Q. I have a question for you pertaining to the filter in my heat pump. I have had two different contractors telling me two different stories and Iím not sure which one to believe. My filter opening in my heat pump is 19 inches wide by 22 inches deep-- a strange size. One person said that it is very important to ensure all the air passes through the air filter on the furnace and I should purchase a custom filter that covers the exact 19 x 22 opening. The other person said that it is not a big deal to cover the entire opening and I should be able to purchase a 16 x 25 inch standard filter from the store. It will hang out 3 inches on the front and will be about 1.5 inches short on each side, but the majority of the air flow will go through the filter. If I go with the first approach, I must purchase a heaver filter that blocks more of the air flow. If I go with the second approach, I then can purchase a lighter filter that allows more air to flow through. What should I do?
A. As usual, the answer lies somewhere in the middle. The big secret is that basic air filtering in a forced air heating and cooling system is more for the equipment than for the buildingís occupants. If lots of household dust, pollen, pet dander and bas ic atmospheric air pollutants get into your system they will land upon the coils in the air handler and if they coat them like a sweater they will effectively create an insulating barrier. Over time itíll look like the layer of lint you pull out of the d ryer filter after a big load of clothes. Then, as the fan blows the air past the coils, little heat exchanging will take place and the system will be spinning its wheels with respect to both heating or cooling the house. Thatís why I always recommend an nual coil cleaning during normal servicing regardless of how good you think your filtering is.
If you use the smaller non-custom made filter, it will pull roughly 85 percent of the air through the filter. Having a custom made or a filter you cut up to fit tightly will obviously close that gap somewhat but if you properly maintain your system one could could argue itís not worth the effort. But certainly, the cleaner the air the better off both you and the system are.
You might consider sealing off this filter access and install return air grilles that accept standard size filters there. They open with little clips on one edge and swing open on a hinge to expose the filter. You can also peek through the grille and se e how dirty itís getting as time goes on. Most houses these days have one or maybe just two return air locations so installing them wouldnít be such a big deal. Or, you could go way high tech and have a state of the art electronic filter installed that would effectively do the job a whole lot better than any disposable or washable filter and will efficiently reduce any airborne particulates that float around your house. And as cold and flu season sets in on us I am seeing the sense of also adding a UVC sanitizer light into the air plenum that will kill 99.9 percent of the germs and viruses that will fly past and through garden variety home air system filters. Then youíve really got clean air.
Q. Hey Jim, I am going to Florida next week for five months and was wondering if leaving my thermostat set at 50 degrees is sufficient here in Maryland.?
A.50's pretty cold but nothing will likely freeze. Shut the water off and pour some antifreeze in the sinks, tubs, showers and toilets so that they don't either freeze or dry out. Turn the water heater off at the panel box. When you turn the water bac k on next spring check carefully for anything leaking.