Frequently Asked Questions

Grassi Refrigeration is in Walla Walla, WA is proud to serve customers from across the Valley with a range of HVAC services. Since our beginning in 1958, we have been committed to providing our customers with the highest level of residential and commercial services. We provide a range of services to home and business owners throughout the area including heating and cooling repair, equipment installation, routine maintenance plans, and more.

Our goal is to build long-lasting, quality relationships with our customers. We are proud to be the team our customers confidently refer their friends and family to. We are an authorized dealer of Carrier products. As part of our commitment to our customers, we have taken some time to answer some frequently asked questions about filters and energy efficiency ratings. We hope you find the information below helpful.

For additional questions, to schedule service, or for more information about our residential and commercial HVAC services, please contact us today at 509-529-9700. We look forward to hearing from you!


What is a MERV rating?

The MERV rating of a filter refers to the Minimum Efficiency Reporting Value. This standard rates how effective the filter is. The higher the MERV rating, the finer the filtration is, which means more airborne contaminants and dust particles are filtered out of the air.

What size filter do I need?

To determine the size of the air filter you need, simply remove the old filter and look at the sides of the filter. A label should be affixed that indicates the approximate size of the filter. If you are unable to find the size of your filter, you can call us with your model number and our filter expert would be happy to help you. When you replace your filter, it is a good idea to write the date of replacement on the side of the filter so that you can easily assess the time for a change.

How often should I change my filter?

This depends greatly on the type of filter that you use. Most one-inch pleated filters should be changed approximately every 90 days. Larger pleated filters can last as much as 9 months to a year. It also depends on many environmental factors such as the number of occupants, pets, carpeting, and general activity.

Why is it important to change my filter regularly?

Better air filtration is the first step in improving indoor air quality. In addition, regularly changing the filters allows your air conditioner and furnace to stay cleaner and operate more efficiently. Our pleated, MERV-rated filters are made using Kimberly-Clark cotton-poly blended media and are tested according to ASHRAE standards. Our air conditioning filters and furnace filters are made with heavy-duty beverage board frames to prevent airflow bypass.

Heating and Cooling Efficiency Ratings Explained

If you are shopping around for ways to enhance your home or office’s energy efficiency, you will encounter several industry-standard efficiency ratings. Understanding these terms can help you find the products to suit your needs, and also determine if your current equipment is up to industry standards. The higher the efficiency of your HVAC products, the lower your long-term energy costs will be. As always, the experts at Grassi Refrigeration will help you choose the heating, ventilation, and cooling products that are right for you.


The SEER (Seasonal Energy Efficiency Ratio) of a product measures the cooling efficiency of air conditioners and heat pumps. The higher the SEER rating, the greater the efficiency, which results in greater energy savings. Today, U.S. regulatory agencies require all new products to have a 13.0 SEER rating or better.


AFUE (Annual Fuel Utilization Efficiency) measures the efficiency of gas and oil-fired furnaces. This number is measured in percentages and tells you how much of your fuel is used to heat your home or business, and how much fuel is wasted. The higher the AFUE rating, the greater the efficiency. Replacing an older furnace can help you save on your heating bills. The cost of replacing the furnace is paid back through lower utility bills.


HSPF (Heating Seasonal Performance Factor) measures the efficiency of a heat pump’s heating mode. The higher this number, the greater your cost savings and product efficiency. Today’s models are required to have a 6.8 HSPF.

For more information about increasing your home or office’s energy efficiency, please contact Grassi Refrigeration today at 509-529-9700. We are happy to answer any questions you may have about HVAC systems, including repair, installation, and maintenance. We are proud to serve customers in communities across the Walla Walla Valley.

Business Hours:
Monday - Friday: 7:30 am - 4:00 pm

Phone: 509-529-9700
Fax: 509-525-3666

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Heating & Cooling Contractor in Walla Walla WA | Grassi Refrigeration