry Hepler

Part Two

The bower door test showed that the air inside my house was changing at the rate of 83 percent per hour. Every hour I was heating, 83 percent new, cold, dry air replaced the air I was heating, when the recommended air exchange rate is 35 percent per hour. You don’t want any house to be totally air tight unless it is equipped with a whole house ventilation system. The test identified most of the leaks, and I received recommendations for caulking, weather stripping, sealing recessed lighting fixtures and areas around the electrical panel, chimney chase, attic access, etc. Dampers at the stove vent, dryer and bath fan were stuck open or missing, allowing cold air to blow directly into the interior. In my subsequent work auditing other Island homes, I have discovered that my situation was far from unique. In fact, in my training I learned that the aggregate leakage in most houses is equivalent to an open window.

I have made most of the air leakage improvements myself, spending four or five days caulking, installing new weather stripping and sweeps on doors, installing dampers and sealing with foam caulk and flashing. While I now have a variety of sources for the materials I use when weatherizing clients’ homes, I did my own home with materials easily available at Island hardware stores.

Fourth Step: improving insulation

The audit verified what I suspected: the attic insulation was inadequate, and the crawl space and mudroom/entry floor insulation was non‑existent. Armed with this knowledge, I tapped into CLCs insulation program whereby it does an assessment and, if it determines your insulation is inadequate, it will perform the work and absorb up to 75 percent of the cost, to a total of $2,000. After I did a little prep work (that attic needed a good cleaning anyway), CLCs very efficient installers blew nine inches of cellulose into the attic eaves and over the mudroom/laundry and installed fiberglass insulation to the floor bays over the crawl spaces. Including a bit of optional work I requested, the cost to me was $538. The insulation work raised the average R-Value by which insulation is measured in the attic from about R-24 to the recommended R-48 and in the floor from zero to R-25. The change in comfort and ease of heating was immediately apparent.

Now, for the results. We are reaching the end of our first winter with the new wood stove and a tighter, well insulated house that is more comfortable and much less drafty. The stove heats the house well without any propane, which we use only when we are away. We have saved most of the cost of the improvements in less than two years and reduced the heating bill to less than $200/month (including the cost of the new wood stove and a putative “salary” for me to split and stack the wood).

Fifth Step: monitoring electrical consumption

Our hot water heater, stove burners and dryer run on propane. Even with conscious energy conservation, the rest of our needs – well pump, refrigeration, oven and kitchen appliances, clothes washer and home and office electronics (even when replaced it with new ENERGYSTAR devices as each one died) – were still adding up to an electric bill averaging $135/month.

After stopping air leakage, we were able to remove the humidifiers for a big saving. We had been using two or three humidifiers continually whenever the heat was on to combat dry skin and sinuses in winter. A heated home equals dry air, right? Wrong. What I learned is that humidifiers use a lot of power (about the equivalent of running a hot plate 24/7) and that cold air, not home heating, is to blame for dry air. I found it hard to believe myself, but if you stop all that cold, dry air from leaking in, the dry air problem disappears. We stopped using humidifiers and have not suffered from dry skin or nasal passages since.

I also metered the TV, DVD and other electronics and found that they used about $40/year in electricity – when they are turned off. Many current electronics and appliances have little lights, clocks and other glowing bits you can see. Even with nothing lit, some electronics sit in a ready state so they can spring to action when we press the on button. They are drawing current (called a “phantom” or “ghost” load) even when supposedly off. I plugged these devices into a “smart strip” that cuts the power usage at the wall.

Sixth (Big) Step: installing photovoltaic system

Wanting to reduce both our electric bill and our use of fossil fuel generated electricity even further. We took the plunge into photovoltaics (PV) and installed a 2,650 volt, 16-panel solar system. People said at the time, and continue to say, “It doesn’t make sense to install a solar system. It’s just too expensive.” I don’t agree.

We had excellent help from Kate Warner of Vineyard Energy Project who not only designed the system and oversaw its installation, but also helped us navigate a state rebate program that paid about 40 percent of the cost of installation (and continues to send us modest quarterly rebates). The entire system, installed, cost about $11,600. It has reduced my electric bill to an average of about $20/month, for a savings of about $1,300/year. At current Island electric rates, the payback period will be less than nine years (assuming no increase in rates. How likely is that?). Maintenance costs on the system have been a total of $100 in four years. The projected lifetime of the system is 20 to 30 years. By my math, the system will pay for itself two to three times, or more, over its lifetime. But I’m not done yet.

Future steps: domestic hot water

The water heater is one of the biggest energy consumers in the home. Unlike some appliances and equipment, stand alone water heaters last only about eight years because of corrosion, and once the tank springs a leak, the whole unit must be replaced. With the Vineyard’s high energy costs, we stand to gain much more than most Americans by installing the most energy efficient water heaters we can afford. Options range from $400 to over $2,000. However, the cost of the water heater itself is only a small fraction of the cost of heating water. My energy cost (for a two-person household) is $80 to $100/month using a fairly good propane heater that barely meets ENERGYSTAR specifications and would cost about $800 to replace. I decided I wanted the most efficient heater I could find and was willing to pay twice that for a unit that was going to be much cheaper to run.

Solar hot water can be a great first step into conserving energy through renewables for many homes. A PV system can power a traditional hot water heater or a tank-less, on-demand water heater, where none of the energy used to create the hot water is dissipated before the water is drawn. Because we already have the PV system, I decided to install an electric heat pump hot water heater, which can save as much as 75 percent in energy costs. Heat pumps use proven, 30‑year‑old technology that works like a refrigerator in reverse. They are made by several of the best established water heater manufacturers but have not been marketed in the US until recently, except in parts of Florida and Hawaii where the high cost of electricity makes them popular.

I admit this is a bit of an experiment. I may need to expand my PV system to accommodate the demand of the water heater, but I am planning to do that anyway when I can buy an electric car that I can charge at home from the sun. I have been using an electric utility vehicle for work on the property and neighborhood transportation for years. I like to say that it runs on sunshine.