An electric radiant heating system is a great way to achieve draft-free winter comfort. No blowing air means you can get by with a lower thermostat setting than you would with a forced-air heating system. That, and the radiant system's zonability — which lets you set different rooms at different temperatures — makes it less expensive to operate than a gas furnace and even, in some cases, a little less than a heat pump.

However, assuming you also want central air conditioning in your new home, the cost of installing whole-house radiant heat and a ducted cooling system will be much greater than that of an all-electric heat pump.

In certain situations, installing radiant panels can be appropriate - especially as a supplement to a central heating system in:

In the summer, the heat pump works just like an air conditioner to provide high-efficiency cooling.  In winter, it works in conjunction with the existing gas furnace to provide high-efficiency, low-cost heating.  During the majority of the heating season, the heat pump is all you'll need to keep your home comfortable.  During the coldest days—typically when the temperature drops below about 25-30 degrees Fahrenheit—the gas furnace will serve as your supplemental heat source. (In an all-electric heat pump system, supplemental heat would be provided by electric resistance coils, like those used in an electric furnace.)

Will an add-on heat pump continue to be more economical than a gas furnace-air conditioner combination? That depends, of course, on what happens with energy costs. Although we don't know for sure if gas prices will again reach the levels they did during Winter 2005/2006 (when Springfield customers were paying over $1.20 for each therm of gas), indications are that future winter gas prices are likely to remain well above $0.75 per therm. (In Winter 2006/2007, for example, the average price of gas has hovered between about $0.95 and $1 per therm.) Given that assumption, add-on heat pumps will continue to provide a more economical option than a gas furnace and air conditioner combination.

If you're replacing your windows to improve your home's looks and comfort, by all means, choose high-efficiency multiple-pane models with low-E film or coating and an inert gas filling. Your energy savings should quickly off-set the cost difference between these and low- efficiency single-pane units.

But, if your goal is simply to increase efficiency, there are far more cost-effective things you can do — including installing storms over your existing windows, making sure the existing windows and frames are sufficiently caulked and weatherstripped, and insulating your walls. And remember, insulating your walls could qualify you for CWLP's Insulation Rebate.

CWLP's Home Efficiency Handbook contains more information about window efficiency. CWLP electric customers can order their free copy by contacting the Energy Services Office.

First and foremost, make sure you select a builder with a reputation for quality, energy- efficient construction. Insist on receiving detailed specifications outlining each efficiency feature to be included in the home. Among the features we strongly recommend are:

Before going further, there are two points you need to be aware of. First, your current system was probably 65% efficient when new. If it's in really bad shape, its efficiency is now probably no better than 50%. Second, although there is one furnace that can achieve up to 97%-efficiency under certain conditions, its maximum operating efficiency in most Springfield homes is 94%. So your real decision is whether to go from 50% to 80% or from 50% to 94%.

To calculate the energy-savings difference between two systems, divide the low efficiency by the high efficiency and subtract that figure from 1. In your case, the 80%-efficient furnace will reduce your current heating costs by 37% (1 - [.50/.80] = .37). The high-efficiency system will cut your costs by 47% (1 - [.50/.94] = .47).

Now, let's say your current heating costs average $750 a year. The 94%-efficient furnace would save you 10% ($75) more a year than the 80%-efficient model would. Dividing the $350 installation-price difference by the annual energy savings shows that you would achieve a payback on your efficiency investment in about 4.5 years. Since a well-maintained gas furnace can generally be expected to last 15-20 years, you should have many years of savings to spend or reinvest after you achieve payback. Of course, your actual savings and payback rate will depend on the actual purchase and installation price of the systems you consider.

The CWLP Energy Experts don't usually recommend a tankless system as a replacement for a centrally located traditional water heater. A gas unit, with its standing pilot light, probably will provide little or no savings over a well-insulated tank heater. An electric tankless system might be a little more efficient than a conventional water heater, but the savings most likely will be too small to offset the high purchase cost.

Tankless heaters are good for some specific point-of-use applications, such as when distance from a centralized tank heater makes it hard or inconvenient to get a sufficient supply of hot water to a kitchen or bathroom. In this case, you could install a tankless heater right in that room.

Otherwise, we recommend using a traditional tank heater and taking steps — like wrapping both the tank and water pipes with insulation and installing heat traps on the pipes where they exit the top of the tank B to ensure it will operate as efficiently as possible.

Thermostat setback refers to the practice of setting your thermostat at higher- or lower-than- normal temperature so your air conditioner or furnace will run less during periods when you need less cooling or heating. The most appropriate times to set back your thermostat are at night and during the day when you expect to be away from the house for several hours.

Thermostat setback is an excellent way to cut your energy bills. For every degree you set your thermostat up in summer and down in winter, you can reduce your heating- and cooling-related energy use by about 2% or 3%— assuming the setback period lasts for several hours (such as overnight) each day. Setback is particularly easy if you use a programmable, electronic setback thermostat.

Under the right circumstances, shutting off heating and cooling to unused rooms might save you some money. But the savings typically will be small. If not done correctly, this procedure could actually increase your energy costs and seasonal discomfort.

Your savings will probably be greatest if the rooms you want to close off are near the air handler/furnace. Because of their proximity to the source of the conditioned air, these rooms would normally be warmest in winter and coolest in summer. By closing off the air supply to them, you can redirect more conditioned air to other areas of your home. This will let you improve comfort in the spaces you use most often without the need to increase energy use.

If your duct joints aren't well sealed, pressurization caused by shutting supply vents at the end of a duct run (in the room) can cause conditioned air to leak through the joints. Wrapping the joints in aluminum foil duct tape will help reduce this problem.

If you have duct dampers, you should use them instead of shutting room vents. Located inside the ducts, these devices can be closed to keep air from entering the ducts they control. This eliminates the potential for the duct pressurization problems mentioned earlier. If you have duct dampers, you will see a small metal tab on the duct about a foot from the main trunk. If the tab is lined up with the duct, the damper is open. To close the damper, turn the tab 90 degrees.

To avoid choking off too much air flow through your system, the rooms you close off should not represent over 20% of your home's total square footage. If you have a heat pump, we do not recommend closing off air supply to any part of your home.

Siding alone will have almost no impact on the insulating capability (R-value) of your exterior walls. Even if the siding comes with a rigid board of insulation backing, this polystyrene beadboard is usually so thin and loose fitting that it will increase R-value only minimally.

If your walls have never been insulated, we strongly recommend you blow insulation directly into the wall cavities before installing your siding. This will bring your total wall R-value to about 13. The cost of doing this can vary from a few hundred to a few thousand dollars depending on who does the work.

To raise the R-value by an additional 5 points or so, you can sheath the walls with rigid board insulation before installing the siding.

Insulating an existing brick wall poses problems not encountered when insulating walls covered with wood and other siding materials. In those types of structures, you would drill right into wall surface (either going directly through or lifting it and drilling into the sheathing below). With brick, however, you don't want to drill into the exterior surface and there's no way to lift the brick to expose the sheathing below.

If the walls are brick veneer over wood framing and you will be doing major indoor remodeling, you could remove the plaster or sheetrock from the interior surfaces of all your exterior walls and fill the exposed stud cavities with blanket insulation. Or you could drill through the interior wall surface and blow in loose-fill cellulose.  (You would need to patch the wall surface when done.)  If neither of these options would work for you, your only other real choice would involve blowing insulation into the wall cavity through holes drilled into the stud wall's top and sole plates. To do this, you will work in the attic and basement or crawl space rather than outside, as you would normally do when blowing in wall insulation.

If your walls are solid brick, if access to wall plates is blocked by a shallow roof or slab foundation, or if the cost of installing the insulation is higher than you want to pay, you can take other steps to reduce energy costs and discomfort. These include moving beds and chairs away from exterior walls, sealing air infiltration points, and using shades or drapes to cut heat loss through windows.

You can improve your home's lighting efficiency by replacing incandescent bulbs with either halogens or compact fluorescent lamps (CFLs).

Screw-in halogen bulbs use up to 17% less energy than, last up to three times longer than, and are similar in size and shape to standard incandescent "A" bulbs. But they have light output equivalencies only up to 100 watts.

For your reading lamp and in many other applications, you will be better off replacing your incandescent bulbs with CFLs. They use 70% to 75% less energy and last 10 to 13 times longer than incandescents. They are available in wattage equivalencies ranging from 25 to 150 watts. You'll need a 39-watt CFL to replace the incandescent bulb now in your reading lamp.

Yes. You could use either a standard (one-way) or a three-way CFL. Each would provide a different effect.

The standard CFL works in a three-way lamp exactly the same way a one-way incandescent does - the light remains off for three of every four clicks of the lamp's switch and you get only one level of light. Just like a three-way incandescent, a three-way CFL would provide you with three different lights levels that would be equivalent to the light output of a 50/100/150-watt incandescent.

A thermostat setting of 110°F should be adequate to guard against excessive attic heat buildup while ensuring the fan doesn't run more than absolutely necessary.

Heat buildup in an attic (especially one that is under-insulated) can contribute greatly to a home's summer cooling load. Ventilation systems, like your temperature-controlled fan, reduce the amount of buildup, thus lowering cooling costs and improving comfort. However, because your power vent uses electricity, its energy will cut into your overall savings.

A more efficient way to ventilate your attic would be to install a well-designed passive system that uses no electricity at all. A good passive system could include soffit vents, installed every 8' to 12' along the roof eaves, and a continuous ridge vent. This "low-to-high" venting arrangement would allow a cooling draft of air to be pulled continuously through the attic.

Whatever venting method you use to control attic heat buildup, remember that the best way to limit heat transfer from the attic to your living space is to have adequate insulation in the attic.  We recommend a minimum attic insulation level of R-30.  R-38 is preferred.

For "simple" appliances - like light bulbs, irons, hair dryers, TVs and radios - you can multiply the device's wattage rating (amps x volts) by the number of hours you use it each month. Divide your answer by 1000. That tells you how many kilowatt-hours (kWh) of electricity the appliance uses per month. Finally, multiply the kWh by your electric cost (which, on an annual basis, averages about 9.5¢ per kWh for the majority of CWLP's residential customers). (Cost estimates last updated September 30, 2008)

This calculation method doesn't work well for more complex systems - especially air conditioners, refrigerators, water heaters and others that cycle on and off during operation. For help estimating the energy use of these types of appliances, you can contact the Energy Services Office.

More information about calculating appliance energy usage, including a chart listing the approximate energy use of many common household appliances, can be found on our Appliance Energy Use page.

We recommend replacing the entire system. Your condensing unit is nearing the end of its expected lifespan and could begin experiencing serious problems at any time, especially if the new A-coil you install is not properly matched to the old condenser. By replacing both units at once, you will reduce the likelihood of component mismatching that can lead to compressor failure.

Replacing the entire system will also lower your cooling costs. Fifteen years ago, even the highest efficiency air conditioners had SEERS of only about 10. Today, SEERs of 14 or more are common. (In fact, federal standards require heat pumps and central air conditioners manufactured after January 23, 2006, to have minimum SEERs of 13.) Going from a SEER 10 to a SEER 14 will reduce your cooling costs by 40%!

Another consideration might be to replace the old air conditioner with a heat pump (either all-electric or as an add-on to a gas furnace).  This would allow you to reduce both your cooling and heating costs, and could qualify you for CWLP's Heat Pump Rebate.

Sunlight shining in your home can cause a tremendous amount of internal summer heat gain. Applying a light-reflecting film to west and east-facing windows that receive a lot of sunlight can cut your cooling costs. Actual savings will depend on the VLT (visible light transmittance) rating of the film you use. The lower the VLT, the less light the film will allow to enter your house and the greater your savings will be.

You'll save year-round and improve winter comfort if you use a light-reflecting film with  low-E capabilities. This type of film reflects both light and infrared energy back toward its source, thus helping prevent furnace and body heat from radiating out through your windows in winter.

The first thing you should do is to try to purchase a lot that will allow you to orient your home so one of the two longest walls faces due south.  Then design the house so that the majority of your windows are on this wall, with large roof overhangs shielding them from as much summer sun as possible.  This will allow your home to benefit from a maximum amount of solar gain in winter, when you need it, while limiting solar gain in summer, when you don't need it.  Second, because windows are a very common source of cold air infiltration in winter, limiting the number and size of windows on both the west and north sides will also help enhance comfort and efficiency when the cold winter winds blow.

Don't forget, when designing your passive solar home, to make sure it is well insulated.  A well-insulated building will help block the sun's heat from entering the home in summer and will help keep solar gain inside the home in the winter.