Ever since oil has skyrocketed in price, energy experts have struggled to keep up to date with advice for cost-effective choices for heating.

If oil hangs in at the $5 per gallon level (fortunately, as of today, it is dropping), electric heat starts to look competitive.

Traditional electric heaters are considered 100 percent efficient. They were not always a wise choice, given the high cost of electricity in Maine. There are, however, some options that make it worthy of consideration.

The first one is temporary spot heating. If you have a small room where there is no central heat or the room is hard to heat, a small portable electric heater is a good option for short-term use – while you are in the room. Small plug-in electric heaters are not for permanent use. They should not be left unattended.

Second is an electric radiant floor. This is a plastic heating grid that is usually installed under a tile floor. This is a permanent heating technology that is very comfortable.

It can be used for heating an entire room, but is limited to the higher-cost electricity as its sole fuel.

A third choice is a heat pump. Heat pumps are interesting devices that extract heat from the air, ground or water. This heat is pumped out of the source material and compressed into usable heat while chilling the air, ground or water it extracts the heat from.

The heat pump runs on electricity. The “magic” of this process yields heat that is one-third to half the cost of straight electric heat. This is referred to as the “coefficient of performance,” or COP. A COP of 2 means that we get two times more heating value than the actual electricity used to run the heat pump.

Given the current cost of oil and electricity, heat from a heat pump is a real bargain. If a heat pump yields a COP of 2, it is equivalent to oil that costs about $2.90 a gallon. A COP of 3 is equivalent to oil at $1.95.

The limitation with heat pumps has been the cost of the hardware and electricity. The most efficient heat pumps have been units that extract heat from coils buried in the ground or ones that use well water as a heat source. These get pricey since you have to either dig up the yard or install a well or two.

The new technology on the heat pump scene has some roots here in Maine. Nyle Corp. licensed a technology from a former Carrier Corp. scientist several years ago and developed the “cold climate heat pump.” This is a device that uses air as the heat source. The limitation with air-source heat pumps in our climate is that when it is very cold out, it becomes difficult to extract enough energy from the air to heat a home efficiently.

This new technology uses two compressors in series to efficiently extract heat with a decent COP. The beauty of this system is that it is fairly compact and does not require coils in the ground or wells. These systems offer COPs of 2-3 with a seasonal average of 2.5.

Another company, Hallowell International, was started in Bangor a couple of years ago by a former Nyle employee to manufacture a similar product.

If you are thinking about heating and air conditioning, this is a very appropriate technology. It makes much more sense than the other heat pump systems that are currently available.

Questions for Tom Gocze should be sent to homefront@bangordailynews.net or mailed to The Home Page, Bangor Daily News, P.O. Box 1329, Bangor 04402-1329. A library of his practical home-improvement videos, reference material and a home-project blog are at bangordailynews.com/thehomepage.