Countertop appliances can help save money in the kitchen

Q. I prefer to use the kitchen stove for cooking, but I’ve heard that using small countertop appliances is more energy efficient.

Is this true? Is there a simple way to determine which appliances are the best to use?

A. What makes one cooking appliance less expensive to operate than another is how much of the heat actually gets into the food compared to how much heat ends up in the room air in the kitchen and is lost. As much as 50 percent of the heat can be lost from a typical kitchen stove.

This is why it is important to match the size of the pot to the size of the burner/ element on a cooktop. If the pot is too small, a lot of the heat is lost around the sides of the pot. Also using the recommended type of cooking utensil material for the specific cooktop type is important.

During the winter, the selection of the cooking appliance is not as important as it is during the summer. Any heat that is lost to kitchen air just reduces the heating load on the furnace or heat pump. It is not a one-to-one trade-off, but it does reduce the central heating cost somewhat.

During the summer, any heat lost to the room air must be removed by your home’s air conditioner. This creates a double cost — for both cooking and home heating — so appliance selection is more important.

Another consideration is overall cooking time; you want to minimize the amount of water vapor emitted from your cooking, and control uncomfortable indoor humidity levels. During the summer, it makes sense to use small appliances outdoors.

It is not always a simple decision as to when it is best to use a smaller countertop appliance instead of the kitchen oven or cooktop. If the cooking time is the same as with the larger appliance, then the smaller, lower-wattage appliance will generally use less energy.

Another factor is the quality of the cooktop and oven. If your oven is selfcleaning, it likely has heavier wall insulation than a standard oven and will save energy. Minimize the use of the selfcleaning cycle because it uses a lot of energy to get the oven super-hot.

Whenever possible, select small countertop appliances that have a thermostatic control for the cooking temperature; these will provide more precise results than appliances that just

have a low-to-high temperature dial. A built-in timer is also good to avoid overcooking food and wasting more energy.

A small countertop convection oven uses much less wattage than a full-size oven. The oven’s convection fan uses very little electricity and the circulating air cooks foods much faster, which means less heat will be lost to the room.

Using a pressure cooker to prepare some items also reduces cooking time, and it’s a good way to tenderize tough cuts of meat.

Microwave ovens use less electricity than standard ovens or cooktops because they cook quickly, and nearly all the heat goes into the food items. However, if you can bake several dishes at once in your full-size oven, it will use less electricity than running the microwave several cooking times. Baking many potatoes is an example where the range oven is better to use.

To calculate the cost to operate an appliance, find the wattage rating on the item’s nameplate. Divide this by 1,000 and multiply the result by your $/kWh electric rate to get the operating cost per hour. If the nameplate lists amperage, multiply it by 120 to get watts. For appliances that have a thermostat, reduce the operating cost by about 50 percent.

Q. My asphalt-shingle roof has black stains on it, and it looks bad. I cleaned it, but the stains came back.

What is causing this? Is there anything I can put on the roof to stop the staining?

A. The black stains are algae and fungal growth on the shingles. It usually is worse in shaded areas.

Lay bare copper wire along the roof ridge. When it rains, copper ions will flow down over the shingles and to retard this growth.

There are also DIY roof cleaning and stain-blocking chemicals from Saver Systems. Once the roof is cleaned, the stain blocker should be reapplied every two-three years.

Send inquiries to James Dulley, Arkansas Democrat-Gazette, 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit www.dulley.com.