Dear Jim: I want more months of use from my swimming pool and I enjoy really warm water. The cost to operate my gas pool heater is too high now. How effective are the roll-out solar pool heater kits that I have seen? – Ron G.

Dear Ron: Solar heating is ideal for swimming pools. In fact, more solar kits are used to heat pool water than for any other purpose. In colder climates, you will get an extra month or two of pool use. If the water gets uncomfortably warm in midsummer, run the solar unit at night to cool it.

The new solar pool heating kits are easy to install yourself. They can be laid on the house or garage roof, the ground, a support rack, etc. Since they are black and lay flat, they are barely perceptible when installed. The plumbing hooks into the current filter-pump system with just one valve.

It is most convenient to install a kit with an automatic controller. You set the pool water temperature that you desire. The controller directs the water to the solar unit only when the pool water needs additional heat.

The reason that do-it-yourself solar kits are so popular for pools and spas is their simplicity and low cost. It requires a much simpler collector design to efficiently heat pool water to only 85 F than to the 130 F required for domestic hot water.

Many kits use flexible sheeting with water passages throughout and they are sold in rolls. You just roll them out and attach the incoming and return pipes from the pool or spa. Some of the kits even have Velcro straps so they can be rolled up and stored away during the nonswimming seasons.

Although they appear to be just a black sheet of tubes, they are specially designed. For example, the web between the tubes on some have an engineered concave shape to redirect the sun’s rays to improve efficiency. Others have dimples formed into the tubes to create turbulence of better heat transfer.

There are several other unique designs of solar pool heating kits. One design mounts inside your attic and can help to cool your house and lower your air-conditioning bills. Using a small fan and a heat exchanger, it draws the heat out of the super-hot attic area to heat the pool water.

Another kit, good for cold climates, uses a 4- or 8-foot parabolic reflector dish that is mounted on a post. The parabola focuses the sun’s heat on the water in the center of the dish. It heats the water to higher temperatures.

If you are planning to install an above-ground pool, consider a pool kit with hollow solar decking around it. It looks just like a typical deck, but the pool water flows through it and is heated by the sun. Another advantage is that the deck stays comfortably cool when sunbathing.

Dear Jim: I have a problem with light bulbs burning out quickly. The package says that they should last about 700 hours but they don’t last anywhere close to that. What can be causing them to burn out? – Ann W.

Dear Ann: If it is only happening in one or two fixtures, then you may have bad switches. This in effect is continually switching them on and off. Look for even the slightest flickering and replace the switches. If most of your bulbs burn out prematurely, you are probably getting voltage surges in your house. The best cure for this is to install a whole-house surge suppressor on your circuit breaker box or under the electric meter.