Super-insulating a home has its benefits, and its costs

In energy-conscious home remodeling, ''payback'' is the catchword of the '80 s. With the newly discovered need for more and better insulation, double and triple glazing, tighter framing, passive solar gain, and all of the other energy-oriented home improvements, the old question of ''do we really need it?'' has become ''how many years or months does it take to pay back the investment?''

But there are two other questions that are much more relevant:

* Are we going to live here or sell the old place? If sale is imminent, no major remodeling is practical other than cosmetic improvements. If you will continue to live there, anything you want and can afford is worth the price.

* What are the further, hidden costs of any of these energy-saving projects? If you are going to stay, they can be considerable, and only now are remodelers beginning to find out about them.

Suppose, north of the Sunbelt, you go for the concept of super-insulation to R-42 or more, including ceilings and walls, with the complete caulking and sealing that should go with the job. For a 1,500-square-foot house, that will cost you around $1,700.

If you are going to sell your house, you'll have made a good investment in these energy-conscious times. You probably will get all of your money back in the sale.

But if you decide to remain in the house, you may discover that, along with the solutions offered by super-insulation, you may have acquired a few problems.

One of the results will be pools of water dripping from the insides of your windows, especially around cooking time, and particularly if you cook with gas. Another might be an odor of formaldehyde which may be an irritant to some people.

What has happened?

Your super-sealing job has stopped the normal ''breathing'' that your house used to do. It has stopped the interchange of outside and inside air which you used to get from drafts and seepage. Ultra-tight, your house traps all humidity (generated especially by cooking) as well as all the chemical effusions and odors that formerly were not noticeable.

To correct the new problems you will have to buy dehumidifiers and either empty them or add drainage piping, and you will also have to add a ventilating system to force air changes.

In an ultra-tight house your range-venting system won't exhaust to the outside unless you open a window to give it some air to exhaust, bringing in the cold that you wanted to keep out.

If you also added new aluminum double-glazed windows, plus storms and new entry doors, you spent from $6,000 to $10,000, depending on the quality you chose.

If you are selling, you might get as much as a 50 percent payback because home buyers are learning to appreciate good windows and doors.

But if the storm windows in the assembly also are aluminum, and all in an aluminum framing, you will have layers of ice on the inside of the panes in very cold weather.

There isn't much you can do about it other than add wood-framed storms outside.

There are also other hazards which you also might run into.

Rigid plastic foam panels are becoming popular for insulating walls, and for good reasons. They are easy to cut and install and are quite inexpensive. Too, they have a high R-value and have the added advantage of insulating where batts or blown-in insulation don't - over studs and other framing. Such framing amounts to more than 20 percent of the exterior of a house.

While these panels have been in use for about 10 years, they also create a new problem with wood siding. The foam provides no support for nails which are used to apply the siding. After a few weather changes both gaps and sagging can show up in the siding, mainly in horizontally applied wood-bevel siding.

The weather changes are important because the foam panels are such good insulators. They form their own vapor barrier and reflect heat so well that the wood siding reacts more to temperature and builds up too much moisture, causing excessive movement in the wood which loosens it. This doesn't happen much, but it can be a problem.

Meanwhile, you will find wood-siding guarantees more limited if the siding is to be applied over foam panels.

Overall, the best advice is to be more wary and studious if you are doing the job yourself. If you are planning to have the job done, find a qualified contractor. Find out if the contractor is aware of new technology. And ask for references. A reputable contractor will be able to give you a list of the people for whom he has done work.

One way to locate a reliable contractor it to look for a member of the National Association of the Remodeling Industry (NARI) or similar national group.

NARI has begun certifying its members in certain remodeling specialties. As the program develops it will give the homeowner more assurance of protection against hidden hazards.