Southwest Garden Neighborhood Energy Trust

Useful Links & Downloadable Information

Determining Peak Hot Water Demand.pdf
Federal
US Environmental Protection Agency - energy conservation
HUD - Green Retrofit Program for Multifamily Housing 5-13-09.pdf
US Department of Energy - energy and efficiency tax programs
US Green Building Council - St. Louis Chapter
State
Missouri Department of Natural Resources Energy Center
Local
Earthways Center - Missouri Botanical Garden
Laclede Gas Energy Efficiency Program
Ameren UE Renewable Energy Initiatives

Energy Efficiency Primer

Energy Audit

A home energy audit is the first step to assess how much energy your home consumes and to evaluate what measures you can take to make your home more energy efficient. An audit will show you problems that may, when corrected, save you significant amounts of money over time. During the audit, you can pinpoint where your house is losing energy. Audits also determine the efficiency of your home's heating and cooling systems. An audit may also show you ways to conserve hot water and electricity. You can perform a simple energy audit yourself, or have a professional energy auditor carry out a more thorough audit.

A professional auditor uses a variety of techniques and equipment to determine the energy efficiency of a structure. Thorough audits often use equipment such as blower doors, which measure the extent of leaks in the building envelope, and infrared cameras, which reveal hard-to-detect areas of air infiltration and missing insulation.

Space Cooling and Heating

Heating and cooling account for about 56% of the energy use in a typical U.S. home, making it the largest energy expense for most homes. A wide variety of technologies are available for heating and cooling your home, and they achieve a wide range of efficiencies in converting their energy sources into useful heat or cool air for your home. In addition, many heating and cooling systems have certain supporting equipment in common, such as thermostats and ducts, which provide opportunities for saving energy.

When looking for ways to save energy in your home, be sure to think about not only improving your existing heating and cooling system, but also consider the energy efficiency of the supporting equipment and the possibility of either adding supplementary sources of heating or cooling or simply replacing your system altogether.

Decide Whether to Replace Your Existing System
If your furnace or boiler is older than 20 years, chances are it is a good investment to replace it with a high-efficiency model with the guidance of a good contractor. Also consider a replacement now if your system is one of the following:

• Old coal burner that was previously switched over to oil or gas
• Old gas furnace without electronic ignition. If it has a pilot light, it was probably installed prior to 1992 and has an efficiency of about 65% efficient (the least efficient systems today are 80%)
• Old gas furnace without vent dampers or an induced draft fan (which limit the flow of heated air up the chimney when the heating system is off).
• If your furnace or boiler is 10–20 years old, and you are experiencing discomfort or high utility bills, hire a highly-qualified home performance or heating contractor who can help you evaluate your existing system. Often it will be more cost-effective to improve house insulation and air-tightness, repair or insulate ductwork, or tune up your system.

Calculate Your Return on Investment
If you have an idea of how much it will cost to install a new system, use the chart below to calculate how much money you are likely to save each year with a more efficient system, and what your return on investment is likely to be. Remember, when fuel prices go up, your savings will go up.

1. Calculate Dollar Savings per $100 of Annual Fuel Cost
To determine savings from the table below, find the horizontal row corresponding to the old system's AFUE, then choose the number from that row that is in the vertical column corresponding to the new system's AFUE. That number is the projected dollar savings per hundred dollars of existing fuel bills.

For example, if your present AFUE is 65% and you plan to install a high-efficiency natural gas system with an AFUE of 90%, then the projected saving is $27 per $100. If, say, your annual fuel bill is $1,300, then the total yearly savings should be about $27 x 13 = $351.

2. Calculate Return on Investment
ROI = first year savings ÷ installed cost

Example: ROI = $351 ÷ $2,500 = 0.14 = 14%

Sizing a Heater
For each type of heater you need to consider the room size:
A rule of thumb calculation to choose a heater which is an appropriate size for your room:
1. multiply the width X height X length (in metres) to get the volume of the room in cubic metres (m3).

2. multiply the volume by 60 to get the heating requirement in watts (W). This is for Christchurch conditions.

Example: A room has a 3m stud, and is 4m wide and 5m long. The volume is 3x4x5=60m3. Heating requirement is: 60 X 60 = 3600W. Therefore a 3.6kW heater is needed (1000W=1kW).

If the room is uninsulated, draughty, or has a large area of external wall or large windows, it will require a larger heater (up to 20% more).

If it is well insulated with ceiling, wall, floor and window insulation, it should require a smaller heater (up to 25% less).

Water Heaters

Fuel Choice and Sizing

Fuel Options
The most efficient systems available are generally gas-fired. If you currently have an oil-fired boiler, your best options are to purchase in indirect tank that connects to your boiler (best if your boiler is relatively new), or an integrated unit that provides space heat and hot water in one. Electric water heaters are not recommended.
If you currently have an electric water heater and natural gas is available in your area, a switch might save you a lot of money. Even though electric models have a higher energy factor than fuel-burning models, electric resistance is a very expensive way to generate heat. It does not have great environmental benefits either, since electricity is only as clean and efficient as the fuel (often coal) that generates it. Before you rule out electricity, though, check with your utility company. It may offer special off-peak rates or options for purchasing renewable power that may make electricity a more attractive option for you.

Sizing a Water Heater
The capacity of a water heater is an important consideration. The water heater should provide enough hot water at the busiest time of the day. For a storage water heater, this capacity is indicated by its "first hour rating," which accounts for the effects of tank size and the speed by which cold water is heated. First hour rating is included in product literature and on the EnergyGuide label alongside efficiency rating. To determine your family’s first hour rating, use the Peak Water Demand Worksheet
For tankless, solar and indirect water heaters, sizing requires a few other calculations that your installation contractor can help you with.

Compare Life-Cycle Costs

Heat Pump Water Heaters
If you currently have a standard electric resistance water heater, models that use a heat pump are more efficient because the electricity is used for moving heat from one place to another rather than for generating the heat directly.  The heat source is outside air or air in the basement or room where the unit is located. Heat pump water heaters are not very common at this time. They are available with built-in water tanks called integral units, or as add-ons to existing hot water tanks. A heat pump water heater uses one-third to one-half as much electricity as a conventional electric resistance water heater. In warm climates they may do even better, but there are few sources for these products. Several manufacturers have discontinued their lines of heat pump water heaters due to lack of consumer and contractor awareness.

How to Get the Most from Your Water Heater

To get the most from your water heater:
Set water temperature to a maximum of 125 degrees. If you have an automatic dishwasher that does not preheat its own water, set the water heater thermostat to 140 degrees. (This ensures proper cleaning.)
Wrap water pipes outside heated spaces (e.g. crawl space, attic) to maximize your energy efficiency and keep your pipes from freezing.

Finally, install water-saving showerheads and faucet aerators to reduce overall water usage; in turn, potentially lengthening the life of your water heater.

Minimize Operating Costs
Even if you aren’t going to buy a new water heater, you can save a lot of energy and money with your existing system by following a few simple suggestions.

Conserve Water. Your biggest opportunity for savings is to use less hot water. In addition to saving energy (and money), cutting down on hot water use helps conserve dwindling water supplies, which in some parts of the country is a critical problem. A family of four each showering five minutes a day can use about 700 gallons per week—a three-year drinking water supply for one person! Water-conserving showerheads and faucet aerators can cut hot water use in half. That family of four can save 14,000 gallons of water a year and the energy required to heat it.

Insulate Your Existing Water Heater. If your electric water heater was installed before 2004, installing an insulating jacket is one of the most effective do-it-yourself energy-saving projects, especially if your water heater is in an unheated space. The insulating jacket will reduce standby heat loss – heat lost through the walls of the tank – by 25–40%, saving 4–9% on your water heating bills. Water heater insulation jackets are widely available for around $10. Always follow directions carefully when installing an insulation jacket.

Insulate Hot Water Pipes. Insulating your hot water pipes will reduce losses as the hot water is flowing to your faucet and, more importantly, it will reduce standby losses when the tap is turned off and then back on within an hour or so. A great deal of energy and water is wasted waiting for the hot water to reach the tap. Even when pipes are insulated, the water in the pipes will eventually cool, but it stays warmer much longer than it would if the pipes weren’t insulated.

Lower the Water Heater Temperature. Keep your water heater thermostat set at the lowest temperature that provides you with sufficient hot water. For most households, 120°F water is fine (about midway between the “low” and “medium” setting). Each 10°F reduction in water temperature will generally save 3–5% on your water heating costs. When you are going away on vacation, you can turn the thermostat down to the lowest possible setting, or turn the water heater off altogether for additional savings. With a gas water heater, make sure you know how to relight the pilot if you’re going to turn it off while away.

The Building Envelop

Find and Seal Air Leaks
Hidden air leaks cause some of the largest heat losses in older homes. Common air leakage sites include:

• Plumbing penetrations through insulated floors and ceilings
• Chimney penetrations through insulated ceilings and exterior walls
• Fireplace dampers
• Attic access hatches
• Recessed lights and fans in insulated ceilings
• Wiring penetrations through insulated floors, ceilings, and walls
• Missing plaster
• Electrical outlets and switches, especially on exterior walls
• Window, door, and baseboard moldings
• Dropped ceilings above bathtubs and cabinets

The best material for sealing these hidden air leaks depends on the size of the gaps and where they are located. Caulk is best for cracks and gaps less than about 1/4" wide.

Expanding foam sealant is an excellent material to use for sealing larger cracks and holes that are protected from sunlight and moisture. Today's products are safe for atmospheric ozone. Backer rod or crack filler is a flexible foam material, usually round in cross-section (1/4" to 1" in diameter), and sold in long coils. Use it for sealing large cracks and to provide a backing in very deep cracks that are to be sealed with caulk.

Use rigid foam insulation for sealing very large openings such as plumbing chases and attic hatch covers. Fiberglass insulation can also be used for sealing large holes, but it will work better if wrapped in plastic or stuffed in plastic bags, because air can leak through exposed fiberglass. Specialized materials such as metal flashing and high-temperature silicone sealants may be required for sealing around chimneys and flue pipes. Check with your building inspector or fire marshal if unsure about fire-safe details in these locations.

Upgrade Inefficient Doors and Windows
About one-third of the home's total heat loss usually occurs through windows and doors. If your existing windows have rotted or damaged wood, cracked glass, missing putty, poorly fitting sashes, or locks that don't work, you may be better off replacing them.

If your windows are generally in good shape, it will probably be more cost-effective to boost their efficiency with inexpensive products purchased from your local building supply or hardware store.

• The quickest and cheapest option is to seal all window edges and cracks with rope caulk.
• Another solution is to weatherstrip windows and doors with a special lining that is inserted between the window and the frame. For doors, weatherstrip around the whole perimeter to ensure a tight seal when closed. Install quality door sweeps on the bottom of the doors if they aren't already in place.
• If you plan to stay in the house for more than a few years, install storm windows. These come as plastic films you affix to the existing window, or a removable and operable piece of glass that inserts behind the existing window, or most commonly are installed on the exterior within the window opening which also provides protection to the existing window.
• Finally, prevent radiative heat gain and loss in the summer and winter by installing insulating curtains or drapes on the interior.

Insulate
Insulation is your primary defense against heat loss through the house envelope. However, putting insulation into a house after it is built can be pretty difficult. If there isn't any insulation, the best option is to bring in an insulation contractor to blow cellulose or fiberglass into the walls.

Attic. Adding insulation to an unheated attic is easier than insulating existing walls and is likely to have a greater impact on comfort and energy use. If there is no floor in the attic, simply add more insulation between the ceiling beams, either loose fill or unfaced fiberglass batts. In most of the country, a full foot of fiberglass or cellulose insulation is cost-effective in the attic floor. However, it is critical to install fiberglass batts properly in order for them to do the job. If you do it yourself, make sure you read up on correct installation practices.

Basement. Materials that could be damaged by moisture, such as fiberglass batts and cellulose, should never be used to insulate a basement. Interior vapor barriers can also be very damaging because they prevent basements from drying to the inside. Interior basement insulation should start with rigid foam installed against the basement walls. If you are considering finishing your basement and using it as a living space, seek the advice of an experienced professional.
If you have a crawl space, it should be sealed, not ventilated. To do this, use 6-mm thick polyethylene sheeting as a moisture barrier to cover the ground and seal tightly to walls and columns. Then use rigid foam to insulate the foundation walls. In the South, it is important to keep an uninsulated band for inspection of possible termite tunnels.

References:
Community Energy Action - www.cea.co.nz
American Council for an Energy Efficient Economy - www.aceee.org

Southwest Garden Neighborhood Association, 4950 Southwest Avenue, Saint Louis, MO 63110