Sustainable Sources

By Doug Garrett
(this article first appeared in the Austin American Statesman in 1996, but it is still relevant today)

We all know that we can pay our auto mechanics a little now for routine service, or pay them a lot later for a major repair. The same idea holds true for your air conditioner or heat pump. If you don’t service your air conditioner or heat pump regularly, you’ll find yourself uncomfortable and broke.

In this article the term air conditioner will apply to a heat pump or a standard air conditioner. Both benefit equally from annual service tune-ups.

An air conditioner is a very tough piece of equipment. It is engineered to withstand all sorts of abuse and keep on running. This is great in most respects, but it can lead to complacency about maintenance. Like a car, air conditioners need regular tune-ups to run properly.

Without regular maintenance an air conditioner loses about 5% of it’s original efficiency for each year of operation. This means that the 12 SEER unit that you bought just a few years ago may be functioning like a 9 SEER unit today! The good news is that you can recover most of that lost efficiency through regular maintenance. Studies show that with regular tune-ups a unit will maintain up to 95% of it’s original efficiency. This means that the cost of an annual tune-up is recovered very quickly in savings on your monthly electric bill and reduced repair costs. A properly serviced air conditioner will also do a better job of dehumidifying your home.

Many local air conditioning firms offer special prices at this time of the year (spring and fall, when weather’s not as extreme –Ed.). Some even offer annual service programs that insure that you will be reminded of the need to service the unit at the beginning of the cooling and heating seasons.

The service check should include cleaning the condensing unit coils, checking the amp draw of the compressor, oiling the fan motors, checking that belts are well adjusted, and checking the system operating pressures and temperatures against the manufacturers specifications. One of the most important items to check is the coolant level (previously known as Freon) in the air conditioner. A system that is only 10% low on coolant will cost about 20% more to operate! The Air Conditioning Contractors of America (ACCA) recommends that coolant levels be checked every year.

If your unit is low on coolant, and more must be added, there are new laws governing its use. Freon is a chlorofluorocarbon (CFC) that will damage the Earths protective ozone layer if released into the atmosphere. The laws governing CFC’s now do not allow your air conditioner contractor to add Freon to a leaky system. [Ed note: CFCs are no longer allowed and various alternative refrigerants are now common.] They are first required to find and fix the leak in the system. Don’t ask them to violate this law as they may lose their license if they are caught doing this.

There are some things in addition to yearly tune-ups that you can do to help ensure a high level of comfort and proper system operation. First, buy good filters and change them regularly. Next, keep bushes and other materials away from the outside unit of your air conditioner. Another good idea is to avoid closing supply air outlets in your house. In almost all cases, closing supply outlets is harmful to the operation of the overall system.

All equipment, even the most reliable, needs routine maintenance. Complicated equipment like today’s air conditioners benefit in many ways from annual service. They recover much of their lost efficiency, they are less likely to suffer a major break down, they have a longer life span, they increase your comfort, and they operate for less money.

Tips to keep your attic cool

By Marc Richmond*

Picture this: It’s a hot and humid summer day. You head for the indoors and some relief from your trusty air conditioning (A/C) system. Three hours later, you’re slightly cooler, but you’re wondering why your A/C unit hasn’t shut off yet. Here’s why: all day long, solar radiation has been heating up your home through the windows, walls, doors and especially the roof. Your attic temperature can easily reach over 140 degrees. That heat up there is working its way through your meager attic insulation into your home and through the A/C ductwork, located in your attic, into your cooling system. Your A/C system has to fight that added heat to change all that hot air in your home into cool air. You can install solar screens for the windows, porches around the house for shade, and plant trees around the home, but what do you do about the roof which accounts for a third of all the heat build-up of your house?

Here are a few options:

Ventilate your attic with ridge and soffit vents. Vents are louvers, grills, or screen materials which allow passage or air through them. They are typically installed along the top peak (ridge) of your roof, at the top of the side wall (gable), and on the underside of your roof overhang (soffit). Ventilation moves air through your attic by force of wind or by heat rising through natural convection. This leaves cooler air sitting on top of the insulation on the attic floor. Ventilation also has the ability to remove humidity which has built up in your attic and which reduces the effectiveness of your insulation. It is often best to hire a contractor to install these.

Insulate your attic to R-30. R-30 is roughly a 10 inch thick layer of insulation material above your ceiling. This is a job for any handy homeowner or it could be handed over to a contractor. When installing the insulation, be careful not to block your vents.

Install a radiant barrier between your roof and your attic insulation. A radiant barrier is an aluminum foil material which prevents 95 percent of the heat that radiates from your roof from reaching the insulation on your attic floor. It comes in a roll and is stapled to the underside of your roof rafters, or as a metallic paint. Radiant barriers are sold in most building material supply centers and can be easily installed by a homeowner. This system can save you up to eight percent on your summer cooling bills.

When it comes time to replace the roof, use roofing material which resists or reflects heat – typically lighter colors are best, though there are some new materials which are effective at reflecting infrared radiation (heat) with a more ‘traditional’ color.

This article first appeared in the Austin American Statesman and was republished by us in 1997. *We have since edited the article.  At the time of publication, Mr Richmond was with the City of Austin’s Green Building Program; he now is president of Practica Consulting.