Air conditioning economical installation


Up to a 40% reduction in output is expected when you mismatch systems. This is part of the study from the Refrigeration Service Engineers Society and was published in 2017.

Mismatched 13 SEER Outdoor/Empire Logo
10 SEER Indoor
Using factory refrigerant charge
of 8lb, 7oz
Cooling Performance:
Capacity (Btuh) 22,208
SEER 8.46
Superheat (°F) 54.54
Sub cooling (°F) 0.98
Liquid Pressure (psig) 209.94
Return Gas Pressure (psig) 58.42
Capacity Loss 40%
SEER Loss 38%

This is only a single example of what happens when you mismatch systems. A 38% loss in SEER. That means a very significant increase in your monthly utility overpayment. This study tells us that the indoor coil, the furnace or air handler and the outdoor unit need to matched just the way they were when the manufacturer submitted them for efficiency and btu testing. Any type of mismatch will cost you thousands of dollars in utility overpayments over the years.


Why would anybody mismatch a system?


This is primarily done to save the homeowner money on the initial installation by reusing older components. Would you buy a new car and have the dealership install the transmission from your older car to save a little money? The True Cost of a Home Comfort System is determined by the initial installed investment, but by adding all the expenses, including; initial investment, monthly utility payment, maintenance and cost of breakdowns. Installing an engineered matched compete package will always save you money while giving you comfort and peace of mind.

Ducting is the other major loss in a new installation. It gets hot in the attic and many service technicians choose to ignore the ducting because of that. It turns out that the majority of ducting in homes here in Southern California is undersized. There is a very good reason for it. The Uniform Mechanical Code only sizes ducting for heating-not cooling.

The UMC states that the size of the ducting need to be 2 squares of free air movement for every 1000 btus of heating. That means that 75,000 btu heater needs a round duct that is equal to or greater than 150 squares of cross sectional surface area. Using pi area of a circle we find that a 14 inch duct is 3.14 x 7 x 7 153 square inches. More than big enough. Well a 75kbtu furnace can have up to a 4 Ton drive blower (48,000btu of cooling) and cooling btus require 6 square inches of free air per every 1,000 btus of cooling. 48 x 6 288 square inches of cross sectional surface area. Using pi again we find that the minimum duct size to operate that 4 Ton unit is 18” ducting. Ducting only comes in even numbered sizes above 10 inch in diameter.

If your ducting is choking down your air system, you are paying for air conditioning that you are not receiving. A Ton of air is between 350 and 450 cubic feet of air per minute. The ideal in this area of the country is close to 400 cubic feet per Ton. Areas with higher humidity use a smaller amount of airflow and areas of desert use closer to the 450 cubic per air figure.

Virtually every study ever perform on heating and cooling btu loss in ducting has concluded that about 35% of all wasted btus in a heating and cooling system come from undersized, broken, restricted or improperly installed ducting. Have your ducting checked out every year and save a bundle on utility bills as well as increasing your comfort ratio.

How can I cash in on the government rebates?


We are here to help you and we’ll start you down the right path to maximizing your tax incentives and rebates. In the meantime you can do some of your own research for your projects by visiting some of these links. Here are some helpful web sites that enable you to maximize your rebate potential:

Federal Energy Star RatedWith a properly tuned up and operating system you can sit back and relax. Your heating and cooling system is doing all the work for you.

  • California Solar Initiative
  • Southern California Gas Company Rebates
  • Southern California Edison Rebates
  • San Diego Gas and Electric Rebates
  • Anaheim Utilities Rebates
  • Metropolitan Water District Rebates
  • Database for Renewable Energy
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