How Does An Air Conditioner Work?
An air conditioner is basically a refrigerator without the insulated box. An air conditioner is doing exactly the same thing as your fridge, except it dumps the heat it takes out of the controlled area and dumps it outdoors instead of in your kitchen. To understand what goes on in the system, let's start where the "freon" gas enters the compressor located typically in the outside part of the unit.
As the refrigerant gas enters the compressor, it squeezes this freon gas that has just absorbed heat from the indoor air, causing it to become extremely hot. This is just like what happens near the end of a bicycle pump when you push the handle down. The air being compressed into the end of the pump will get hot, because all the heat that the air inside it contained, is squeezed into an area that is many times smaller than where it just was. This now high-pressure freon gas, that is now many times hotter than it was before it got squeezed, runs through a set of coils outside where a fan blows on it to cool the high temperature gas, so that a large portion of this concentrated heat is removed from it. The fan and coil arrangement outside are very similar to a radiator on a car.
As the outside unit (or radiator) cools this hot vapor, it condenses into a liquid just like steam condenses into water when it loses its heat. This high pressure freon liquid which has now had a lot of its original heat forced out of it, is then pulled back into the house where it waits its turn to pass through a tiny opening that is the entrance to the indoor coil that sits within your home's air stream.
By using this tiny opening to "back-up" the pressure on the outdoor part of the system, it allows the compressor to maintain a low pressure side within the indoor coil that is in your home's air stream. When the cooled High pressure gas finally passes into this low pressure area, the difference in pressure causes part of it to immediately expand into a gas. In a sense, this is like the compressor working in reverse, because now the cool freon is occupying a bigger area, so the heat that was left in it now has to spread itself out over its bigger size.
This need to use its limited heat over a now bigger gas molecule, causes it to rapidly become quite cold, so that as it passes through the indoor coil, the air passing over this coil (the radiator effect again) is cooled and then spread through your home by your home's duct work. Meanwhile the heat that was taken out of your home's air, has entered the warming freon gas so that when it gets back to the compressor the whole process is repeated. Back to Top
How Does a Furnace Work?
The furnace is the most important component of a central heating system. It houses all the working parts. So when you replace the furnace, you replace the vital operating parts of your heating system. It is by choosing from among the different models and brands of furnaces available that you determine the quality and cost of your business’s heating for years to come.
The furnace is part of a forced-air system. Warm air is forced, or blown, through a system of air ducts to each of the rooms in the office. Office air drawn into the furnace passes through a filter, where dust and other small particles are trapped. A blower unit blows the filtered air through the furnace, and the air absorbs heat.
Gas Heat. If it is a gas furnace, the heat is supplied by the burning of natural gas. A mixture of gas and air flows into the burner and is ignited by the pilot. Combustion occurs, and warm air from the burner flame rises to fill a chamber known as a heat exchanger.
The heat exchanger becomes hot. Office air passing around the heat exchanger absorbs that warmth, continues into the air ducts and the heat is distributed through the business.
The by-products of combustion pass upward through a venting system and escape through a vent in the roof.
Electric Heat. If the furnace is electric, heat is generated by an electric heating element. Electric current traveling through the element creates heat. By the heat transfer processes called conduction and convection, heat is transferred into the air stream and flows through the air ducts into the rooms of the business.
The Thermostat. Whether you heat your office with gas or electricity, a wall thermostat will be installed. This measures room temperature and turns the central heating system off or on as the temperature rises or falls to designated levels. Careful location of the thermostat is an essential consideration in maintaining maximum comfort levels in your business. Back to Top
We turned on the furnace for the first time, it smelled so bad we were worried it was carbon monoxide or something else was wrong. Is this normal?
The odor is normal because dust collects on the heat exchanger over the summer, and turning it on for the first time simply burns the dust off. Carbon monoxide is odorless, so you could not smell it. Homeowners should install a good carbon monoxide detector to make sure none of this deadly poison is present in their homes. When you turn on your furnace for the first time leave the windows open to dispel the odor quickly. This is also the ideal time to schedule a maintenance appointment to make sure your furnace will work properly when you need it. Back to Top
What I can do to assure proper operation and safety of our furnace?
Yes. The first thing to check before turning on your unit is to make sure nothing flammable has been stored next to the furnace over the summer. Use the following as a guide:
-Run your heater for a few minutes now, before you need it. If you wait until the first cold morning to discover is isn't working, you'll find yourself on a waiting list before a heating and air specialist can come to fix it.
-Change the filters regularly. Dirty filters restrict air flow, reducing efficiency and worse case, can cause the heat exchanger to overheat. Disposable fiberglass filters should be replaced. Electrostatic or electronic filters need to be washed regularly.
-Be sure all access panels are secure, with all the screws in place.
-Be sure the thermostat is set in the heating mode. Just setting the dial above room temperature will not activate the heat if it is still set in the air conditioning mode. Back to Top
How do I decide if I should repair or replace?
When an older unit breaks down, the decision to replace or repair the unit can be difficult. There are many factors to consider. Your technician should present you with options and explain the advantages and disadvantages of each. Here are some of the things to consider before you make a decision.
First of all, what is the cost of repair vs. replacement? In addition, what is the age and efficiency of the old unit vs. the efficiency of a new unit? Your dealer can help you calculate your approximate energy savings based on your current energy costs.
Warranty coverage should be a factor in your decision. You'll also want to consider how long you plan to stay in your present home. Careful consideration of all these factors can help you come to the best decision. Back to Top
How do I choose the right system for my house?
Looking at new heating and cooling equipment can be very confusing. There are so many options to choose from and so many variables to consider. Beware of contractors that may try to sell you more capacity than you need. Even though more capacity may sound like a good thing, a system that's too big for your home will heat or cool too quickly. This short cycling can lead to wear and tear, inadequate dehumidification and a reduced product life.
Choosing the right equipment depends on several key variables: First of all, the number of heating and cooling hours required. This will vary according to the area of the country where you live. The size and thermal efficiency of your home will also need to be taken into consideration. Your dealer will take into account the age of your house, how it faces the sun, your floor plan, the insulation of your home and other variables before making a recommendation. The cost of fuel in your area will also factor into your dealer's recommendation. Back to Top
What is an energy-efficient furnace?
Simply, if you have an 80% efficient furnace, it basically means for every dollar spent on fuel, 80 cents is used to heat the home and 20 cents is lost up the chimney. Furnaces are rated with efficiency levels. What does this mean?
Furnaces are rated with Annual Fuel Utilization Efficiency (AFUE). The minimum AFUE number is 80. The efficiency improves with a higher AFUE number. Back to Top
What is the difference between an 80% efficient furnace and a 90% efficient furnace?
Both furnaces will heat the home equally well, but the 90% furnace is more efficient, saving you approximately 10% in operating costs.
• 80% furnaces typically vent up a chimney because they have high exhaust temperatures that remove products of combustion.
• 90% furnaces have such a low exhaust temperature they have to be power-vented outside in PVC pipe.
Do I need to have my furnace or air conditioner serviced every year?
Having your equipment serviced on an annual basis can prolong the life of your equipment and save you money on operating costs. Back to Top
How can I learn more about Energy Star Products?
You can learn about energy efficient products for the home, and determine how efficient your home is today by going to www.energystar.gov. Back to Top
What's the most common mistake people make in trying to save energy around the house?
Common mistakes people make include:
-Letting the furnace or air conditioner salesperson sell them a unit that's much bigger than they need.
-Not getting the ducts checked for leakage when installing a new heating and cooling system,
-Thinking that "since heat rises, we only need to insulate the attic." Floors over a basement or crawlspace, walls and windows also matter.
-Not using ceiling and portable fans to improve comfort in the cooling season. They use very little electricity. Use them to circulate air in the house, to make the house feel cooler by doing this, the thermostat setting for your air conditioner can be raised to 85°F, and still maintain the same comfort as the lower setting.
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© 2007 Howell Heating, LLC.
2009 West Broadway Ave, Ste. 400-200 Forest Lake MN 55025 (651) 398-1100 email: zack@howellheating.com
We serve the north east metro, including: Forest Lake, Lino Lakes, Hugo, Shoreview, Circle Pines, Linwood, Columbus, Stacy, Wyoming, North Branch, Chisago Lakes, Lindstrom, Stillwater, Shafer, Scandia, Lake Elmo, Roseville, White Bear Lake and surrounding areas.
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