Q. What is the purpose of paint primers? Are they necessary when there are now self-priming paints and are these as good as separate coats of primer and paint? Also, if I paint my bathroom white (it is now yellow) do I need a primer?
A. The main purpose of most primers is to improve adhesion of the finish paint by providing a non-glossy layer that grips both the surface to be painted and the finish paint.
However, there are many special-purpose primers; some of these seal in stains that would otherwise bleed through the finish paint, some control rust, some fill pores, some lock in odors, and so forth.
Some primers are water-based and easy to use, some are oil-based, and some have solvents such as shellac.
Self-priming paints have come a long way in the last decade, and a few of them – such as Valspar Ultra Premium Duramax and Behr Premium Plus Ultra – have achieved high ratings with some users.
But not all users are pleased with self-priming paints; some say it takes two or three coats of self-priming paint to achieve the same results that can be achieved with one coat each of primer and regular paint.
Self-priming paints are generally more expensive than regular paints, though in any contracted paint job labor always comprises about 90 percent of the cost. My own inclination is to stay with primer and regular paint for the time being.
If the yellow paint in your bathroom is in good condition, free of stains and is not glossy, you should not need a primer. You should use special bathroom paint, such as Zinsser’s Perma-White, which resists mildew and could give one-coat coverage.
Q. I live in a small condo with a loft attic and no basement. The tank-type water heater and gas furnace are located directly over my bedroom. I am thinking of installing a tankless water heater. What are the pros and cons? Are tankless heaters efficient and reliable?
A. You already have a gas supply, which is one of the requisites for a tankless water heater. The main advantage, of course, is the compact size that eliminates the big storage tank of a conventional water heater.
Other advantages, assuming the tankless heater is working properly, are an instant and steady supply of hot water and, in many cases, some saving in the cost of heating water. An income-tax rebate of up to $1,500 is available if an eligible heater is installed before the end of this year.
Because of the compact size, tankless heaters can be installed in much smaller spaces than a tank heater, even outdoors in some warm climate regions.
The main disadvantage is the installation cost, which is generally considerably more than a tank heater.
Many tankless heaters need replacement after about 20 years. I can’t vouch for performance and reliability; that is up to the manufacturer and installer.
An experienced installer, a solid warranty and top product (see www.energystar.gov and search for Tankless Water Heaters) are your best protections.